Tesi sul tema "Barley"

The assessment of barley and malt quality for a barley breeding program was revised. The small size of the samples available in breeding requires the development of special methods that may differ slightly from those used by the malting and brewing industry when dealing with much larger samples of grain. Small-scale methods for malt extract determination were investigated. A new method using 1 g of malt in a 10 M1 mash was proposed for use in barley breeding. Near infared methods for barley and malt analysis were studied. Methods for distinguishing barley and malt varieties. A system for capture and storage of data and analysis of results by computer was developed specifically for a barley quality laboratory supporting a barley breeding program.
Masters of Applied Science

Bibliography: leaves 183-211. This study evaluates the backcross breeding method for the introgression in barley of agronomically important traits into a malting quality background using molecular markers.

Thesis (MTech (Horticulture))--Cape Peninsula University of Technology, 2018.
This study evaluated the effects of 5 different soaking treatments in conjunction with 5 varying irrigation intervals on the germination, growth and nutritional values of seed of Hordeum vulgare Sv13. The 5 different soaking times consisted of 1, 3, 8, 16 and 24 hours. The barley seed was first cleaned and then placed in a vessel containing 500 ml of distilled water with a 20 % solution of sodium hypochlorite (bleach) at room temperature. Thereafter the pre-soaked seeds were transferred to a perforated container, containing no medium and placed into a growing chamber equipped with drip irrigation. The seed was then irrigated with 1245 ml of water at 5 different intervals namely every 2, 4, 8 10 and 12 hours. The temperature of the hydroponic growing room was kept at a constant 23 °C using a hotoperiod of 16-hour day/ 8-hour darkness. The seed was allowed to germinate and grow for a period of 8 days before being harvested. The objectives of this study were to determine the most beneficial combination of soaking treatment in conjunction with the most beneficial irrigation interval on the germination rate of the seed allowing for radicle emergence and coleoptile production. It was also used to determine which combination of treatments was most beneficial to the growth and nutritional values of the seed post-harvest. Another objective was to ascertain the shortest soaking time for application in a small-scale, hydroponic growing unit as well as the frequency of irrigation required to grow seedlings, thereby determining the amount of water required to produce a seedling mat for a small-scale, subsistence farmer, with the emphasis being on water reduction. Each treatment was replicated 10 times and consisted of 500 grams of seed, which when placed into its container measured 2 centimetres in depth, totalling 25 treatments in all. Germination was measured by observing radicle emergence in the first 2 days of the growing period first after a 24-hour cycle and again after 48 hours. The numbers of leaves present at harvest after an 8-day growing period were also counted to determine germination rate of the seeds. Growth was determined by average leaf height as well as the tallest leaf on day 8 of the growing cycle. Root mat expansion was also measured, post-harvest, which was compared to the initial 2 cm planting depth of seed. Wet and dry weights of the plant material were measured post-harvest. Samples of the harvested material were also sent for nitrogen and protein analysis. It was discovered that most of the results favoured a shorter soaking time and an increase in irrigation frequency, bar a few exceptions. Most favoured a pre-soaking time of only 1 hour together with an irrigation frequency of between 2 and 4 hours. This shows that small-scale farmers would be able to reduce the time spent on soaking of their seed. Although the frequency of the irrigation interval remained high further testing would be required to determine if the amount of water applied at each irrigation interval could be reduced and still produce favourable results. It would also remain to be seen if no irrigation during the 8-hour dark photoperiod would have any negative impact on germination, growth and nutritional values of the seedlings.

Barley yellow dwarf virus (BYDV), an aphid transmitted luteovirus, is the most widespread and economically damaging virus of cereal crops. The work in this thesis aims to characterise the basis of the naturally occurring resistance to BYDV in cereals in three ways: Firstly, by facilitating the isolation of the Yd2 gene for BYDV resistance from barley by a map-based approach. Secondly, by determining if a BYDV resistance gene in rice is orthologous to Yd2. Thirdly, by establishing if other BYDV resistance genes in non- Ethiopian barleys are allelic to Yd2. It is hoped that the information generated in this study will ultimately assist in the production of BYDV resistant cereal cultivars. A detailed genetic map of the Yd2 region of barley chromosome 3 was constructed, containing 19 RFLP loci, the centromere and the Yd2 gene. Yd2 mapped on the long arm, 0.5 cM from the centromere, and in the mapping population of 106 F2 individuals, perfectly cosegregated with the RFLP loci XYlp, and Xwg889. This map represents the first stage in a project to isolate the Yd2 gene by a map-based approach. The isolation of Yd2 could help to elucidate the molecular mechanism of the Yd2-mediated BYDV resistance, and may allow the production of BYDV resistant cereals by genetic transformation. The RFLP markers mapped closest to Yd2 could also be useful in barley breeding, by enabling selection for both the presence of Yd2 and the absence of agronomically undesirable traits known to be closely linked to Yd2. Genetically Directed Representational Difference Analysis (GDRDA) is a technique based on subtractive hybridisation, which can be used to identify RFLP markers closely linked to a gene of interest. Two GDRDA experiments were performed with the intention of generating additional RFLP markers close to Yd2. However, the first experiment yielded RFLP probes that were not derived from the barley genome, while the second experiment yielded probes that detected repetitive sequences. It was concluded that GDRDA is of limited use in generating further markers close to Yd2. To isolate the Yd2 gene by a map-based approach, a much larger mapping population will need to be analysed to genetically resolve markers tightly linked to Yd2. If the two morphological markers uzu dwarf and white stripe,,j flank Yd2, then they could assist in this task by enabling the visual identification of F2 seedlings resulting from recombination close to Yd2. However, in this study, both morphological markers were found to be located distal to Yd2. Therefore, these two morphological markers can not be used together to facilitate high resolution genetic mapping of the Yd2 locus. It may be possible to use large-insert genomic DNA clones from the relatively small genome of rice to generate further RFLP markers close to the Yd2 gene in barley, provided that the order of orthologous sequences in barley and rice is conserved close to the Yd2 locus. To assess the feasibility of this approach, RFLP probes used to identify loci close to Yd2 were mapped in rice using a segregating rice F2 population. Five of the RFLP loci mapped together and in the same order as RFLP loci mapped close to Yd2 in barley using the same probes. By comparing the location of RFLPs mapped by other researchers in rice using probes mapped close to Yd2, the region of conserved linkage between rice and the Yd2 region was tentatively identified as the central portion of rice chromosome 1. The collinearity shown by orthologous sequences in barley and rice indicated that it may indeed be possible to use rice to assist in generating RFLP markers close to Yd2. Of all the cereals, rice is the most amenable to map-based gene isolation, due to its small genome, well developed physical and genetic maps, and its ability to be genetically transformed with high efficiency. If a BYDV resistance gene that is orthologous to Yd2 could be identified in rice, this gene could be isolated with relative ease, and then used to identify barley cDNA clones corresponding to Yd2 gene by virtue of the sequence homology expected between these genes. To test if a BYDV resistance gene from an Italian rice line is orthologous to Yd2, recombinant-inbred rice lines previously characterised for this gene were analysed using probes mapped close to Yd2 in barley. No genetic linkage was detected between the RFLP loci and the BYDV resistance gene, indicating that the gene is unlikely to be orthologous to Yd2. BYDV resistance alleles at the Yd2 locus which are of a non-Ethiopian origin may show interesting differences to Ethiopian Yd2 resistance alleles. To identify barleys which may contain resistance alleles of Yd2, ten BYDV resistant barleys not known to contain Yd2 were assessed for their resistance to the PAVadel isolate of BYDV in the glasshouse. CI 1179, Rojo, Perry, Hannchen, Post and CI 4228 were found to be the most resistant under these conditions, and were analysed further. If the resistance from these barleys is controlled by alleles of Yd2, RFLP markers close to Yd2 will be expected to cosegregate with the resistance in F2 families derived from crosses between these resistant barleys and the BYDV susceptible barleys Atlas and Proctor. RFLPs suitable for use in these allelism tests were identified using probes mapped close to Yd2. However, time did not permit the analysis of these F2 populations.
Thesis (Ph.D.) -- University of Adelaide, Dept. of Plant Science, 1996

In the northeastern United States, craft beer is on the rise. With local brewing increasing, the supply of local raw materials becoming an urgent problem in some northeastern states, like Michigan, New York, Ohio, Pennsylvania, and Vermont. The overall goal of the project is to determine which cultivars are best adapted to specific regions in the northeastern United States, and to detect the impact of different environment factors on the barley genotypes. In general, cultivars from Europe had better resistance to pre-harvest sprouting (PHS) and lower beta-glucan levels than two-rowed cultivars developed in North America. The varieties, Explorer, LCS Genie, LCS Odyssey, KWS Fantex, and KWS Beckie are candidates for production in the eastern United States because of their higher levels of resistance to PHS and malt extract, and their lowers levels of beta-glucan.

Plant growth regulator(s) (PGR) can be used as lodging inhibitors and/or yield promoters for spring barley (Hordeum vulgare L.). From 1987 to 1990 four field experiments were conducted to monitor barley main-stem apical development and to determine the effects of chlormequat (CCC) and ethephon on the development, physiology and yield of spring barley. Our data provide a description of barley apical development and the general pattern of leaf and spikelet primordium production under field conditions. In general, PGR treatment reduced the apical dominance of dominant sinks allowing the survival and greater development of more subordinate sinks. Early application of either CCC or ethephon retarded development of the main-stem apex from shortly after application to the awn elongation stage and reduced the number of aborted spikelet primordia, thus increasing the potential number of grains per spike and sometimes grain yield. Ethephon applied at ZGS 39 reduced plant height and lodging. Early application (ZGS 30) of ethephon, alone or in combination with CCC increased the number of spikes m$ sp{-2},$ but not grain yield. The number of spike-bearing shoots per unit area or per plant was increased by early PGR treatment, primarily by enhancement of tiller number rather than tiller survival. Early application of CCC or ethephon to spring barley is not justified, and caution must be taken when using ethephon at the currently recommended rate and stage for lodging control. Post-anthesis application of ethephon can efficiently enhance grain fill and yield of spring barley.

On title page "B" is superscript. Bibliography: leaves 112-135. The primary aims of the work described in this thesis were to isolate and characterize the cDNAs that correspond to the two B-glucan exohydrolases designated isoenzyme ExoI and isoenzyme ExoII. (abstract)

Three experiments were carried out to evaluate the applicability of the intensive management system to barley production in Quebec. In the first experiment, the effects of three levels of nitrogen fertilizer and ethephon (Cerone) on the performance of cultivars were tested. The aim of the second experiment was to test the effects of fungicide application and row width. In the third experiment, conventional and intensive management techniques were tested on three soil types.
High levels of nitrogen increased the grain protein content and thus improved the feed quality of spring barley. Application of ethephon reduced plant height but also reduced the number of grains per head. A fungicide by row width interaction resulted in a reduced seed size and weight in the narrow rows. The effects of intensive management on yield were inconsistent and were influenced to a large extent by the prevailing weather and soil conditions.

Multi environment trials conducted over mapping population are often used to test genotypes in a set of environments that represent the target environmental range. The first part of this work is the evaluation of the ‘Nure’ x ‘Tremois’ double-­‐haploid mapping population, together with an association panel comprising 185 barley varieties representative of the barley germplasm cultivated in the Mediterranean basin. Plant material was tested across eighteen site by year field trials combination, in six countries across the Mediterranean basin. Trials were growth at sites contrasting for natural rainfall (high vs low on the base of past meteorological data) or at the same site with one being rainfed and the other with supplementary irrigation. Trials conducted for two years in each one of the sites and this allowed tocollect a huge data series comprising agronomical traits defining grain yield and yield components, phenological and environmental data, subsequently used to identify genomic regions involved in barley adaptation. The 118 doubled haploid lines of the mapping population were genotyped with Diversity Array Technology® (DaRT) marker assay and subsequently a total of 15 CAPS and SSCP marker for candidate genes involved in phenology regulation and abiotic stress response were added to the linkage map based on DaRT markers. Data collected were firstly used to perform QTLs analysis with composite interval mapping for any environment/ trait combination, results showed eight QTLs for grain yield, days to heading and grain yield components. . The two mostly frequents QTLs for grain yield and days to heading were located on barley chromosome 1H (3 trials), 2H (8 trials) and 5H (5 trials) overlapping respectively HvFT3 gene, the earliness per se locus (eam6/Eps-­‐2) and the vernalization gene Vrn_H1. A further QTL multi-­‐environment analysis was performed and revealed that across the 18 field trials QTL for eam6/Eps-­‐2 (2H) and Vrn-­‐H1 (5H) were commons for days to heading and grain yield. We use all the environmental information collected to check QTLs sensitivities to co-­‐environmental co-­‐variables. Most of significant associations collected were related to temperature and temperature-­‐based variables troughtout the growing cycle. Eam6/Eps-­‐2 showed non-­‐crossover QTL.E interaction, while for Vrn-­‐H1 crossover interactions were revealed. The 185 barley accession were genotyped with 1536 SNPs and data collected for this population for cold resistance in two field trials in Spain an Italy, the first trial was characterized by an exceptional winter, while the second was previously know has frost-­‐prone environment. Results from genome wide association analysis showed 13 positive associations with specific genomic regions. Interestingly several of these QTL were coincident with the position of previously mapped loci for cold tolerance, on chromosomes 2HL, 4HL and 5HL.
Els assajos en localitats múltiplas de poblacions de mapeo s'utilitzen freqüentment per a testar genotips en un conjunt d'ambients representatius de la condicions climàtiques on es volen introduir aquests genotips. La primera part d'això treball ha estat l'avaluació de la població de mapeo ‘Nure x Tremois’ constituïda de 118 de doble haploides d'ordi, juntament amb panell d'associació que comprèn 185 varietats d'ordi representatives del germoplasma conreat en la conca Mediterrània. El material vegetal ha estat assajat en una combinació de divuit camps per any desllorigats en sis països de la conca mediterrània. Els assajos s'han portat a terme en camps amb diferent disponibilitat d'aigua, classificats sobre la base de les dades relatives a les freqüència i quantitat de les precipitacions o en el mateix lloc amb un camp en secà i altre regat. Els assajos es van portar a terme per dos anys en cada localitat i això va permetre la recollida d'un gran volum de dades que comprenen caràcters agronómicos relacionats amb rendiment i components del rendiment, dades fenológicos i ambientals. Aquestes dades es van utilitzar després per a la identificació de regions genomicas involucrades en l'adaptació de l'ordi a l'ambient. Els 118 dobles haploides de la població ‘Nure x Tremois’ es genotiparon amb marcadors DaRT (Diversity Array Technology), després un set de 15 marcadors CAPS I SCCP per a gens candidats involucrats en la regulació de les fases fenológicas van ser afegits al mapa de lligament construït amb els marcadors DaRT. Les dades van ser utilitzats per a fer una anàlisi de QTL amb procediment ‘Composite Interval Mapping’ para cada combinació ambienti/ caràcter. Es van trobar diversos QTLs per rendiment i data d'espigolat i components del rendiment. Els QTL mes freqüents trobats per rendiment i data de floració i components del rendiment estan localitzats en els cromosomes 1H (3 camps), 2H (8 camps) i 5H (5 camps) coincidents respectivament amb HvFT3 locus, eam6/Eps-­‐2 (earliness per se) locus i amb el locus de vernalización Vrn-­‐H1. Una ulterior anàlisi de QTL feta amb el mètode “Multi Environment Trial” ha revelat que els QTL localitzats en el locus eam6/Eps-­‐2 (cromosoma 2H) i Vrn-­‐H1 (cromosoma 5H) són comunes per rendiment i data de floració en els 18 camps d'assaig. Per això utilitzem tots el dades ambientals col·leccionades durant tot el cicle del cultiu per a investigar la sensibilitat de dites QTL a les co-­‐variables ambientals. La majoria de les associacions oposades estan relacionades amb temperatures i variables relacionades amb aquestes. Eam6/Eps-­‐2 mostra una interacció de tipus quantitatiu amb aquestes variables mentre Vrn-­‐H1 mostra una interacció de tipus qualitatiu amb aquestes variables. Les 185 varietats assajades van ser genotipadas amb 185 SNPs i fenotipadas per resistència a fred en dos assajos uneixo a Espanya i altre a Itàlia. El primer assaig va ser caracteritzat per un hivern excepcionalment fred, mentre el d'Itàlia ha estat utilitzat en passat per testar resistència a fred a causa de els hiverns rígids que solen registrar-­‐se en aquesta localitat. Les dades van ser utilitzats per a portar a terme la analisis GWAS “Genome Wide Association Analysis” . Els resultats van permetre identificar 13 regions genomicas involucrades en la resistència a frio. Entre elles tres regions coincideixen amb loci ja mapeados i coneguts per ser involucrats en la resposta a frio en los cromosomes 2HL, 4HL i 5HL.
Los ensayos en localidades múltiplas de poblaciones de mapeo se utilizan frecuentemente para testar genotipos en un conjunto de ambientes representativos de la condiciones climáticas donde se quieren introducir dichos genotipos. La primera parte de esto trabajo ha sido la evaluación de la población de mapeo ‘Nure x Tremois’ constituida de 118 de doble haploides de cebada, junto con panel de asociación que comprende 185 variedades de cebada representativas del germoplasma cultivado en la cuenca Mediterránea. El material vegetal ha sido ensayado en una combinación de dieciocho campos por año dislocados en seis países de la cuenca mediterránea. Los ensayos se han llevado a cabo en campos con diferente disponibilidad de agua, clasificados en base a los datos relativos a las frecuencia y cantidad de las precipitaciones o en el mismo sitio con un campo en secano y otro regado. Los ensayos se llevaron a cabo por dos años en cada localidad y esto permitió la recogida de un gran volumen de datos que comprenden caracteres agronómicos relacionados con rendimiento y componentes del rendimiento, datos fenológicos y ambientales. Dichos datos se utilizaron después para la identificación de regiones genomicas involucradas en la adaptación de la cebada al ambiente. Los 118 dobles haploides de la población ‘Nure x Tremois’ se genotiparon con marcadores DaRT (Diversity Array Technology), después un set de 15 marcadores CAPS Y SCCP para genes candidatos involucrados en la regulación de las fases fenológicas fueron añadidos al mapa de ligamento construido con los marcadores DaRT. Los datos fueron utilizados para hacer una análisis de QTL con procedimiento ‘Composite Interval Mapping’ para cada combinación ambiente/ carácter. Se encontraron varios QTLs por rendimiento y fecha de espigado y componentes del rendimiento. Los QTL mas frecuentes encontrados por rendimiento y fecha de floración y componentes del rendimiento están localizados en los cromosomas 1H (3 campos), 2H (8 campos) y 5H(5 campos) coincidentes respectivamente con HvFT3 locus, eam6/Eps-­‐2 (earliness per se) locus y con el locus de vernalización Vrn-­‐H1. Una ulterior análisis de QTL hecha con el método “Multi Environment Trial” ha revelado que los QTL localizados en el locus eam6/Eps-­‐2 (cromosoma 2H) y Vrn-­‐H1 (cromosoma 5H) son comunes por rendimiento y fecha de floración en los 18 campos de ensayo. Por esto utilizamos todos lo datos ambientales coleccionadas durante todo el ciclo del cultivo para investigar la sensibilidad de dichos QTL a las co-­‐variables ambientales. La mayoría de las asociaciones encontradas están relacionadas con temperaturas y variables relacionadas con estas. Eam6/Eps-­‐2 muestra una interacción de tipo cuantitativo con dichas variables mientras Vrn-­‐H1 muestra una interacción de tipo cualitativo con dichas variables. Las 185 variedades ensayadas fueron genotipadas con 185 SNPs y fenotipadas por resistencia a frío en dos ensayos uno en España y otro en Italia. El primer ensayo fue caracterizado por un invierno excepcionalmente frío, mientras el de Italia ha sido utilizado en pasado por testar resistencia a frío debido a los inviernos rígidos que suelen registrarse en dicha localidad. Los datos fueron utilizados para llevar a cabo la analisis GWAS “Genome Wide Association Analysis”. Los resultados permitieron identificar 13 regiones genomicas involucradas en la resistencia a frio. Entre ellas tres regiones coinciden con loci ya mapeados y conocidos por ser involucrados en la respuesta a frio en los cromosomas 2HL, 4HL y 5HL.

Field experiments were carried out to determine the effect of nitrogen on the yield, nitrogen uptake and grain nitrogen concentration of spring barley grown for malting. The effects of the rate, timing of application and the form in which the fertiliser nitrogen was applied were studied. The form of fertiliser nitrogen applied had little effect on grain nitrogen concentrations, except under dry soil conditions, when concentrations were higher using calcium nitrate fertiliser. Calcium nitrate also improved grain yields at low fertiliser rates, but at rates nearer recommended levels there was little difference in yield between fertiliser forms. Split or late applications of fertiliser nitrogen only improved yields when applied as calcium nitrate, and then only when early applications had been followed by heavy rain. At low fertiliser rates, the efficiency of recovery of fertiliser nitrogen (¹⁵N) in plant shoots was greater, when applied as calcium nitrate than when applied as ammonium sulphate or ammonium nitrate. Efficiency of recovery fell at higher rates in calcium nitrate treatments, but rose in ammonium sulphate treatments. Under the dry soil conditions in 1989, the efficiency of recovery was significantly increased in all fertiliser treatments. Uptake of fertiliser nitrogen was rapid in the calcium nitrate and ammonium nitrate treatments, usually reaching a maximum by anthesis. There was evidence of losses between anthesis and harvest of fertiliser nitrogen previously taken up by the crop. The uptake of soil nitrogen in the calcium nitrate treatments remained constant over the range of rates and timings of fertiliser application. There was evidence of increasing uptake of soil nitrogen with increased rates of ammonium sulphate fertiliser at several sites, possibly due to 'pool substitution' of ¹⁵N-labelled fertiliser. Uptake of soil nitrogen was less rapid than fertiliser nitrogen before anthesis, but continued right up to harvest in most treatments.

Bibliography: leaves 119-143. The work described in this thesis was designed to investigate one component of the plant's defence against pathogen attack, namely the production of PR-5 proteins... Several roles have been proposed for PR-5 proteins including adaption of plant cells to osmotic stress, antifreeze activity, polysaccharide hydrolase activity, fungal plasma membrane pore forming activity, and a-amylase/trypsin inhibition. The experiments that are described in the thesis were aimed at defining the function of barley PR-5 proteins.(abstract)

The control of pollen viability and release is of major commercial importance in the development of crops for hybrid seed production and selective breeding. It has been shown that key transcription factors in Arabidopsis particularly MALE STERILITY1 (MS1), are functionally conserved in rice (Li et al., 2011), therefore extending this comparative analysis and controlling fertility in temperate cereals, such as barley, is the long term goal of this project. Although anther and pollen development of barley seems morphologically similar to Arabidopsis, the genes involved and how they are regulated are currently unknown. Arabidopsis MS1 is a tapetum specific transcription factor which is expressed exclusively from the tetrad stage to early microspores release. Identification and accurate staging of barley anther development is essential for expression analysis and functional characterisation of genes involved in pollen development. Therefore, a complete morphological study of barley development was conducted. External characteristics have been described in parallel to anther development in order to predict anther stages by the observation of external stages phenotypic traits. Characterization of the barley orthologue of MS1 (HvMS1) has been conducted. Recently a new grass genome has been released, Brachypodium distachyion. This new resource has been used to aid primers design alongside the rice OsPTC1 sequence, the orthologue of MS1 (Li et al., 2011). Genome sequencing has indicated that the Brachypodium genus is more closely related to wheat and barley than it is to rice, Due to the close relationship between Brachypodium and barley, this new grass has been used as intermediary to identify the OsPTC1 orthologue in barley as well as downstream MS1 targets. A highly similar sequence to OsPTC1 was found in Brachypodium, Bradi4g31760. This new gene, as a result of its similarities to OsPTC1, was considered as its putative orthologue gene in Brachypodium. Therefore, the most conserved areas between OsPTC1-Bradi4g31760 were used for primers design to successfully amplify equivalent gene in barley (HvMS1). The characterization of this barley gene showed a similar expression pattern to the MS1 putative orthologue in Arabidopsis of tapetum specific expression. In addition, RNAi silencing of this gene has revealed that it is essential for the normal development of pollen, with a lack of viable pollen produced in the putative HvMS1 silenced transgenic lines.

The storage proteins of barley are both qualitatively and quantitatively important in determining the nutritional quality of the grain and its technological uses. The development of the barley endosperm was followed from anthesis to grain maturity by light and electron microscopy. The deposition of storage proteins in the sub-aleurone and starchy endosperm was studied using conventional electron microscopy. Correlated studies using thick sections of zinc iodide-osmium tetroxide impregnated tissue have illustrated the three-dimensional interrelationships of the endoplasmic reticulum, Golgi apparatus and vacuoles during protein deposition. To provide a clearer understanding of protein deposition in the wild-type barley, protein body formation was also investigated in mutant barley lines where a reduced and modified synthesis of storage protein is associated with an altered protein body structure. Immunocytochemical localization of A, B, and C hordeins and the chymotrypsin inhibitors, CI-1 and CI-2, primary antibodies raised in rabbit and subsequently labelled with protein A-goId illustrated the storage protein in accumulating reserves in protein bodies of the wild-type barley, and the high-lysine mutant lines. Storage proteins were localized only in specific regions of both cytoplasmic and vacuolar protein deposits. A comparison of specimen preparation techniques including different fixation and embedding protocols indicated that for barley endosperm ,tissue post-fixed with osmium tetroxide and embedded in Spurr resin gave superior results to those embedded in LR White or Lowicryl K4M resin. In situ hybridization was used to locate mRNA for CI-1 and CI-2 chymotrypsin inhibitors in barley endosperm using a biotinylated cDNA probe. The probe was localized at an ultra structural level by incubation with avidin-peroxidase and subsequent DAB staining of the peroxidase activity. The combined approach of thin- and thick- sectioning techniques for electron microscopy, in association with the molecular techniques of immunocytochemistry and in situ hybridization, has led to the development of a new model to illustrate the course of protein body development in barley endosperm. This new model also explains those previously published results used to support apparently contradictory earlier schemes.

Standard analysis of malt flour can mask the heterogeneity of hydrolytic enzyme activity. Kernel heterogeneity can lead to brewhouse problems and a product with unpredictable nitrogen and fermentable sugar content. The variability between individual grains of important malting characteristics was measured in malt samples produced under aerobic and anaerobic conditions. Various parameters (including germinative energy, germinative capacity, moisture content, β-glucanase activity, friability and homogeneity) were measured to ensure that the 5 d aerobic Optic malt, produced in Heriot-Watt university micromaltings, was viable and of commercial quality. The 5 d aerobic malt kernels produced at Simpsons Maltings in Berwick-Upon- Tweed were heavier than the micromalt. Commercially produced malt kernels had higher levels of fermentable sugars and soluble nitrogen than the micromalt despite lower α-amylase, β-amylase and ‘total’ limit dextrinase activity. Differences between the 5 d aerobic micromalt and the 5 d aerobic commercially produced malt are indicative of why micromalting cannot always be used as a model system for what is happening industrially and must be modelled on commercial practice. Subjecting 5 d aerobic micromalt to 24 h anaerobic incubation resulted in increased levels of fermentable sugars per l wort. 24 h anoxia also resulted in increased α-amylase and limit dextrinase activities. There are potential industrial applications for this anaerobic wort. Limit dextrinase inhibitor protein present in crude extract prepared from mature barley, eluted from a gel filtration column at a higher molecular weight than expected. The limit dextrinase inhibitor protein either aggregates or binds to other proteins in a high molecular weight complex.

One-irrigation barleys have been selected for performance with a pre-plant irrigation to fill the soil to field capacity to a depth of 5 feet. The barley is then grown with no additional irrigation, which simulates conditions of the North African coast. In this study, two of these barley selections were planted at four planting rates at three dates in Marana to determine optimum seeding rates. A seeding rate of 20 lbs /A resulted in greater yields than 40, 60, or 80 lbs /A when the data were combined for all planting dates.

The yield of crop dry matter is closely dependent upon the amount of solar radiation intercepted by the crop canopy. This in turn is primarily determined by the amount of leaf area and its persistence. This study was concerned with the influence of environments, nitrogen supply and plant density in controlling apical development and leaf growth and development in barley. Three series of experiments were carried out on sequentially sown spring barley (cv. Claret) to cover the whole range of the natural variation in environmental variables. In the first series of experiments there were 4 sowing dates, 4 levels of nitrogen and plants were grown in perlite in small pots. In the second series there were 3 sowing dates, 4 levels of nitrogen and plants were grown in soil and sand compost in small pots. In the third series of experiments there were 3 plant densities, 2 levels of nitrogen and plants were grown in soil and sand compost in large tanks. A strong effect of growth media and size of pot on leaf growth was observed. The plants grown in soil had longer leaves and had more tillers than plants grown in perlite. Leaves were even longer when plants were grown in large tanks. Primordia initiation on the main shoot apex, leaf appearance and leaf extension were best described as linear function of thermal time rather than Julian time. Rate of leaf appearance on the main shoot was found to be linearly related to the rate of change of daylength at crop emergence. Final leaf length depended upon both the rate and duration of leaf extension. However, most of the variation in final leaf length was due mainly to variation in leaf extension rate. Leaf extension rate increased with nitrogen supply. A significant quadratic relationship between leaf extension rate and leaf nitrogen content was observed. It is suggested that irrespective of growing conditions leaf extension rate (in mm °Cd-1 ) is most probably controlled by the nitrogen content in the leaf rather than external nitrogen supply. High temperatures, long days and fast leaf appearance rates all resulted in shorter leaf extension duration. Of these variables variation in temperature accounted for the greatest proportion of variation in leaf extension duration. In general all the plant parameters recorded were affected by nitrogen supply, but the effect was more pronounced in perlite. There was a smaller response to applied nitrogen in soil because of the residual nitrogen supplied by the breakdown of organic matter. Lamina area and dry weight increased with the position of leaf on the main shoot up to 2 leaf insertions before the flag leaf. The flag leaf was always much smaller than the subtending leaves. This ontogenetic drift in leaf size was associated with variations in leaf extension rate and leaf extension duration of the leaves. Final leaf size was affected by plant density. As density increased the size of the first three leaves was increased but the size of upper leaves was dramatically decreased. As density increased, final leaf number and the position of the largest leaf on the main shoot were decreased. Nitrogen affected the position of the largest leaf on the main shoot. As nitrogen supply increased the position of longest leaf moved higher up the main stem. This pattern was also modified by sowing date. In sowings made in June, where rate of crop development was fastest, leaf 4 was the first leaf to show response to nitrogen. In sowings made in September, which developed more slowly, leaf 6 was the first leaf to show response to nitrogen. These effects are attributed to effects of internal competition for nitrogen. This suggests that the size of the later leaves is reduced due to lower availability of nitrogen. Early stem extension will also result in greater competition for nitrogen. On this basis one would expect a large response to nitrogen in fast developing crops and this was the pattern observed in these experiments. For most of the leaf growth parameters recorded in these experiments there were significant sowing date * nitrogen supply * leaf position interactions, which have not been reported in previously published investigations. This indicates the complex way in which these factors control leaf growth.

Bibliography: leaves 131-153. This thesis investigates the mechanisms of manganese (Mn) efficiency (genetic tolerance to Mn-deficient soils) in barley (Hordeum vulgare L.) at both physiological and molecular levels.