Dissertations / Theses on the topic 'Grain quality'

Doctor of Philosophy
Department of Agronomy
Jianming Yu
Knowledge of the genetic bases of grain quality traits will complement plant breeding efforts to improve the end use value of sorghum (Sorghum bicolor (L.) Moench). The objective of the first experiment was to assess marker-trait associations for 10 grain quality traits through candidate gene association mapping on a diverse panel of 300 sorghum accessions. The 10 grain quality traits were measured using the single kernel characterization system (SKCS) and near-infrared reflectance spectroscopy (NIRS). The analysis of the accessions through 1,290 genome-wide single nucleotide polymorphisms (SNPs) separated the panel into five subpopulations that corresponded to three major sorghum races (durra, kafir, and caudatum), one intermediate race (guinea-caudatum), and one working group (zerazera/caudatum). Association analysis between 333 SNPs in candidate genes/loci and grain quality traits resulted in eight significant marker-trait associations. A SNP in starch synthase IIa (SSIIa) gene was associated with kernel hardness (KH) with a likelihood ratio–based R[superscript]2 (R[subscript]L[subscript]R[superscript]2) value of 0.08. SNPs in starch synthase (SSIIb) gene (R[subscript]L[subscript]R[superscript]2 = 0.10) and loci pSB1120 (R[subscript]L[subscript]R[superscript]2 = 0.09) was associated with starch content. Sorghum is a crop well adapted to the semi arid regions of the world and my harbor genes for drought tolerance. The objective of second experiment was to identify quantitative trait loci (QTLs) for yield potential and drought tolerance. From a cross between Tx436 (food grain type) and 00MN7645 (drought tolerant) 248 recombinant inbred lines (RILs) was developed. Multi-location trials were conducted in 8 environments to evaluate agronomic performance of the RILs under favorable and drought stress conditions. The 248 RILs and their parents were genotyped by genotyping-by-sequencing (GBS). A subset of 800 SNPs was used for linkage map construction and QTL detection. Composite interval mapping identified a major QTLs for grain yield in chromosome 8 and QTL for flowering time in chromosome 9 under favorable conditions. Three major QTLs were detected for grain yield in chromosomes 1, 6, and 8 and two flowering time QTLs on chromosome 1 under drought conditions. Six QTLs were identified for stay green: two on chromosome 4; one each on chromosome 5, 6, 7, and 10 under drought conditions.

The use of oats for human consumption is increasing every day due to the health benefits of oat products. With the objective to study relationships among factors affecting oat grain quality, two Recombinant Inbred Lines (RIL) mapping populations (`ND030299' x `ND991151' and `ND030299' x `Souris') have been used in this study. The two populations with their parents and three check cultivars were evaluated in a square lattice design in 2008 and 2009 at two North Dakota locations. Data were recorded on the following agronomic traits: grain yield, test weight, 1000 kernel weight, thin kernels, heading date, and plant height. Chemical and grain physical analysis were performed for ?-glucan, oil, and groat percentage. A total of 4975 SNP markers were assessed on the two populations using a 32-bead chip platform developed by Illumina. QTLs for agronomic and grain physical traits were mapped and characterized in the two populations using Windows QTL Cartographer. Grain yield was positively correlated with test weight, thin kernels, plant height, ?-glucan content, and associated negatively with 1000 kernel weight. Thirty linkage groups using 1168 polymorphic markers were formed for population 05021, whereas population 05026 comprised 33 linkage groups using 1024 polymorphic markers. The 30 linkage groups of population 05021 contained from 3 to 62 markers, and varied in size from 15.8 to 225.3 cM for a total map size of 2601.7 cM. The 33 linkage groups of population 05026 comprised from 2 to 42 markers, and varied in size from 2.3 to 143.2 cM for a total map size of 1174.2 cM. Nineteen genomic regions on 14 linkage groups were significantly associated with agronomic and grain chemical traits in the population 05021. Fourteen genomic regions on 12 linkage groups were identified for agronomic traits in the population 05026. The same genomic region on LG 05021-16 was associated with thin kernels, test weight, 1000 kernel weight, and oil content. LG 05026-19 loci, from position 23.7 to 47 cM, had strong effects on heading date, plant height, and grain yield. The QTLs consistently detected across environments and between the two populations could serve as starting points for marker-assisted selection.

The work presented here explores the effect of storage on chemical and other characteristics of dry, free of added chemicals and pest-free barley and canola grain. This was achieved by measuring the changes in a number of variables of grain stored at different temperatures under laboratory conditions and in commercial storage. The following measurements were carried out: Viability, moisture contents (mc), oil contents (oc), whole grain colour, spectrophotometry of grain extracts, hydroxy methyl furaldehyde (HMF), changes in storage atmospheres, organic sulphide levels, tocol concentrations (vitamin E), Iodine Value (IV), Thiocyanogen Value (TV), Peroxide Value (PV), p-Anisidine Value (p-AV) and Acid Value (AV). The mc of canola and barley were within the range considered safe for storage. Oil content of canola did not change significantly with storage. Viability of canola stored at 4 and 25 °C did not change noticeably, but higher storage temperatures resulted in seed death. Barley maintained high viabilities at low temperatures, but was more susceptible to high temperatures than canola. Colour changes of whole barley grain in storage were pronounced and temperature dependent. Colorimetry of whole barley grain showed potential as a tool for monitoring quality changes in storage. Absorption spectra of grain extracts reflected chemical and physiological changes in storage. HMF, an indicator of Maillard browning, accumulated in short to medium term storage at 45°C and in long term storage at 25 and 35°C. Measurement of HMF was considered useful for monitoring quality changes of stored cereal grain. In a study of storage atmospheres, changes in the concentrations of carbon dioxide, carbon monoxide, oxygen, carbon disulphide and carbonyl sulphide were shown to be useful indicators of quality loss of grain in storage. Gas concentrations usually depended on storage temperature and time and reflected the storage history of the commodity. They indicated loss of carbohydrates and lipids by respiration, oxidative damage and deterioration of sulphur containing amino acids and other compounds. Oil quality indicators were consistent with oxidative damage to canola lipids in storage. IV, TV, and p-AV of canola oil did not correlate with quality of commercial samples. However, a relationship between increases in PV and high storage temperatures in canola was shown and AV increased in storage dependent on storage temperature and time. In barley and canola, the concentration of anti-oxidant tocol species (vitamin E) decreased at 35 and 45°C storage dependent on storage time. The overall tocol content as well as vitamin E activity decreased with storage decreasing the nutritional value of the commodities and indicating oxidative damage to lipids. It was concluded that the storage of dry, pest-free whole barley and canola grain at moderate temperatures (25-45°C) resulted in chemical and other changes. The consequence of these changes was a measurable reduction in the freshness of grain relevant to the nutritional, food technological and commercial quality of grain.

Master of Science
Department of Agronomy
P.V. Vara Prasad
Sorghum (Sorghum bicolor L. Moench) is cultivated as an important food grain in the semi-arid regions of Africa. Processed grain sorghum is traditionally consumed as porridge, couscous, traditional tô or beer. The quality of such foods is highly dependent upon grain characteristics. Sorghum grain quality traits mainly include kernel hardness, kernel weight, kernel size, protein content and kernel color. Grain quality traits are often influenced by environment, genotypes, fertilizer management and their interaction. The objective of this study was to determine the impact of different levels of nitrogen application (0, 45, and 90 kg ha[superscript]-1) on grain quality of selected sorghum genotypes. The field experiment was conducted at three locations in 2010 (Manhattan, Ottawa, and Hays) and at two locations in 2011 (Manhattan and Ottawa). The experiment was laid in split plot randomized complete bloc design and replicated four times. The main plots were assigned to three N regimes: control (0 kg N ha[superscript]-1), half recommended rate (45 kg N ha[superscript]-1) and recommended rate (90 kg N ha[superscript]-1). The subplots were assigned to twelve genotypes (six hybrids and six inbred lines). Plot size was 6.1 m x 3.0 m with a row spacing of 0.75 m. After harvest, grain quality traits (hardness, weight, diameter and protein content) were evaluated using standard procedures and the data subjected to statistical design using SAS. There were significant effects of genotype for most grain quality traits across both locations in Manhattan. Inbred lines SC35 and SC599 had maximum hardness at all locations while hybrid 95207, had the lowest hardness for all locations. Also, Inbred lines SC35 and Tx340 had maximum protein content at all the locations. While hybrids 95207, 26056, 23012 had the lowest protein content. Genotypes Tx430, SC35, had higher hardness and with higher protein content were classified as high quality. We conclude that application of N (45 or 90 kg ha[superscript]-1) significantly improved grain protein, but not other quality traits. There are opportunities to improve grain protein through fertilizer management and plant breeding.

Triticale (X Triticosecale Wittmack) is a high-yielding and vigourous interspecific hybrid between wheat and cereal rye. The crop is known for tolerance of abiotic stresses and high biomass production, and thus it has the potential to increase the profitability and productivity of growers in marginal environments and to help address the food production challenges of the 21st century. The original cultivars from the 1960s and 1970s usually produced grain with flour properties in between triticale’s progenitor species, and thus produced dough inferior to wheat and unsuitable for a range of food products, including loaf bread, flat bread, cakes, biscuits and crackers. However over the last 40 years, grain yield and grain quality for animal feed have been significantly improved through breeding and selection, and hence indirect improvements (or at the least, genetic drift in quality alleles) in its potential to produce good food products could be expected. Furthermore, significant advances in wheat quality research have produced vast amounts of information, methodology and technology that can be easily used to improve triticale quality, and the tastes of the modern consumer are different to those of 40 years ago. This thesis aimed to characterise the flour properties of a range of modern triticale cultivars and compare them to wheat, then investigate genetic, agronomic and post-harvest strategies to improve the value of the grain for a human food market. Focus was given to the two major scientific issues which have historically hindered the use of triticale flour in food products – poor gluten strength and high α-amylase activity – and to other quality traits of commercial significance. The grain and flour quality was quantified in up to 17 modern triticale cultivars grown in four environments over 2 years – Greendale, NSW in 2009 (JP09), Cowra, NSW in 2010 (COW10), both of which are typical triticale growing environments with poor soil and minimal fertiliser, Narrabri, NSW in 2010 (NARR10), which is a high yielding, high quality environment known for producing Australian Prime Hard wheat, and Stirling, SA in 2011 (SA11) which is a high protein, low yielding environment. Field plots were arranged in a randomised complete block design at JP09, COW10 and NARR10 with minimal irrigation; rust was controlled with fungicide. The three varieties from SA11 were sourced from commercial seed production lots. Grain was milled to wholemeal flour on a Newport Scientific hammer mill with 0.5mm screen, and to white flour on both a Quadrumat® Junior Mill and a Bühler experimental mill. Glutenin and secalin subunits were characterised by SDS-PAGE and the gluten properties were investigated using the SDS-sedimentation test and mixographs. α-Amylase activity was investigated spectrophotometrically and using the falling number test. These vi measurements were compared to estimations of grain protein, non-starch polysaccharides (NSP), starch content and fibre content using near-infrared transmittance (NIT). Flour protein was estimated by NIR (near-infrared reflectance). The pasting properties of milled flours were evaluated on a Newport Scientific Rapid Visco Analyzer according to AACC 76-21, except 10 mM AgNO3 was used in place of DI water to inhibit α-amylase activity. Grain hardness was measured by the Single-Kernel Characterisation System and moisture and ash content by standard oven methods. Colour of Junior milled flour was assessed using a Minolta Chroma meter CR-400. Finally, plain cookies were baked according to a standard recipe used to assess soft wheats. Variability in the glutenin and secalin subunits was small relative to global diversity amongst triticale cultivars, and reflects the narrow genetic base of material in Australian breeding programs. The gluten quality of these triticale cultivars was inferior to bread wheat but similar to soft wheat; however the protein content of triticale flour was significantly lower than wheat flour. Lower triticale protein content represents a change from early cultivars and reduces its capacity to form viscoelastic gluten. Cultivars Hawkeye and Vicuna were recommended for breeding to improve gluten strength in locally adapted germplasm. Much greater variability in starch and NSP characteristics were found in triticale compared to wheat, and the ranges overlapped between species. The cultivars Tobruk, Yukuri and Berkshire expressed equivalent α-amylase activity to wheat; cultivars Jaywick and Yukuri were found to have partially waxy starch. Triticale generally exhibited higher NSP, equivalent pasting properties, higher α-amylase activity and lower falling number than wheat checks. However, low falling number was not indicative of high α-amylase activity; this contradicts the assumptions on which previous triticale research was based and has implications for the interpretation of research and the use of falling number to compare triticale to wheat. Furthermore, an unexpected negative correlation was observed with NSP, where higher NSP reduced the slurry viscosity measured in the falling number test. Modification of the falling number test is recommended before it can be used in triticale breeding programs. Nevertheless, the observed genetic variability in starch characteristics and α-amylase activity indicates some triticale cultivars have waxy properties conducive to the production of noodles, and that certain lines exhibited similar late-maturity α-amylase activity to modern wheat cultivars: an indirect benefit of breeding and selection over the past few decades. Like starch properties, great variation was found amongst triticale cultivars for hardness, colour and milling yield. Berkshire displayed a grain hardness equivalent to durum wheat, suggesting a null allele at the rye softness protein locus (Sin locus); the remaining cultivars exhibited a grain hardness between soft wheat and bread wheat. The high milling yield and low fibre content of Tobruk (milling yield was even higher than bread wheat) suggested this line has a thin seed coat and thus would be an excellent parent for the genetic improvement of triticale milling yield. Average flour ash content was significantly higher vii than wheat in both statistical and practical terms, and a different bench mark needs to be used for low ash triticale flour compared to low ash wheat. Apart from Vicuna and Yukuri, triticale cultivars produced darker flour than wheat, however with modern consumer preferences tending towards ‘healthy-looking’ foods, darker flour should not be a hindrance to its utility. The overall results confirmed previous suggestions that triticale is suited to soft wheat products such as cookies, and hence their cookie quality was investigated. Although the dough behaviour and water absorption of triticale was different to soft wheat (specifically, triticale dough tended to loose large amounts of water during sheeting), triticale cookies were found to be equivalent to soft wheat cookies. Overall, the survey of quality amongst modern triticale cultivars suggested two things: firstly, sufficient genetic variation exists amongst current lines to breed triticale cultivars with significantly improved flour quality (comparable to wheat for some quality traits); secondly, there is a clear need to classify current cultivars into suitability for various end uses. This would facilitate efficient marketing to the milling industry and subsequent use in food products. Improvement of the the poor gluten strength in triticale was attempted by backcrossing locally-adapted spring breeding lines to DH265, a winter line which contained a modified 1R chromosome carrying two translocations from 1D of bread wheat – the Glu-D1d allele from 1DL (which simultaneously removed Glu-R1) and the Gli-D1/Glu-D3 locus from the distal end of 1DS. Single plant and plot selection was performed on five cross populations grown in multiple environments and the yield, protein content and gluten strength was analysed on F4-derived F7 grain. Lines containing the translocation had a slightly lower yield compared to the null lines and the triticale checks; but similar to the wheat checks for all except one cross (which was significantly less). This may reflect a loss of root system vigour, head length or higher selection pressure due to lower transmission rate of the translocation to offspring. The translocation slightly increased protein content in two populations and increased SDS-sedimentation height in one population (after accounting for the influence of higher protein content). However, no difference was detected between the overall average SDS-sedimentation height of the null lines and the wheat and triticale checks. This is partially due to large variability in SDS-sedimentation height within each cross population resulting from significant variability at other glutenin and secalin loci. Nevertheless, several lines were identified with grain yield equivalent to current triticale cultivars (and significantly higher than wheat) plus equivalent SDS-sedimentation height to wheat. Thus the translocation is a potential solution to the generally poor gluten strength of modern triticale cultivars. The viability of using existing variability for secaloglutenin alleles in the progenitor species was investigated as a means of creating new germplasm (‘primary triticales’) with high gluten strength. The HMW glutenins of five durum lines, and the HMW secalins and 75k γ- secalins of two rye lines, were defined using SDS-PAGE. These lines were then crossed, new primaries were produced, and grain was tested for the expression of secaloglutenin viii alleles, protein content and SDS-sedimentation height as an estimation of secalogluten strength. The secaloglutenin alleles were simply inherited from the parental plants and all were expressed normally in the offspring, however it was possible that mixed oligomers were formed between glutenins and secalins at the macromolecular level. Significant differences were observed in the SDS-sedimentation height of primaries originating from different durum parents, suggesting that selection of durum parents with high SDSsedimentation is a viable method for producing triticale flour with superior gluten properties. In south-eastern Australia, dual-purpose cropping is commonly used by growers to manage risk in mixed enterprise operations. A preliminary report of lower ash content but comparable protein content in triticale produced in dual-purpose systems was reported in Bangladesh and hence an experiment was conducted to assess the effect of biomass removal on grain yield, test weight, protein content and ash content of grain from four Australian dual-purpose triticale lines grown in five year-site environments (ash content is correlated with nutritional value, milling yield and flour colour). Ash content was either unaffected or increased by removal of biomass and both protein content and grain yield were reduced. It was concluded that although ash content was lower in some lines cut late in the season, the general effect was detrimental to quality and even when ash content was reduced, the effect was not large enough to reduce the level to that of wheat. Hence similar to wheat, dual-purpose triticale systems are not recommended for production of grain for a milling market. Poor milling yield in triticale is a key concern for millers. However, the high variability of grain hardness in triticale, historic problems with grain shrivelling, and lack of varietal classification has meant milling is usually conducted without adjusting settings to batch characteristics. Hence the importance of tempering moisture was investigated in three triticale varieties of varying hardness grown in two environments alongside a wheat standard. Milling yield and ash content both increased as tempering moisture was decreased from 15% to 11%. Triticale flour could be produced at a similar extraction rate as bread wheat provided there was no detrimental effect of high flour ash content. Surface area of larger triticale grain may also influence ideal tempering moisture, however further investigation is required. Tempering triticale to a moisture content appropriate to its physical grain hardness was essential in the optimisation of the milling process. The results of this thesis suggests that it is possible to produce triticale cultivars with flour properties equivalent to wheat, either through traditional plant breeding, chromosomal modification or creation of new primary triticales. However, with a changing market, many of the flour requirements have changed since triticale was first investigated in food products e.g. increased popularity of darker/wholemeal flours. Furthermore, general improvement of the crop over the last few decades has indirectly improved the grain e.g. breeding for plump grain has increased starch content and milling yield. Many of the current concerns of millers such as insufficient protein content, sticky dough, high α- ix amylase production, and low milling yield, can be overcome through fertilizer management, classification of varieties into grain hardness, milling yield and protein quality classes, and sourcing batches of grain with low α-amylase activity (avoiding measurement using the falling number test). There is a clear need to develop a marketing pathway for triticale flour in which cultivars and agronomic conditions that optimise milling quality are clearly communicated to growers. This is a prerequisite for the establishment of a price premium for batches of grain that meet the requirements of millers, processers and consumers. The higher yield and abiotic stress tolerance of triticale suggests that with focused breeding and an industry-wide push for efficient flour marketing, this crop could address some of the food production challenges of the 21st century.

Sorghum [Sorghum bicolor (L) Moench] is the second major cereal crop in Southern Africa after maize. Despite its importance as a cereal crop it is underutilised in Southern Africa because of insufficient characterisation and development of end-use quality evaluation methods for available cultivars, and the unattractive colour of some products from sorghum. This research aimed at developing simple methodologies for determination of important parameters of sorghum end-use quality, namely kernel hardness and kernel colour. The current research also set out to determine the cause for darkening of porridges made from white tan-plant sorghums and how this may relate to polyphenol oxidase activity. Sixteen Zambian sorghum cultivars grown during the 2008 and 2009 seasons of predominantly medium size, and ranging in colour from white to brown and red, with or without a pigmented testa were used. Endosperm texture of the sorghums determined by visual endosperm examination ranged from soft to hard. Abrasive hardness index values ranged from 6.28 to 19.64 and percentage water absorption ranged from 8.43 to 26.56%. Percent water absorption was significantly and positively correlated (r= 0.85, p <0.001) with endosperm texture and negatively correlated with abrasive hardness index (r=-0.89, p<0.01). The percent water absorption method could separate soft grains from hard grains just as well as endosperm texture and abrasive hardness index. The simplicity of the percent water absorption method makes it potentially usable by farmers and traders in remote areas where it can contribute to meaningful end-use quality assessment. The relatively dark colour of food products from white tan-plant (food-grade) sorghums can compromise their acceptability. The relationship between white tan-plant sorghum polyphenol oxidase activity (PPO) and porridge colour was investigated. Sorghums (including 28 white tan-plant samples grown in Zambia over two seasons), wheat and white maize were studied. Sorghum grain was intermediate in PPO between wheat and maize. When white tan plant sorghum and maize flours were cooked into porridges, they became darker with lower L* values. More importantly, the transition from white tan-plant sorghum flour to porridge caused a much larger reduction in mean L* value (27.9) than that with white maize (16.9). There were significantly negative correlations between all white tan-plant sorghum PPO activity and porridge L* values (r = -0.657, p < 0.01) and between Zambian white tan-plant sorghum PPO activity and porridge L* values (r = -0.710, p < 0.001). It is apparent that PPO activity in white tan-plant sorghums is an important determinant of the relatively dark colour of food products made from them, as is the case in wheat. Grain colour is an important quality indicator in sorghum-based foods and rural sorghum farmers in sub-Saharan Africa need simple, more accessible methods for its determination. The development of a simple quantitative method for sorghum grain colour assessment by analysis of the grains and their sodium hydroxide (NaOH) extracts was studied. Sixteen Zambian sorghums (white, red and brown types which were either tannin or non-tannin) from the 2008 and 2009 seasons and a Sudanese white tannin sorghum type were assessed for surface colour using Tristimulus colorimetry before and after treatment with NaOH. The NaOH extracts were also analysed using UV-visible spectrophotometry and reverse phase HPLC. Tristimulus colorimetry of the grain surface was able to distinguish white from coloured sorghums (brown and red) but was unable to separate tannin from non-tannin sorghum. UV-visible spectrophotometry and reverse phase HPLC of NaOH extracts from a representative set of the grains consisting of five sorghum types (red tannin, brown tannin, white tannin, red non-tannin and white non-tannin) separated the tannin from non-tannin sorghums regardless of grain surface colour. However, UV-visible absorption of NaOH extracts from the sorghum grains could not be related to grain surface colour as determined using Tristimulus colorimetry. Eleven phenolic compounds consisting of two flavan-3-ols, five anthocyanins and four 3-deoxyanthocyanins were identified in the NaOH extracts using UPLC/PDA/MS. NaOH extract from Framida *SDS[3845]23-2-1 (red tannin) contained all of the eleven compounds identified. The flavan-3-ols (catechin and +-catechin-3-O-gallate) were present in NaOH extracts of all the five sorghums. While some anthocyanins could be identified in NaOH extracts from all five sorghums, only Framida *SDS[3845]23-2-1 (red tannin), Sima (white non-tannin) and MMSH625 (red non-tannin) contained any 3-deoxyanthocyanins. Total peak area due to anthocyanins and 3-deoxyanthocyanins was higher for NaOH extracts from tannin sorghums compared to non-tannin. This was in agreement with the UV-visible spectrophotometry of the NaOH extracts which also separated the tannin from non-tannin sorghums. This shows that with NaOH treatment, it is possible to separate tannin from non-tannin sorghums. Colorimetry of NaOH extracts from sorghum may therefore be considered as a potentially simple and cheap alternative method for distinguishing tannin from non-tannin sorghums. The findings of this research provide a platform for the development of a system which promotes an integrated and inclusive approach in using the methodologies developed for sorghum end-use quality evaluation. The methodologies will form an integral part of the system which can be applied along the sorghum value chain in sub-Saharan Africa and involve various stakeholders such as the gene bank, sorghum breeders, cereal scientists and researchers, sorghum food processors, traders, rural farmers and consumers. The efficient application of this system could lead to increased sorghum production and utilisation and contribute significantly to food and nutrition security.
Thesis (PhD)--University of Pretoria, 2014.
tm2015
Food Science
PhD
Unrestricted

Field corn, Zea mays L., has been introduced to the market with pyramided Bacillus thuringiensis (Bt) corn technologies. These technologies reduce kernel damage from ear feeding caterpillar pests, including corn earworm, Helicoverpa zea (Boddie). The first generation Bt traits in field corn demonstrated limited activity on corn earworm feeding on grain in ears. The pyramided corn technologies have greater cumulative protein concentrations and improved expression throughout the plant, so these corn traits should provide an effective management tool against these pests. In addition, reduced kernel injury may also have a direct effect on physical grain quality. The results for this trial showed no relationship between number of damaged kernels and yield was observed for corn hybrid expressing the Herculex^®, YieldGard^®, or Genuity VT Triple Pro^® technologies. A significant relationship between both damaged kernels and test weight and damaged kernels and aflatoxin concentrations was observed in two technologies.

Wheat grain proteins and starch quality are commonly affected by abiotic stress conditions. In order to reduce the effects of climate change, there is need to select heat tolerant varieties usually grown in warmer regions. The University of Sydney’s Plant Breeding Institute is working to improve heat tolerance through novel crosses between commercial Australian wheat cultivars and the ancestral tetraploid, Emmer wheat (Triticum dicoccum), which has good heat tolerance. Several potential lines have been identified in the breeding programme, but there is need to determine their grain quality attributes. The objective of this project was to study the effect of heat stress on the quality attributes of heat stressed wheat grains grown in Narrabri, NSW in 2014. The heat stressed wheat plants were sown 2 weeks after the normal planting date. Thirteen out of 200 wheat lines were chosen, based on yield, 95% of Suntop and screenings < 30%. Protein content and swelling index of glutenin was determined. SDS-PAGE was used to analyse both the soluble and insoluble protein fractions. Proteomic analysis was used to determine the identity of the proteins of interest. Total starch content, amylose content of the starch and pasting properties of both flour and starch was measured. Heat stress caused an increase in protein content and swelling index of glutenin. Qualitative differences were observed for the soluble protein fraction when SDS-PAGE gels were run. The main proteins affected by heat stress, as identified by proteomics, were serpins. Serpins are termed soluble proteins, but their occurrence in the insoluble protein fraction maybe due to the effect of heat stress which changes solubility or the ability to associate with the gluten network. Therefore, serpins may be associated with improved heat tolerance. Since serpins require strong detergents for their extraction, they may be closely linked to gluten-forming proteins and thus may have an effect on dough quality.

Durum wheat is a strategic crop in Syria produced in high quantities and used mainly for the production of Arabic bread, bulgur and pasta. This investigation is the first known systematic study relating the grain quality of nine domestic cultivars to milling performance and pasta quality in order to map the Syrian dururn wheat characteristics onto the world market requirementsa nd henced eterminet he potential export developmentF. urthermore,i t examinest he influenceo f environment,g enotypea nd their interactiono n the physiochemicacl haracteristicso f five dururnw heat cultivars grown in five different locations under rainfed and irrigated conditions in Syria. AACC standardm ethodsw ere principally usedi n this investigation. Despitet he soundnesso f grainsr evealedb y elevatedt est weight (83.1-85.9k ghl*'), 1000k ernel weight (42.50-55.0g ) and falling number (433-597s ec), it is necessary to improve the kernel quality of Syrian durum wheat for the degree of vitreousness and total protein content (average quality data were 65% and 12.6% respectively) for better end-use product quality. In addition, irrigation demonstrated a significant effect on kernel quality traits, for example, irrigated samples showed the highest test weights. The importance of three physiochermical markers, namely total protein content, the degree of vitreousness and kernel hardness was substantiated and presented useful indicators for future development in Syrian durum wheat breeding programmes. Optimum cooking time of pasta and cooked pasta firmness correlated significantly with final viscosity (r = 0.51,0.73), dough development time (r = 0.69 and 0.63) and R., " (r = -0.64, -0.43) which indicated that RVA, farinograph and extensograph techniques were useful indicators of the cooking properties of pasta. Overall, this study revealed that to achieve the aim of improving the domestic production and expanding the potential export of durum wheat crop in Syria, both genetic and agronomic improvements are still required.

Variability of quality parameters between Australian wheat varieties grown in different locations and seasons causes difficulties in delivering uniform grains with consistent quality to local and international markets and in predicting functional performance in food processing and human nutrition. The objective of this thesis is to assess the relative contributions of genotype (cultivar), environment and their interactions to variability of quality traits such as test weight, grain protein content, β-glucan, fructans, total starch content, total arabinoxylans (T-AX), water extractable arabinoxylans (WE-AX), water un-extractable arabinoxylans (WU-AX), free, conjugated, bound and total phenolic acids. Three commercial Australian wheat (Triticum aestivum L.) varieties (Gregory, Janz and Peake) grown in 13 different geographic regions of Australia were used to examine wheat whole meal quality parameters. The grain samples were obtained from the National Variety Trials (NVT) conducted by the Australian Grains Research and Development Corporation (GRDC). Total starch, fructans, β-glucan and total T-AX were determined using Megazyme assay kits (Spectrophotometric analysis), arabinoxylan fractions were analysed using a spectrophotometric technique based on the orcinol-HCl method. Phenolic acid fractions were extracted using liquid nitrogen and analysed using a spectrophotometric technique based on Folin-Ciocalteau reagent and by high pressure liquid chromatography (HPLC) with measurements being made for individual phenolic acids in each fraction. Grain protein content and test weight were provided by NVT. The functionality of hard, soft and waxy wheat starch varieties, with and without the additions of WE-AX, was studied by a series of tests including thermal properties using Differential Scanning Calorimetry (DSC) and pasting properties using the Rapid Visco Analyser (RVA). All parameters measured and meteorological factors before and after flowering (temperature, rainfall and daily solar exposure) were analysed by statistical methods to deduce which factors influenced grain quality characteristics. The soil characteristics and fertilizers used were not available for all the locations, and because of the large number of missing values which could potentially bias the results of the correlation and regression analysis, these factors were not included in the analysis. Variability of the quality traits and starch functionality was described in terms of the influence of genotype, environmental factors and their interactions. This study showed that genotype contributed significantly to variability of all the traits tested. Genotype strongly influenced T-AX and WU-AX. Arabinoxylans levels were shown to vary among wheat genotypes. The average ratio of arabinose to xylose was 0.6 for each of the three varieties and this might indicate similarities of the substitution pattern of the xylose backbone by arabinose residues of the three cultivars. Growth environment was the main contributor to the variability of total starch, grain protein, WE-AX, β-glucan and test weight. Growing conditions had strong significant correlations (α = 0.01 and α = 0.001) with wheat grain protein, total starch, WE-AX, fructans and test weight. Growth conditions had moderately significant correlations (α = 0.05) with T-AX and WU-AX, while variability in WE-AX had an inverse and stronger correlations (α = 0.01 or α = 0.001) with the growing conditions compared to total AX and WU-AX. Arabinoxylan fractions (WE-AX and WU-AX) differed in solubility and in their variability due to environmental factors. These differences might be related to their different molecular weights, the incomplete cross-linking of WE-AX with other components, and to the loose binding of WE-AX to the cell wall surface. Genotype influenced all of the pasting properties of Gregory, Janz and Peake starches. The effects of growth conditions on starch pasting properties were significant on peak, breakdown and setback viscosities and pasting temperatures. Environmental temperature (minimum temperature days at < 0 ̊C) had negative correlations with pasting viscosities whereas total rainfall and average rainfall after flowering had positive correlations with setback viscosity. With regards to the addition of WE-AX to several wheat starches (Kukri, QAL2000 and QA-WX-83), the RVA pasting viscosities (peak, trough, final and setback) were decreased, whereas the DSC onset and peak temperatures were increased, but the change in enthalpy was decreased. The pasting and the thermal profiles of Kukri, QAL2000, and QA-WX-83 with WE-AX, have shown that WE-AX compete with starch granules for water. This study showed that phenolic acids are very variable compounds. The contents of free, conjugated, bound and total phenolic acids of whole meal flour from the same cultivar (Gregory, Janz and Peake) were different between locations and seasons. Cultivar was the main factor influencing free and bound phenolics of Gregory, Janz and Peake samples, which were grown in the 2010 season. Interactions between the genotype and the environment contributed strongly to conjugated and total phenolics. However, when two seasons were involved (2010 and 2012), genotype and all environmental factors had significant contributions to variability of soluble, conjugated, bound and total phenolic acids of Gregory and Janz samples (Peake was not planted in the 2012 season). Gregory cultivar had the highest amount of total phenolics in 2010 and 2012 seasons and its pattern did not change over the two seasons (the mean free phenolic concentrations tended to be consistently higher than bound and conjugated phenolics). Weather conditions in the 2010 season (average temperature before flowering, rainfall and solar exposure before and after flowering) influenced strongly conjugated and total phenolics. Weather conditions influenced all of the phenolic acids in the two seasons involved, 2010 and 2012. Benzoic acid derivatives (C6-C1) and cinnamic acid derivatives (C6-C3) followed different trends. The conjugated, bound, and free forms of 4-hydroxybenzoic acid, vanillic acid, syringic acid and sinapic acid all followed a similar trend with respect to growth location. The concentrations were highest in the conjugated form, less in the bound form, and least in the free form at all seven locations. On the other hand, the conjugated, bound, and free forms of p-coumaric acid, caffeic acid and ferulic acid followed a consistently different trend to the other four phenolic acids with respect to location. The concentrations were highest in the bound form, less in the conjugated form, and least in the free form at all seven locations. In conclusion, this study showed that genotype, environment and their interactions influenced grain quality parameters. Both genotype and environmental factors influenced pasting properties of starch. Genotype was the main influencing factor to the variability of T-AX and WU-AX. WE-AX competed with Kukri, QAL2000 and QA-WX-83 starches for water and influenced RVA and DSC parameters. Genotype and all environmental factors contributed significantly to the variability of phenolic acids in wholemeal flour.

A study was conducted to evaluate the quality characteristics in a comparative manner of grass-fed and grain-fed beef. Thirty two commercially bred beef steers were used. These steers were assigned to one of four treatments; grain-fed, grass/grain-fed, grass-fed and irrigated. These treatments were each reflective of the ration that would be provided to the animal. Individual animal weights were recorded every 28 days throughout the portion of the study. The grain-fed animals realized the highest (P<0.05) average daily gain with the grass-fed and irrigated having the lowest. The steers were harvested when they reached the pre-determined criteria, which was 0.4 inch back fat as measured at the 12th rib via ultrasonography, for the grain-fed or 800 pounds for the grass-fed animals. All animals, once harvested, were graded based upon USDA quality grades with results mirroring those previously mentioned. Carcasses were involved in an aging study in which all left sides of the carcasses were fabricated into primal cuts, vacuumed packaged and aged for 14 days while the right sides were dry aged during the same period. Shear force data were collected to provide for a measure of tenderness. All samples were significantly (P<0.05) more tender following aging with no difference being realized between aging techniques. Percent cutout was also calculated for the two techniques to quantify what difference, if any, existed. No significant difference (P>0.05) was shown between wet and dry aging with regard to percent cutout. Sensory evaluation was also conducted based upon the attributes of juiciness, tenderness and flavor intensity. For all three attributes grain-fed beef was favored (P<0.05). The panelists detected no difference in aging technique for any of the treatments (P>0.05).Carcass soft tissue chemical composition (lipid, protein and moisture) was also evaluated for the treatments. Grain-fed beef was shown to be highest (P<0.05) for overall percent lipid and lowest for percent moisture and protein. The grass-fed carcasses were the opposite, being highest for overall moisture and protein and lowest for lipid (P<0.05).

Wood is a major construction material that is used in many contexts, and for different purposes. Serious problems may arise, however, when moisture related deformations as twist occur in wood used in different types of building structures, joinery and furniture. Twist can be explained to a great degree by the helical deviation of the grain angle in relation to the longitudinal direction of the log or the sawn board. Wood fibres form a spiral within the tree, and this is a natural occurrence that is named spiral grain. The wood fibres close to the pith in Norway spruce form a left-handed spiral. In most trees the grain angle turns over to be right-handed with time. Sawn timber that exhibits large grain angles lead to problems of shape stability and stiffness in finished constructions. In this thesis the spiral grain in Norway spruce (Picea abies (L.) Karst.) was stated as well as the effect on sawn timber. The material was based on sample trees from Sweden and Finland. Samples were taken in twenty-two stands at different heights in tree. From six stands studs were sawn and dried for measuring twist and other deformations. The spiral grain was measured with the method scribe test on 390 log discs taken at the top-end of the logs. Account was given concerning changes in grain angle from pith to bark, regarding both increasing annual ring numbers and distance from pith. The development of grain angle over tree age was utilized to study whether annual growth, size of tree, height in tree as well as silvicultural treatments affected spiral grain. Moreover, the relation between grain angle and distance to pith (in mm) was used to forecast twist in sawn timber. The left-handed grain angle was at its greatest between the fourth and eighth annual rings. Thereafter for most trees the grain angle turned from left-handed to right-handed in a linear fashion, in a manner that was unique for each individual tree. The pattern of spiral grain differed significantly between different stands, regarding change of inclination with increasing age or distance from pith. The culmination of the grain angle close to the pith occurred at somewhat higher age higher up in the trunk. The grain angle decreased faster in top logs than it did in the butt logs. The largest trees within a stand had a grain angle that turned to right in a slower way than smaller ones. The thinning strength and type of thinning regime also affected the character of spiral grain in the remaining trees in a stand. There was an indication that strong thinnings, where fast growing trees are retained, may lead to more individuals in a stand that exhibit high grain angles under bark. With knowledge of the size and direction of the grain angle under bark, and the diameter of the log, calculations can be made that show how twisted the sawn timber will be after drying. This can be used for deciding whether an individual log can profitably be sawn and processed further or not. The grain angle under bark can be used to remove trees showing the greatest degree of spiral grain already in the first thinning. Silvicultural methods aiming at even and dense Norway spruce stands, which normally is practised in Scandinavia, will probably result in timber with relatively low risk concerning large grain angle and subsequent risk for twist in sawn wood.

The official U.S. standards for corn have been available for almost one hundred years. Corn grading system has been gradually updated over the years. In this thesis, we investigated a fast corn grading system, which includes the mechanical part and the computer recognition part. The mechanical system can deliver the corn kernels onto the display plate. For the computer recognition algorithms, we extracted common features from each corn kernel, and classified them to measure the grain quality.

Master of Science
Department of Grain Science and Industry
Carlos Campabadal Teran
The use of grain aeration as a tool to minimize post-harvest losses requires lower ambient temperature (≤ 20°C) and relative humidity (≤ 70%) conditions than what is usually available during the summer season in temperate climates and throughout the year in some tropical climate regions. Warm and moist conditions contribute to pest problems and increase dependence on chemical control for pest reduction as part of grain management strategies. The grain chilling technology is a non-chemical alternative to cool grain stored under high risk climatic conditions. For this research project, the grain chilling technology was tested in a 1,350-ton low moisture content wheat silo during the 2015 and 2016 summer harvests in Kansas. The grain temperature was lowered from a maximum of 39°C to a minimum of 17°C in less than 250 hours. The results showed that chilled grain maintained at temperatures under 20°C reduced the development rate of insect pests compared to grain stored at temperatures over 25°C and cooled with ambient aeration. However, the cost of grain chilling was calculated to be between 0.26 and 0.32 $/t higher than using ambient aeration. Through computer simulation it was possible to evaluate the performance of the grain chiller against four different ambient aeration strategies for paddy rice stored under the tropical climatic conditions of the North Pacific coast of Costa Rica. After six months of storage, the minimum grain temperature achieved through ambient aeration was 30.8°C using an aeration strategy based on a grain-ambient temperature differential greater than 10°C. Grain chilling lowered the average grain temperature from 35°C to below 15°C in 117 hours and the maximum average temperature it registered after six months of storage was 15.5°C. The economic evaluation of the simulated ambient aeration and chilling strategy determined that the operational costs of grain chilling were between 2 and 4 $/t lower than ambient aeration plus fumigation. However, the initial cost of the grain chiller made the net present cost (NPC) of the chilling strategy between 0.22 and 0.85 $/t higher than the cost of ambient aeration plus fumigation over a 10-year analysis. Several potential financial options were analyzed to make the grain chiller more economically feasible for a rice miller in Costa Rica. It was concluded that the grain chilling technology can reduce grain temperatures below 20°C in a relatively short period of time, which helps control insect populations and maintain grain quality during summer storage in temperate climates and in tropical climates. Utilizing grain chilling reduced operational costs between 78% and 88% when compared to using chemical control of pests. Additionally, it was determined that an initial cost of $74,700 for the grain chiller would require a 16% discount or at least 10,641 t to be chilled annually to make this technology viable for the Costa Rican rice milling industry. Leasing the grain chiller (ten equal payments of $10,926) or adding a premium sell price of 1 $/t to chilled rice would make this technology feasible compared to the traditional grain management strategies utilized in Costa Rica.

Processed grains that retain all three component parts - bran, germ and endosperm are known as whole grains. Epidemiological evidence suggests an inverse association between whole grain (WG) consumption and the risk of non-communicable diseases, such as cardio-vascular disease, type 2 diabetes, obesity and some cancers. The USA and Denmark have quantityspecific WG dietary recommendations, but other countries, including the UK, do not. Despite recognition that WG is an important component of a healthy diet, monitoring of WG intake in the UK is poor. Thus, there is a need to assess WG intake and its consequences in the UK population. The purpose of this work was to calculate WG intake and investigate potential associations with cardio-metabolic measures, nutrient intakes and intakes of other foods in the most recent UK National Diet and Nutrition Survey (NDNS) data and in the Newcastle Thousand Families Study (NTFS), a birth cohort from Newcastle upon Tyne. The estimated WG content of whole-grain foods identified in 3073 four-day food diaries was used to calculate WG intake of adults and children from the NDNS 2008-2011. A cereal food frequency questionnaire was developed with estimated portion sizes to estimate WG intake. WG intake was also calculated in the NTFS at 50- and 60-year follow-up. WG intake, which came mainly from breads and breakfast cereals, was low with an average of 20g/d in adults and 13 g/d in children of the NDNS and 19, 21 and 33g/d in the NTFS at ages 50, 60 and 67 years, respectively. In both studies WG was inversely associated with some, but not all, cardio-metabolic measures, after adjustment for confounding factors. Associations were small, but significant, suggesting that WG may have an important role in disease prevention. For example, a significant decrease in NDNS white blood cell counts were seen across tertiles of increasing WG intake, after adjustment for age, sex and total energy intake. In the NTFS members at 50-year follow-up, each 10g/d increase in WG intake was associated with a 0.1mmol/L reduction in total and LDL cholesterol concentrations, after adjustment for confounders such as sex, SES, medication use and smoking status. WG consumers also had overall better dietary profiles, with higher intakes of fibre, iron and magnesium and lower intakes of fats. iv The recent UK recommendation to increase dietary fibre intake will require a greater emphasis on consuming more WG. Specific recommendations on WG intake in the UK are warranted as is the development of a public health policy to promote the consumption of these important foods.

The effect of drought and simulated rainfall on wheat (Triticum aestivum L.) seed and grain quality during development and maturation, including delayed harvest, were investigated with pot-grown plants harvested serially in a ventilated poly tunnel. Grain quality was assessed by seed mean dry weight (MOW), moisture content, HFN (Hagberg falling number), 50S (sodium dodecyl sulphate sedimentation), nitrogen content, sulphur content a nd seed size; seed quality by ability to germinate and subsequent air-dry seed storage survival. Developmental duration was the dominant factor influencing quality: HFN increased progressively and substantially from early seed filling to beyond harvest maturity in a sigmoidal pattern; 50S in a linear trend in 2012, but plateaued in 2013 from the end of seed filling; seed longevity in a curvi-linear trend (quantified by a polynomial) till harvest maturity; ability to germinate was maximal (100% normal germination) from 15-17 days before to 30-32 days after mass maturity (control). Stopping irrigation before seed filling ended reduced MOW and grain size, but increased HFN, 50S, germinability and seed longevity. Drought resulted in more rapid increase in HFN (14 days after anthesis > 21 DAA > 28 DAA > Control) and earlier attainment of maximum seed longevity. Ear wetting once close to harvest maturity reduced HFN considerably; thereafter it increased, though less than the control. Ear wetting reduced but root wetting increased HFN early in development, whereas both treatments at harvest maturity reduced seed and grain quality. Ear wetting reduced subsequent seed longevity immediately, but a period of re-drying in planta improved longevity - surpassing the control. Ear wetting (25-50mm) once at harvest maturity resulted in greater subsequent seed longevity than wetting for several days or >50mm. Hence direct and indirect and immediate and delayed effects of simulated rainfall were detected; drought improved and rainfall reduced HFN, but seed quality was increased by both.

Master of Science
Department of Animal Sciences and Industry
Terry A. Houser
A total of 48 carcasses were taken from a larger trial using 288 pigs (PIC TR4 × 1050, initially 58.9 kg) in a 73 d feeding study to determine the effects of sorghum dried distillers grains with solubles (S-DDGS) in sorghum- or corn-based diets on ground pork quality. The dietary treatments included: sorghum-based diets with 0, 15, 30, or 45% SDDGS, a sorghum-based diet with 30% corn DDGS (C-DDGS) and a corn-based diet with 30% C-DDGS. Shoulders from 24 barrow and 24 gilt carcasses were ground and evaluated for proximate and fatty acid composition, iodine value (IV), objective color, thiobarbituric acid-reactive substances (TBARS), and sensory attributes. No finishing diet × gender interaction was detected for composition, fatty acid profile, color or TBARS (P > 0.05). Pork from gilts contained less fat and more moisture (P < 0.001), was less saturated with a greater IV and total percentage of PUFA (P < 0.01), and also had a lower L* value (P < 0.001) and higher a* value (P = 0.006) than pork from barrows. Gender did not affect total color change ( E) from 0 to 120 h (P = 0.30), TBARS (P = 0.08), or sensory attributes (P ≥ 0.32). Finishing diet had no affect on total fat, moisture, or protein composition (P ≥ 0.18). Increasing S-DDGS resulted in a linear (P < 0.001) decrease in SFA and MUFA and an increase (P < 0.01) in PUFA and ground pork IV. Pork from pigs fed 30% S-DDGS had a greater percentage of MUFA (P = 0.01) and a lower percentage of PUFA (P > 0.006) and reduced IV (P = 0.03) compared to pork from pigs fed the sorghum-based diet with 30% C-DDGS. Diet did not affect TBARS (P = 0.37) or L*, a*, or b* values (P ≥ 0.11) but was shown to influence E (P = 0.01) with pork from pigs fed sorghum grain and 30% S-DDGS having less total change than all other treatments. It is concluded that consumers will not be able to differentiate ground pork from pigs fed DDGS and that feeding sorghum grain and S-DDGS can be done without affecting ground pork quality.

Changes in ethanol processing have resulted in a reduction of oil in the final coproduct, DDGS, available as a feedstuff. Lowering the oil concentration can decrease the total energy in the diet and, therefore, could affect the animal?s performance. Therefore, we designed two studies where the objectives were to evaluate the influence of grain type and oil concentration of DDGS on finishing cattle performance, feeding behavior, carcass quality, and site of digestion. Our results indicated that steers fed the barley based diet were more efficient as they had a higher gain to feed ratio. Additionally, there were no effects of oil concentration of DDGS on finishing cattle performance or carcass quality. Finally, there were some differences in site of digestion between barley and corn diets however of DM, OM, CP, and starch however, no differences were found when comparing low versus moderate oil concentration DDGS.

Alfalfa may be harvested and used as green feed, pellets, haylage, cubes, hays or matured for seed. The value of the product is determined in part by the yield, costs of production, demand and end usage. The high nutrient composition makes this feed a major component of balanced rations. However, its quality is highly variable from production through harvest, storage and feeding.

Bibliography: leaves 174-192. This research aims to obtain detailed knowledge on the effects of a period of high temperature on the accumulation of grain dry matter and endosperm starch, protein and B-glucan in the developing grain of the malting barley variety Schooner. Bbarley plants are exposed to high temperatures during mid grain filling for 5 days. Grain growth characteristics are measured prior to, during and following the high temperature period, with the aim of characterising the high temperature response in developing grain. The activities of several enzymes and metabolities of the pathway of starch synthesis are monitored and compared to those in grains maintained at a lower temperature. In addition, grain structure is also compared between control and heat treated grain during development, at maturity and following malting.

L’objectiu de la present Tesi Doctoral ha estat contribuir al coneixement existent sobre la formació del rendiment en blat i la qualitat del gra, així com l’efecte que les variables ambientals exerceixen sobre ambdós. Per això, es va analitzar una sèrie històrica formada per 24 genotips de blat dur, representatius dels cultivats a España i Itàlia al llarg del segle passat, i una col•lecció de 20 varietats de blat fariner escollides entre les més cultivades a España durant les últimes dècades i representatives dels 4 grups de qualitat industrial. Es va estudiar l’efecte de l’al•lel enanitzant Rht-B1b sobre la biomassa aèria i radicular i les seves conseqüències sobre la formació del rendiment, els canvis causats per la millora genètica en la qualitat del gra i els patrons d’adaptació (interacció Genotip x Ambient), així com l’efecte de les variables meteorològiques sobre el rendiment, els seus components i la qualitat.
El objetivo de la presente Tesis Doctoral fue contribuir al conocimiento existente sobre la formación del rendimiento en trigo y la calidad del grano, así como del efecto que las variables ambientales ejercen sobre ambos. Para ello se utilizó una serie histórica formada por 24 genotipos de trigo duro, representativos de los cultivados en España e Italia a lo largo del pasado siglo, y una colección de 20 variedades trigo harinero escogidas entre las más cultivadas en España en las últimas décadas y representativas de los 4 grupos de calidad industrial. Se estudió el efecto del alelo enanizante Rht-B1b sobre la biomasa aérea y radicular y sus consecuencias sobre la formación del rendimiento, los cambios causados por la mejora genética en la calidad del grano y los patrones de adaptación (interacción Genotipo x Ambiente), así como el efecto de las variables meteorológicas sobre el rendimiento, sus componentes y la calidad.
The objective of this Doctoral Thesis was to contribute to the existing knowledge of yield and grain quality formation, as well as the effect that the meteorological variables exert on them. For this, an historical series of 24 durum wheat genotypes was used, being all of them representative of those used in Spain and Italy during the last century. Moreover, a set of 20 bread wheat varieties was selected among the most cultivated in Spain during the last decades, which were representative of the four industrial quality groups. The effect of the Rht-B1b dwarfing allele on aerial and root biomass and its consequences on yield formation was assessed. Plant breeding effects on grain quality and adaptation patterns (Genotype x Environment interaction) and the effect of meteorological variables on yield, yield components and quality was also studied.

The quality of wheat-based food. products, especially bread quality, is significantly affected by the characteristics of the wheat flour, both in term of processing quality and nutritional value. White flour, by far the most used flour in breadmaking, derives from grinding of the grain starchy endosperm. Several studies have demonstrated that the endosperm tissue shows significant inhomogeneity in its chemical composition, with both quantitative and qualitative patterns of tissue distribution observed for all its main storage components. This project has focused on a detailed study of the spatial distributions of proteins and starch within the wheat endosperm, how they are influenced by genetic and environmental factors and how they affect the processing properties of the flour. Multiple technologies, including protein/starch chemistry, immunocytochemistry and microscopy, have been used to achieve the research aims. The results show a clear deceasing gradient in total protein in the endosperm from the subaleurone toward the centre of the grain. Strong spatial gradients were also observed in the composition of gluten proteins. These patterns were best visualised in vivo by Immunofluorescence microscopy. The SE-HPLC profiles, which can be used to predict processing quality, also showed gradients across the grain. The pattern of distribution of starch showed an opposite trend to that of proteins, being higher in the central endosperm cells than in subaleurone cells. 1 The amylose/amylopectin ratio also varied spatially in grain of some of the cultivars. Strong genotype effects were found for all parameters that were measured. Nitrogen fertilisation was found to have a strong impact on the amount of protein (both quantity and quality) and their distributions. Moreover, it also influenced, albeit to a much smaller extent, the amount of starch. The detailed information on protein and starch distribution within endosperm and effects of genotype and nitrogen fertiliser from this study provided knowledge that would lead to greater understanding of protein and starch synthesis as well as nutrition transport within grain. It is also potentially beneficial for improving milling technology and selecting breeding candidates for different purposes.

Australia is the fourth largest wheat (Triticum aestivum) exporter around the world,exporting about18 million tonnes annually. To achieve a desirable profit, the focus of the Australian wheat industry is to concurrently increase grain yield (GY) and grain protein content(GPC). However, due to the negative correlation between wheat GY and GPC,this is a challenging task. Apart from complex genetic approaches, modifyingnitrogen and sulphur fertilizer regime is a strategic method to achieve this goal. It is known that without adequate sulphur application, wheat cannot reach its full yield potential and make efficient use of nitrogen for protein biosynthesis. During grain filling, changes in nitrogen availability mainly affect GPC, while variable sulphur concentration exerts major impact on grain protein compositions. In this study, the impacts of a range of nitrogen and sulphur treatments on a series of nitrogen use efficiency (NUE) related agronomic traits, morphological traits and protein parameters were investigated using multi-year & site field trials and glasshouse experiments, and the accumulation patterns of individual storage protein composition. Six varying quality Australian bread wheat varieties,including Spitfire, Mace, Wyalkatchem, Westonia, Bonnie Rock,and Livingston,were selected for this study. Grain protein yield is used as a parameter to represent protein efficiency which is obtained by GY multiplying GPC. The results indicate that nitrogen application increases grain protein yield and optimizes grain protein parameters, but the NUE in relation to GY and grain protein yield (NUE-GY & NUE-PY) are both decreased. The correlation of neck diameter with GY and NUE-GY under different nitrogen treatments indicates that the improvement of neck diameter can be achieved through optimizing nitrogen treatments, which ultimately increases GY and NUE-GY. Wheat GY and GPC react to the nitrogen availability at the similar level with the GY being slightly more sensitive, and genotype is a vital determinant of grain protein yield. In another hand, high sulphur application can increase GY and NUE-GY simultaneously. All peduncle traits are positively correlated with GY and NUE-GY under different sulphur treatments, indicating that peduncle trait enhancement is a route for GY and NUE-GY appreciation through high sulphur availability. To understand the impact of nitrogen availability on grain protein biosynthesis during grain filling, the GS activity and SDS-unextractable polymeric proteins (UPP)accumulation in high and low nitrogen treatments were studied, followed by a comparative proteomics study to identify major functional proteins in response to nitrogen availability using developing grains at7, 14, 21,and 28 days post-anthesis (DPA). The results illustrate that glutamine synthetase (GS) activity of developing grains is flag leaf dependent, and high nitrogen application improves protein polymerization to form UPP. Its underlying mechanism was revealed by comparative proteomics study and validated by yeast two-hybrid assay, which shows that PPIase can be SUMOylated with the assistance of SUMO1, and high nitrogen availability facilitates this connection for subsequent protein polymerization. Since fertilizer management exerts major impacts on gene expression, a comparative transcriptomic study was carried out to explore the role of sulphur in regulating gene expression for nitrogen metabolism and grain protein biosynthesis. Eighteen developing grains at7, 14,and 21 DPA from high and low sulphur treatments were collected for RNA-seq assay. The results indicated that high sulphur supply led to one upregulated differentially expressed gene (DEG)and 63downregulated DEGs in 7 DPA. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway enrichment analysis showed that three of 63downregulated DEGs were significantly enriched in nitrogen metabolic pathway, and all annotated as GS, which is the pivotal enzyme in GOGAT cycle for nitrogen assimilation, revealingthat GS is a bridge of sulphur and nitrogen metabolism. Accordingly, the dynamics of GS activity were traced and compared between high and low sulphur treatments.Results indicate that high sulphur availability results in an increased GS activity of developing grains. Meanwhile, the transcriptomics assay of the developing grains from high and low sulphur treatments identifies a total of 20,997 DEGs in four libraries, and there are 1,004 DEGs enriched in significant GO items and KEGG pathway. After aligning their promoter regions with an in-house developed cis-regulatory elements database, 40 cis-regulatory elements in response to phytohormone were identified and most of them show response to ABA. Subsequently, with the use of on-line database WheatNet, a sulphur-dependent epigenetics regulatory mechanism for wheat seed storage proteins biosynthesis was proposed, which suggests that high sulphur availability induces HMT-1 expression for methionine (Met) biosynthesis for an increased amount of Met for grain storage protein (20% Met) and secondary metabolites biosynthesis (80% Met). It also maintains redox homeostasis for protein polymerization. The proposed network was validated by the comparison of free amino acid dynamics between high and low sulphur treatments during grain filling, revealing that high sulphur availability can take advantage of more free amino acids to participate in biological processes for grain growth than low sulphur availability. Specifically, high sulphur application results in reduced asparagine residuals of mature grain (42 DPA), which will potentially decrease the acrylamide formation during breadmaking and thus reducethe chance of cancer development in human. In conclusion, this study demonstrates that although an incremental nitrogen application can increase GY, GPC,and grain protein yield, the NUE-GY and NUE-PY are decreased.High sulphur availability can increase GY and NUE-GY simultaneously. Finally,a nitrogen regulatory mechanism and a sulphur dependent mechanism of wheat grain protein polymerization were respectively revealed byproteomics study and transcriptomics study.

Application of nitrogen (N) fertilizer in conjunction with the irrigation event occurring closest to the flowering stage is effective in reducing the incidence of yellowberry and boosting grain protein levels of durum wheat. However, N applications at this time normally do not increase grain yield, except perhaps on very sandy soils. A field experiment was conducted to determine the profitability of applying 35 pounds of N per acre at flowering to durum wheat to avoid dockage for poor grain quality. Two treatments consisted of a check plot with no N applied at flowering and UAN 32 water run at a rate of 35 lbs. N /acre to basin irrigated durum wheat grown on a loamy sand soil. Maximum durum wheat grain yield (6157 lbs. /acre), protein concentration (13.7 %), and corrected income per acre ($480.31) was obtained with the N fertilizer application. In fact, N fertilization at flowering on this sandy soil increased durum wheat grain yield by 255 lbs. /acre compared to the unfertilized plot.

Experiments were conducted in Avra Valley, Arizona, to study the use of digested liquid sewage sludge as a source of plant nutrients in the commercial production of grain and straw from wheat. Wheat grown with the recommended amount of plant -available nitrogen from sewage sludge produced the same grain yield as wheat grown with the same amount of nitrogen from inorganic fertilizer. Wheat grain and straw grown with sewage sludge and inorganic fertilizer had similar livestock feeding qualities. Fertilizing wheat with sewage sludge delayed maturity.

Kenaf was grown as a hay crop in Mohave Valley to determine its growth characteristics, hay yield, and feed quality. The first cutting occurred 75 days after planting when plants were approximately 30 inches tall and had 30 nodes. Hay tonnage was only 1,000 lbs dry matter/acre, crude protein was 20.7 %, ADF was 40.2 %, and TDN was 57.5 %. Forage quality was adequate for beef cattle and sheep.

Thesis (Ph.D.)--University of Adelaide, School of Earth and Environmental Sciences, Discipline of Soil and Land Systems, 2004.
"November 2004" Includes bibliographical references (leaves 182-189). Also available online.

In order to investigate the effects of elevated temperatures during grain development on seed quality, a series of experiments was carried out under both controlled environment and glasshouse conditions. Plants of several cultivars of barley (Hordeum vulgare L.) were subjected to different temperature regimes (18^oC, 30-18^oC, 30^oC and 18-38^oC) during grain development and, after harvest, the seeds were tested for vigour. Grains which had experienced elevated temperatures for part or all their developmental period were lighter and had smaller embryos than grains which experienced 18^oC for most or all of their developmental period. There was a significant positive correlation between grain dry weight, and embryo dry weight. When eleven genotypes were grown in a glasshouse at approximately 18^oC/13^oC (day/night) and a day length of 18 h, grain dry weight and embryo dry weight varied according to genotype. Genotypes with heavier grains had larger embryos than those with lighter grains. Germination tests were carried out using 5ml of distilled water per 100 grains. The germination of grains grown in all temperature regimes was > 94%. Grains which had experienced elevated temperatures during grain development had a higher percentage germination in tests using 8 ml and 10 ml of water per 100 grains than grains which had experienced 18^oC throughout grain development. Seedlings from grains grown in elevated temperatures had fewer roots and had seminal roots which were shorter than those of seedlings from grains which had experienced low temperature throughout development. It was found that plumule lengths were either similar in all seed lots, or that seedlings from grains grown at elevated temperatures had longer plumules than those from grains grown at 18^oC. When seeds were planted at depth of 4 cm in fine sand in pots, seedlings from grains grown at elevated temperatures emerged earlier than those from grains grown at 18^oC.

Agronomic, genetic and environmental influences on oat grain quality were investigated. Nitrogen application at the boot stage of crop development did not generally affect physical characteristics of oat grain. Groat protein content increased with the application of nitrogen at the boot stage of crop development but oil content tended to decrease while $ beta$-glucan content was generally not affected. Delayed seeding usually reduced oat grain quality and usually increased protein and $ beta$-glucan contents. Heritability of $ beta$-glucan content, groat percentage and rust resistance were all low; hence, breeding to improve these traits may be difficult. Results of experiments on the inheritance of $ beta$-glucan were not conclusive but it appears that $ beta$-glucan content is under the influence of the endosperm genome. Genotype by environment interactions were significant for grain yield and for protein, oil and $ beta$-glucan contents. The cultivars Ultima and Sylva were superior in mean grain yield across environments compared to other cultivars. The cultivars Laurent and Nova were superior for mean protein content across environments and the cultivar Marion QC was superior for mean oil and $ beta$-glucan contents. AMMI (Additive main effects and multiplicative interaction) analysis would be favoured over the other genotype by environment analyses used in this study because AMMI afforded more information about the genotype by environment interactions.

The effect of natural and simulated rainfall during seed development and maturation on wheat (Triticum aestivum L.) seed quality development, particularly changes in subsequent air-dry longevity (stored hermetically at 40°C with 15% moisture content), was investigated in poly-tunnel (2010) and field experiments (2011 and 2012). Avoiding rain during seed development and maturation accelerated the rate and reduced the duration of seed filling and thus reduced final seed weight, while increase in rainfall slowed down the rate and increased the duration of seed filling and increased seed weight in wet and cold weather (2011), but dry and warm weather (2012) had the opposite effect. Maximum germination of seeds dried after harvest was attained at 39-49 days after anthesis (DAA) and maintained throughout until 70 DAA. Seeds not dried attained ability to germinate slightly later with subsequent fluctuations, probably associated with dormancy. Potential longevity increased during this period, reaching a maximum at 53-56 DAA, coinciding with harvest maturity, and then declining in 2012 but not in 2011. Wetting ears reduced longevity at all stages of seed development when seeds were harvested soon after the event, and more so after two wettings, but considerable recovery in subsequent longevity occurred when seeds were harvested after 1 or 7 days re-drying after wetting. Reduction in rainfall significantly reduced crude protein and the incidence of blackpoint in both years. Hagberg Falling Number (HFN) decreased in 2011, but increased in 2012, perhaps due to wetter and cooler conditions in 2012. Rainfall affected seed quality development but the extent of damage varied amongst developmental stages, being greater at later developmental stages although considerable ability for recovery with re-drying was noted. Rainfall had a negative effect on most of grain quality parameters except crude protein concentration.

Expenditure on wheat importation in sub-Saharan African countries is increasing greatly arising from the region’s rapidly expanding human population, urbanisation, and unfavourable conditions for wheat cultivation. Adoption of composite flours is encouraged to reduce wheat importation and promote local agriculture. Barley brewer’s spent grain (BSG), a high-fibre by-product of the brewing industry, is relatively inexpensive and available at large quantities. Sorghum, which is well-adapted to cultivation in sub-Saharan Africa, is an underutilized grain-crop. BSG and sorghum are potential vehicles for producing less expensive bread of improved nutritional properties. However, both lack functional gluten, which is responsible for good viscoelastic dough and high bread volume. BSG particle size reduction in combination with a sourdough fermentation were investigated as BSG pre-treatment technologies to improve wheat-BSG composite dough and bread quality. Fractionation of dried BSG through roller milling enriched the protein of BSG flour, but gave poor loaf volume and denser crumb. Additionally, the much lower flour extraction yields compared to hammer milling which gives a 100 % extraction rate flour would impact negatively on the product economic viability. Mixolab dough rheology showed that a 15 % BSG substitution significantly increased dough development time and flour water absorption. However, application of a short (3 h) ‘sponge and dough’ sourdough process improved the gas-holding properties of composite, increased loaf volume and crumb softness compared to a straight dough method. At 20 % BSG substitution, the composite wheat bread had 71.4 % more dietary fibre as well as higher protein and mineral contents than a commercial wheat brown bread. The effects of chemical (using glacial acetic acid) and physical treatment (through sheeting) on the functionality of sorghum doughs from normal and transgenic high protein digestibility (TG-HD) lines with supressed ?-kafirin expression were investigated. Normal sorghum flour doughs were subjected to sheeting in combination with sourdough addition. Partial flour pre- gelatinization, by cooking, was a pre-requisite for formation of a cohesive dough and was hence applied throughout this study. Upon baking, the combination of sheeting (15 passes) and sourdough addition (50% w/w of total flour) produced bread with a more aerated crumb and greater volume compared to the untreated control. Tensile tests of TG-HD doughs showed 38 and 42 % higher extensibility, compared to their null control doughs. These effects were attributed to the greater accessibility of ?-kafirins in the invaginated protein bodies of these high protein digestibility lines. Shear forces applied by manual sheeting and glacial acetic acid treatment were used in attempt to free the protein body-encapsulated kafirins and hence functionalise them in sorghum dough. Transmission electron microscopy (TEM) of these doughs revealed successful disruption of protein bodies by the respective treatments. Starch granules observed by scanning electron microscopy (SEM) seemed to remain intact, indicating the effects to be protein-related. However, the elevated temperature (>50oC), glacial acetic acid treatment and combination thereof, reduced dough extensibility. This was possibly due to the presence of other components in the dough system apart from the kafirins, mainly the starch granules, as well as insufficient plasticisation. The study shows that a combination of physico-chemical treatments, with emphasis on functionalising inert components such as fibre and protein, can substantially improve the dough functionality and consequent bread quality of gluten-void cereal grain materials.
Dissertation (MSc (Agric))--University of Pretoria, 2017.
Food Science
MSc (Agric)
Unrestricted

[Abstract]: This dissertation investigates how an independent Australian grain exporting SME has been able to access the Japanese market for food quality soybeans and corn. This firm has succeeded in entering this market despite entrenched competition from traditional suppliers in the USA and Canada and in the face of rigorous food safety and quality standards as required in this particular market. The research in this dissertation focuses on outlining the critical ‘enabling competencies’ that the firm and its suppliers developed in order to enter the Japanese market. A single case methodology involving multiple in-depth interviews with key stakeholders was used to provide triangulated evidence concerning the necessary and sufficient conditionsfor SME exporters to compete successfully in such mature markets, particularly in the face of entrenched competition from large scale suppliers of similar productsfrom the United States and Canada. From the data collected in this research, a model of SME internationalisation was proposed highlighting the driving forces whichstimulated the development of a set of ‘enabling competencies’ enabling successful entry into the Japanese market for food grains. This model has both practical andtheoretical implications for the development of trade between Australia and Japan in the food grain sector. In conclusion this dissertation suggests that firms with thecapacity to develop such competencies can succeed in entering enter such productmarkets.

Master of Science
Department of Agronomy
Ramasamy Perumal
Tesfaye Tesso
Grain mold (GM) is an important biotic constraint limiting yield and market value of sorghum grains. It results in kernel discoloration and deterioration. Such kernels have reduced seed viability, low food and feed quality. Breeding for grain mold resistance is challenging because of the complex nature of host-pathogen-environment interactions. This complex task could be made simpler by utilizing molecular markers. Utilization of marker resources may help to find genomic regions associated with grain mold resistance. In this study, three sets of field and laboratory based experiments were performed which will help in finding potential grain mold pathogens responsible for kernel deterioration in the studied environment and search for genotypes with better kernel quality and grain mold resistance. In the first part of the study, in vitro screening of 44 grain mold resistant sorghum genotypes developed and released by Texas A & M AgriLife Research. This study was aimed at identifying sources resistance to grain mold infection through laboratory screening. The result revealed that genotypes Tx3371, Tx3373, Tx3374, Tx3376, Tx3407, Tx3400, and Tx3402 were have high level of resistance and were identified as potential sources of grain mold resistance as each showed minimal fungal infection and higher grain quality traits. The second experiment was performed to optimize surface sterilization protocol for the extraction of fungal pathogens from the kernel surface (pericarp) and to study the effect of bleach percentage and time period on pathogen extraction. Seven treatments using sterilized double distilled water (0 % bleach (v/v)) and different bleach (NaOCl) concentrations (2.5, 5, 7.5, 10, 12.5 and 15 %) were used with a time interval of 2.5, 5, 7.5 and 10 min. Optimized surface sterilization in the range of 7.5 to 15 % bleach (v/v) for 7.5 to 10 min resulted least contamination and fungal genera isolation from the surface of the kernel. The third study was aimed at characterizing genotypes (sorghum association panel) for grain mold pathogen F. thapsinum and by using genome wide association (GWA) tool in order to find genomic regions associated with grain mold resistance. We studied the effect of different agronomic and panicle architecture traits on grain mold incidence and severity. Effects of grain mold on kernel quality traits were also studied. We reported two loci associated with grain mold resistance. Based on first year field screening results, 46 genotypes having grain mold ratings 1-5 (1 = < 1% panicle kernel molded; 5 = > 50% panicle kernel molded) were selected for a detailed study aimed at understanding grain mold x fungal pathogen interactions to physical and chemical kernel traits. Seed germination test, vigor index, and tetrazolium viability test were performed to study effect of grain mold infection on kernel viability and vigor. Alternaria, Fusarium thapsinum, F. verticillioides and F. proliferatum were the main fungal genera isolated from bisected kernels. Based on two year screening, SC623, SC67, SC621, SC947 and SC1494 were most resistant based on both PGMR and TGMR rating while SC370, SC833, SC1484, and SC1077 showed the most susceptible reaction and this was consistent for individual location analysis. SC309, SC213, SC833, SC971 and SC1047 are genotypes having identified loci for grain mold resistance.

Lysine deficiency is a major nutritional problem faced by poor people living in the arid and semi-arid tropics who depend on sorghum as their staple food. This is because of poor lysine content and digestibility of sorghum proteins, which aggravates when sorghum is cooked in food. To address this nutritional problem, compositing with locally available lysine-rich legumes has been proposed. Therefore, this study investigated the effects of compositing with the African grain legume, cowpea, on the protein and functional quality of important traditional African sorghum foods. Two sorghum cultivars, a red, tannin (NS 5511) and a white tan plant, non-tannin (Orbit) composited with cowpea at 70:30 ratio, were used to prepare three traditional sorghum foods, ugali (unfermented thick porridge), uji (fermented thin porridge) and injera (fermented flatbread). The protein quality of the traditional sorghum foods was determined by measuring their protein contents, lysine and reactive lysine contents, and in vitro protein digestibility. The functional properties of the foods were studied using instrumental texture analysis. Other sensory properties of ugali were determined using a trained sensory panel. Compositing with cowpea increased the protein contents of the foods by up to 35% and 57% for NS 5511 and Orbit foods, respectively. Lysine contents of the food proteins increased by 67% to 139%. Reactive lysine content increased by 10% to 75%. Protein digestibility of the foods increased by 13% to 62%. There was approximately three- and two-fold increase in protein digestibility corrected amino score (PDCAAS) of NS 5511 and Orbit foods, respectively, due to addition of cowpea. However, Orbit-plus-cowpea foods still had better protein quality than NS 5511-plus-cowpea foods, primarily because of the tannins in the latter which bind the proteins thereby lowering their digestibility. Compositing reduced paste peak viscosity (PV) and cool paste viscosity (CPV) of uji porridge by 6% to 23%, and 6% to 12%, respectively, probably as a result of decreasing porridge starch content. Principal component analysis (PCA) showed that compositing contributed 38% of the variation in 17 sensory attributes of ugali. Compositing imparted cowpea flavour to ugali. Most of the variation in sensory properties (59%) of ugali was due to the quality characteristics of the sorghum cultivars. Compositing increased the stiffness of NS 5511 injera by up to 25%, while it reduced the stiffness of Orbit injera by up to 12%. These differences in stiffness suggested a weakening effect of weaker H-bonding between tannins and other food polymers such as proteins instead of stronger covalent bonds like those involved in proteins-protein interactions. Compositing important traditional sorghum foods with cowpea has potential for helping to solve lysine deficiency faced by sorghum consumers in the semi-arid tropics. However, it introduces cowpea flavour which may need to be eliminated, in foods intended for consumers not accustomed to cowpea flavour. Copyright
Dissertation (MSc)--University of Pretoria, 2009.
Food Science
unrestricted

Durum wheat is a type of wheat primarily used for pasta production. North Dakota is the leading producer of durum wheat in the US with average yields of 2700 kg ha-1. Durum wheat price discounts are common and occur due to disease, heavy metal contamination, and environmental issues that impact grain quality. Studies were conducted in order to determine how agronomic approaches might impact durum quality. Experiments were conducted in order to determine what impact planting date, cultivar, and seeding rate had on the agronomic performance and quality of end-use traits. In general, a delay in planting date resulted in a significant decrease in yield and test weight for all cultivars. Cultivars differed for many of the end-use traits evaluated such as protein content, falling number, and vitreous kernel. Seeding rate had little impact on the traits evaluated. No combination of planting date and cultivar was identified that consistently resulted in grain marketed as US Grade 1 hard amber durum (HAD), or ?choice durum?. Cultivar selection remains the best option for maintaining end-use traits. The effect of Zn fertilizer source and placement on grain Cd were evaluated. Treatments evaluated had no negative impact on grain yield or test weight. The foliar application of 1.1 kg Zn ha-1 Zn-EDTA in combination with 33 kg N ha-1 in the form of UAN applied at Feekes 10 growth stage (boot stage) resulted in the lowest grain Cd, and highest grain Zn, Fe and protein and represents an approach of biofortification for durum wheat.
North Dakota Wheat Commission