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Hattan, Andrew Joseph. "Energy utilisation in high yielding dairy cows." Thesis, University of Reading, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288678.
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Bielawski, Marcin. "Efficient and High-Yielding Routes to Diaryliodonium Salts." Licentiate thesis, Stockholm : Department of Organic Chemistry, Stockholm University, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-7969.
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Tollefson, Scott. "High Yielding Short Season Cotton Production in Arizona." College of Agriculture, University of Arizona (Tucson, AZ), 1987. http://hdl.handle.net/10150/204475.
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Errington, Meredith. "Nitrogen, Phosphorus and Potassium Redistribution in High-Yielding cotton." Thesis, The University of Sydney, 2013. http://hdl.handle.net/2123/9489.
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Abstract The redistribution of nutrients from one tissue to another is an important process in cotton plants, supplying bolls with the resources required for growth and development. Cotton growth models generally describe redistribution as a supplementary physiological mechanism to supply developing bolls with nutrients when root uptake is limited or inadequate. Despite its acknowledged importance, redistribution is a poorly-described process. The potential remobilisation and subsequent redistribution of vegetative nutrients has been estimated at between 40 and 70% for Nitrogen (N), and has not been quantified for Phosphorus (P) or Potassium (K). The variability of this process in different parts of the cotton plant and the effect of agronomic and environmental factors on this process has not been quantified. Increasing the understanding of how cotton plants use N, P and K, describing the accumulation of these nutrients in different tissues and assessing how the management of the plants affects their distribution and redistribution will help develop systems to maximise nutrient use efficiency, and to link nutrient inputs with the physiological processes of the plants to which they are applied. From 2007 – 2011, eight field experiments were carried out at three sites in northern NSW, Australia, with three main aims. Firstly, to quantify N, P and K redistribution in high-yielding cotton plants; secondly, to examine the effect of plant phenotype on nutrient redistribution; and thirdly, identify the crop management practices that limit nutrient redistribution. Redistribution was calculated at a single leaf and boll scale, in five node segments up the mainstem of the cotton plant, and at the whole plant scale under various treatments. To quantify the redistribution of N, P and K in whole plants, and to compare it between different crops, a novel method for the calculation of redistribution at a whole plant scale was developed, comparing the daily demand for N, P and K from bolls with the daily uptake of nutrients in the whole plant. This was then used to evaluate six high-yielding crops grown in Narrabri and Moree in north-west NSW, Australia in the 2007 – 08, 2008-09 and 2009-10 cotton seasons. A great deal of variability in the redistribution of N, P and K from vegetative to reproductive plants organs was measured, even between crops of a similar size, yield, and nutrient content. Within whole plants, between 6 and 52% of total plant N was redistributed from vegetative to reproductive tissue, 0 and 18% of plant P and 0 and 39% of plant K, highlighting the wide variety in whole plant measurements. Redistribution was not linked to yield or to the ratio of reproductive to vegetative tissue (R: V) for P or K, but for N there was a positive correlation between the R: V ratio and redistribution. Root uptake, redistribution of nutrients from vegetative to vegetative organs and management or environmental stresses were proposed as factors which may have resulted in the variability of N, P and K redistribution in these crops. To define the maximum potential redistribution, and quantify the contribution of redistribution to a single boll, 15N and Rb were applied directly to mainstem and 1st position leaves, and used as tracers to measure the redistribution of N and K individual leaves. The accumulation of N, P and K in each tissue along a single sympodial branch was also described. The relative contribution of the subtending leaves to the 1st position boll on the corresponding node was calculated, and the transport of N and K from the single leaves to leaves and fruit in removed sites throughout the plant defined. A potential redistribution of 75% of leaf N and 85% of leaf K was calculated. The distribution patterns of remobilised N and K from the mainstem and 1st position leaves were different, and both N and K were transported throughout the whole plant. The relative contribution of the mainstem leaf to the 1st position seed was around 5% of the total N and none of the K, while the 1st position sympodial leaf supplied almost 7% of the seed N and 2% of the K. Contributions to the boll wall, second position leaf and leaves and fruit throughout the canopy were calculated. It was hypothesised that the remainder of the seed N and K was supplied from remote sites or root uptake. Comparisons of the redistribution of N, P and K in different parts of the canopy were made by measuring the 15N, Rb (applied in solution to the soil) and P uptake and distribution from flowering to maturity. Plants were divided into 5 node segments and the N, P and K distribution and redistribution within and between sections described. Significant variation between the plant parts for K and P were measured, with the middle portion of the canopy exporting much more P and K than the top and bottom portions. N redistribution reached the predicted potential in the bottom sections of the canopy, but not the top, indicating that there was more redistribution of vegetative nutrients from lower in the canopy. Root uptake accounted for more of the nutrients in mature bolls at the bottom of the plant than the top. The relationship between nutrient and water supply or shortage and N, P and K redistribution was assessed in experiments providing different rates of N, P and K fertiliser and watering the plants at different soil water deficits. High (200 kg N ha-1) and low (50 kg N ha-1) N rates, and high (60 kg P ha-1 and 160 kg K ha-1) and low (no fertiliser) P and K rates were applied pre-planting, with a side-dressing application of N in the high N treatment. Irrigation treatments were applied by watering the plants at two soil water deficits, “wet” at a 40 mm deficit, and “dry” at a 120 mm deficit. Nutrient stress increased the redistribution of N, P and K from vegetative to reproductive plant parts, and water stress decreased it. Unfortunately the inevitable challenges of field experiments meant that some of the treatments were confounded by rainfall or variability in soil nutrient supply. Through all experiments there were no observed correlations between the ratio of reproductive to vegetative organs, or the harvest index, and the redistribution of N, P or K from leaves and stems, questioning the widely held hypothesis that a high boll load or a large ratio of reproductive to vegetative structures places excessive demands on leaf nutrient resources. Thus high-yielding cotton crops may rely on redistribution to supplement only a small proportion of the boll nutrient requirements, and management stresses, nutrient supply to the roots or excess water supply may have more impact on the redistribution process than the boll load of the crop. The thesis describes the nutrient allocation patterns and demands of high-yielding cotton, and helps to explain the physiological basis for variations in nutrient use efficiency between different crops. This data contributes to the understanding of how high-yielding cotton crops use N, P and K and how this understanding can be used to predict and explain the nutrient requirements of cotton plants.
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Prasad, Rajib. "Identification of high seed yielding and stable fenugreek mutants." Thesis, Lethbridge, Alta. : University of Lethbridge, Dept. of Biological Sciences, c2011, 2011. http://hdl.handle.net/10133/3118.
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Fenugreek (Trigonella foenum-graecum L.) was recently introduced to western Canada as a forage crop. To reach its full potential, high yielding, early maturing fenugreek cultivars that produce good seed yield and quality within 100 frost free days need to be developed. In this study, mutation breeding approach was used on five locally adapted fenugreek genotypes to generate variants showing improved seed yield and yield attributing traits that can be used for cultivar development. Mutant generations of these plants were evaluated in multi-location, multi-year trials, and individual plants were selected for high seed and biomass yield. Seeds from a tetraploid fenugreek line and its diploid parent Tristar were grown under multiple environments to understand effect of environment on seed oil content. In addition, mold resistant fenugreek genotypes were identified by screening a collection of fenugreek accessions against a destructive fungal pathogen Cercospora traversiana.<br>xv, 179 leaves : ill. ; 29 cm
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Charlton, Gemma Louise. "The welfare implications of grazing high yielding diary cows." Thesis, Harper Adams University College, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.542599.
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Halm, Grant Bernard. "Domestic market opportunities for high yielding semi-dwarf wheat varieties." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61963.
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Yang, Hsiao-Hsi. "Effects of rubber particle cavitation on the yielding of high impact polystyrene." Thesis, Cranfield University, 1997. http://dspace.lib.cranfield.ac.uk/handle/1826/11337.
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A pre-damage method was developed to determine whether rubber
particle cavitation is responsible for craze initiation, or vice versa.
Tensile tests were carried out on pre-strained high impact polystyrene
(HIPS) specimens which had been annealed above 100 °C to heal any
crazes formed in the PS matrix during pre-straining. Moderate prestraining
followed by annealing was found to reduce the yield stress of
the HIPS, but not the post-yield flow stress. These observations are
related to cavitation for the rubber particles, which results in a fibrillar
structure within the rubber membranes of a typical "Salami' particle.
The reduction in yield stress provides evidence for primary chain
scission in the rubber phase during yielding: on subsequent loading of
the annealed tensile bar, the rubber particle exhibits a reduced
resistance to cavitation because less energy is required to form a void.
It was found in the follow-up pre-straining tests on HIPS blends
and at different testing temperatures that the critical pre-strain is a
function of rubber content and temperature. Comparable effects are
seen in creep tests. Small levels of pre-straining have little effect if the
specimen is not annealed before reloading. The TEM work also confirms
rubber particle cavitation as a rate-determining step in the deformation
of HIPS and supports the view that cavitation precedes crazing. A
modified cavitation model is proposed to account for the deformation of
a cavitated particle under tension. The predictions of this model agree
with the experiments that the resistance of the particle is weakened by
cavitation and crazes could initiate at the lower tension. The technique
of pre-straining and annealing specimens, before submitting them to
conventional tensile tests, provides valuable insight into the
mechanisms and kinetics of toughening.
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Cooper, Marc Damien. "The behavioural need for lying and feeding in the high yielding dairy cow." Thesis, Open University, 2003. http://oro.open.ac.uk/54158/.
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Experiments were conducted to examine the impact of high milk yields on the behaviour and welfare of dairy cows. A preliminary study determined the social interactions existing within a group of 60 cows from which sub-samples of 20 high and 20 low yielding cows, that were not observed to interact with each other, were identified. These cows were used to examine the behavioural strategies employed by dairy cows coping with increased nutritional demands from milk production. Grazing time significantly increased with milk yield, consequently reducing lying time. A second study measured the appetite of high and low yielding cows for concentrates, using operant conditioning. The high yielding cows demonstrated no greater appetite for concentrates, but post-testing behavioural observations indicated greater appetite for forage, suggesting increased motivation to feed. Subsequent experiments investigated the behavioural effects of lying deprivation on dairy cattle welfare, further examining the feeding-lying conflict. Cows forced to stand had reduced milk yields and demonstrated behavioural signs of fatigue, frustration and stress, which were cumulative. When deprived of lying, a post-deprivation increase in this activity was achieved by reducing feeding time. When deprived of both lying and feeding, a feeding, not lying, post-deprivation increase was observed. However, lying was not reduced to extend feeding time. In conclusion, the motivation to feed was greater in high yielding dairy cows. This resulted in extended grazing and a reduced lying time. Lying can be regarded as an important and highly motivated behaviour and may compromise welfare if reduced. The legitimacy of using individual dairy cows as replicates in the statistical analysis of their behaviour was also investigated. There was no significant difference in the coefficients of variation between cows that were free to interact, and those that were not, for a range of behaviours. Therefore, those cows able to interact did not appear to influence each other's behaviour, supporting the use of individual dairy cows as replicates.
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Law, Ryan Andrew. "Effect of energy and protein on fertility and behaviour in high yielding dairy cows." Thesis, Queen's University Belfast, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.486237.
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A series of studies were conducted to investigate the effects of dietary energy and protein supply on behaviour and fertility in the modem high yielding dairy cow. The results demonstrate few direct dietary treatment effects on reproductive perform'ance. However, dietary strategies which alleviate severe negative energy balance in the early post partum period are beneficial to reproductive performance. A more positive energy balance in early lactation was associated with improved ovarian function, namely; earlier commencement to luteal activity, and improved luteal function (essential for embryonic development). In addition, there was a suggestion that a restricted energy allowance in the pre-calving period. could prove beneficial' to fertility in the post-calving period. Significant associations between average daily energy balance and a number of behavioural activities suggests that monitoring of animal behaviour may be a useful indicator of energy imbalance. In particular, standing ruminating in the two hour period post evening milking was strongly negatively correlated with daily energy balance. The expression of this particular behaviour is likely to be a response to stress (displacement behaviour). Oestrous behaviour appears to be unaffected by dietary protein level. The most influential factor on the expression of oestrus was the size of the sexually active group. Multiple cows cycling together appear to produce more intense oestrous cycles with an increased expression of standing immobile on being mounted. Despite being t~e most accurate oestrous behaviour, standing immobile on being mounted was only expressed in 52% of oestrous cycles, making it less useful in oestrous detection. The importance of secondary be~aviours, such as mounting or attempting to mount another cow has been highlighted. Mounting or attempting to mount another cow had a high rate of expression and, when expressed, a high proportion of animals were in oestrus. This behaviour was identified as being the most reliable sign of oestrus.
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Singh, Satya Ram, University of Western Sydney, of Science Technology and Agriculture Faculty, and School of Horticulture. "Biology of the rice leafroller Cnaphalocrocis (Marasmia) exigua (Butler) (Lepidoptera: Pyralidae: Pauristinae) in Fiji." THESIS_FTA_HOR_SINGH_S.xml, 1997. http://handle.uws.edu.au:8081/1959.7/443.
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The rice leafroller Cnaphalocrocis exigua (Butler) in the only species of the rice leaf folder/roller complex in Fiji. It is one of the major rice pests in the country, its pest status being exacerbrated by the cultivation of high-yielding varieties with minimal pest resistance. Detailed studies on the biology of the moth, in particular on the development, emergence, mating and flight behaviour, effect of adult nutrition on fecundity, egg hatchability and longevity, effect of larval nutrition on larval survival, pupation, pupal weight, pupal eclosion, and fecundity, egg hatchability and longevity of resultant adults, parasitism, and population ecology of C. exigua were carried out in Fiji from 1985 to 1987, and from June to August 1990. This study showed that there are several parasitoids of C. exigua in Fiji, and of those the egg and larval parasitoids Trichogramma sp. and Trathala flavo-orbitalis (Cameron) respectively are significant biotic mortality factors. Their impact as natural suppressors of C. exigua in fields of high yielding rice varieties was, however, inadequate to prevent C. exigua reaching damaging levels. Since C. exigua responds strongly to rice varietal differences, plant nitrogen status, and seasonal factors, is suspected to utilise pheromones during mating, and has numerous biocontrol agents in South East Asia and the Philippines, it appears to be an excellent candidate for an integrated pest management (IPM) program in Fiji. Before IPM strategies can be formulated, however, further investigations on rice varietal resistance, exploitation of exotic parasitoids and pathogens, and detailed studies on the possible presence of sex pheromones need to be conducted.<br>Doctor of Philosophy (PhD)
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Victoria, Melanie Villanueva. "Agricultural Technolongy in Bangladesh: a Study on Non-Farm Labor and Adoption by Gender." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/34262.
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There is growing interest in learning the impacts of agricultural technologies especially in developing economies. Economic analysis may entail assessment of employment and time allocation effects of new technologies. An issue of importance in South Asia is the impacts of technological change on a specific type of occupation: rural non-farm activities. In order to fully understand these effects, the research must integrate gender differences and determine if the results would be similar irrespective of gender.
This paper particularly looks at the effects of HYV adoption on time allocation and labor force participation of men and women in non-farm activities. In estimating the effects of HYV adoption on non-farm labor supply, information on the dependent variable, supply of non-farm labor (or the number of days worked while engaged in non-farm labor), is not available for individuals who do not participate in non-farm labor. Hence sample selection or self-selection of individuals occurs. A feasible approach to the problem of sample selection is the use of Heckman's Two Stage Selection Correction Model. Income functions were estimated for males and females while correcting for the sample selection of non-farm wage earners.
An enhanced understanding of the conceptual links among HYV adoption, non-farm labor supply, and gender issues is achieved by discussing the Farm Household Model. The constrained maximization which is drawn from the Farm Household Model would bring about demand functions and reduced form functions for adoption and labor supply. The reduced-form equations are estimated at the individual level for the following: adoption of HYV technology in rice cultivation, and non-farm labor supply of both adult males and females. Regression results are presented for both Ordinary least squares (OLS) and Tobit estimates.
HYV adoption and non-farm labor supply of men and women are influenced by several factors in Bangladesh. The household characteristics assumed to potentially determine technology adoption and non-farm labor decisions are the following: non-farm wages per month of the males and females, farm size, asset value, ratio of yield per decimal land of high-yielding to traditional variety of rice, HYV yield, local variety yield, and the ratio of variance of yield per decimal land of HYV to traditional or local varieties.
The empirical findings suggest that the decision to adopt HYV technology is determined primarily by farm size, value of total assets of the household, ratio of yield per decimal of land of high-yielding to traditional variety of rice, and the ratio of variance of yield per decimal of land of high-yielding to traditional variety of rice. A larger farm size or land owned in decimal unit increases the non-farm labor supply of females, but not of men. HYV yield is significant and positive, while the local variety yield is significant and negative. This means that higher HYV yields increase the supply of non-farm labor of women, while higher local or traditional yields lower women's supply of non-farm labor.<br>Master of Science
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Piñera, Chavez Francsico Javier. "Identifying traits and developing genetic sources for increased lodging resistance in elite high yielding wheat cultivars." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/34045/.
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Lodging is a persistent phenomenon that reduces grain quality and grain yield of wheat. It is defined as the permanent displacement of the plant/shoots from their vertical position. During the Green revolution, wheat plant height was reduced to avoid lodging and allowed growers to increase nitrogen fertilization. This resulted in a considerable increase of grain yield. After the Green Revolution, plant growth regulators were used to further reduce plant height which continued increasing lodging resistance and grain yield. However, lodging susceptibility has not disappeared completely and as yields increase, there is evidence that growers cannot continue to rely on these strategies, raising the question of how to further improve lodging resistance of wheat. Collaborative studies by physiologists, biologists and engineers generated a deeper understanding of lodging (through stem and anchorage failure mechanisms) and the development of models of the lodging process, together with better crop husbandry or agronomic management strategies. Most of these studies were made on winter wheat under a reduced range of environmental conditions. This thesis attempted to further develop lodging mechanisms and models using spring wheat and a wider range of environmental and agronomic conditions and to investigate the genetic control of lodging-proof traits. Field experiments on spring wheat cultivars were carried out in irrigated conditions in NW Mexico and on a winter wheat Avalon x Cadenza doubled-haploid population in rainfed conditions in the UK. A lodging-proof crop was designed for spring wheat growing in NW Mexico that suggests the need for both increased structural stem biomass and a wider root plate spread (anchorage strength). The model also infers that trade-offs with grain yield will occur, mainly because of overlapping of the development of lodging traits with grain yield formation processes. Rapid selection tools for lodging resistance will play a primary role if lodging resistance is to be improved concurrently with grain yield. Fine mapping and validation of QTLs related to lodging traits identified in this study can be used to develop reliable genetic markers that can accelerate selection for lodging resistance concurrently with improvement of genetic yield potential.
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Kawasaki, Yohei. "Elucidation of High Yielding Soybean Characteristics through Comparison of Biomass Production Dynamics between Japanese and US Cultivars." Kyoto University, 2016. http://hdl.handle.net/2433/215606.
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Kyoto University (京都大学)<br>0048<br>新制・課程博士<br>博士(農学)<br>甲第19780号<br>農博第2176号<br>新制||農||1041(附属図書館)<br>学位論文||H28||N4996(農学部図書室)<br>32816<br>京都大学大学院農学研究科農学専攻<br>(主査)教授 白岩 立彦, 教授 奥本 裕, 教授 稲村 達也<br>学位規則第4条第1項該当
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Aeberhard, Karin Béatrice. "Husbandry, feeding, body measurements, metabolic and endocrine traits, fertility and health status in Swiss high yielding dairy cows /." [S.l.] : [s.n.], 1998. http://www.stub.unibe.ch/html/haupt/datenbanken/diss/bestell.html.
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Gaafar, Khalid. "Effect of fat in comparison to starch in an isoenergetic diet on the metabolism of high yielding dairy cows." Doctoral thesis, Universitätsbibliothek Leipzig, 2004. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-33740.
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The aim of the present study was to investigate, firstly, whether the substitution of dietary starch by rumen-protected fat results in visible changes in the protein metabolism by increasing the urea flux and decreasing of AA levels in blood plasma as indicators for a change of AA oxidation, secondly, whether the fat-fed cows use predominantly long chain FA in the processes of milk fat synthesis or as an energy source in oxidation processes, and thirdly, whether the ratio of glucogenic to lipogenic nutrients could affect the supply of glucose in the metabolism of dairy cows. Two experiments were conducted. In either experiments, about 1.8 kg of starch in the ration of the control group were substituted by about 0.7 kg fat as protected fat (Ca salts of palm, soybean and sunflower oils in addition to protected soybeans) in the ration of the fat group. The first experiment was carried out on 32 multiparous high yielding dairy cows (16 Holstein-Friesian cows in each group) during the first 100 d of lactation. The second experiment was carried out in four periods in a cross-over design. Two cows were used in each period during the 6th to the 10th lactation weeks. The cows were infused intravenously with D-[U-13C6]-Glucose. The substitution of starch by protected fat tended to increase the milk production and milk lactose output and to decrease the microbial protein synthesis in the rumen and plasma glucose level. Also, the levels of ß-HBA and NEFA in plasma, the milk urea content and the total urea-flux were increased (P<0.05). Milk protein content but not yield and plasma levels of insulin, Met, Ser and His decreased (P<0.05) but the branched chain amino acids in plasma increased (P<0.05). The oxidation rate of FA was lower in comparison to other sub`strates. In the second experiment, the enrichment of milk fat and blood CO2 by 13C decreased but the recovery of 13C in milk lactose increased (P<0.065) due to high fat intake. The results indicate that the substitution of starch by protected fat can save glucose in the intermediary metabolism for lactose synthesis in the mammary gland and the cows used fatty acids predominantly for milk fat synthesis and not for oxidation.
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Mercz, Tom Imre. "A study of high lipid yielding microalgae with potential for large-scale production of lipids and polyunsaturated fatty acids." Thesis, Mercz, Tom Imre (1994) A study of high lipid yielding microalgae with potential for large-scale production of lipids and polyunsaturated fatty acids. PhD thesis, Murdoch University, 1994. https://researchrepository.murdoch.edu.au/id/eprint/51717/.
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In this study an enrichment and isolation programme was carried out to select for high temperature (30°C) and high irradiance tolerant microalgae from saline and hypersaline environments, for potential biomass and lipid production in large-scale mass culture. The 75 isolates were dominated by pennate benthic diatoms, motile chlorophytes and cyanophytes. Seventeen diatoms and 4 chlorophytes were screened to determine which isolates had the best growth characteristics, and the highest biomass and cellular lipid content, in both indoor laboratory and outdoor glasshouse conditions.
The most promising of these isolates, the 4 diatoms strains, Amphora coffaeofonnis Ag. M-158, M-160. M-174 and Nitzschia communis Rab. M-169, and 2 prasinophytes, Tetraselmis sp. M-165 and M-168, were cultured in 2L air-lift batch cultures, and their growth, biochemical composition and total fatty acid content monitored in the exponential and stationary growth phases. The effect of nutrient limitation, salinity and temperature, and semi-continuous culture was examined in A. coffaeoformis M-158 and Tetraselmis sp. M-168. The culture yield and maximum productivity (productivity during the exponential growth phase), of biomass, total extractable lipid, and the polyunsaturated fatty acids (PUFAs), 20:4(n-6) and 20:5(n-3), was determined to evaluate potential growth strategies to optimise their production.
In light-saturated batch culture, lipid accumulated in the stationary phase in the diatoms (up to 39.8% ash free dry weight AFDW), whereas in Tetraselmis sp. M-168 the lipid content was maximal (around 35.0% AFDW) during the exponential phase. Lipid yield (75.0 mg.L-!) and maximum productivity (28.8 mg.L_l.d"l) was greatest in Tetraselmis sp. M-168, due to its higher growth rate and biomass yields. High irradiance in the glasshouse stimulated both lipid and carbohydrate accumulation in the diatoms, and carbohydrate in Tetraselmis sp. M-168. High irradiance enhanced lipid productivity in the diatoms, but it reduced lipid culture yield in Tetraselmis sp. M-168. Growth-limiting nitrate concentration in both microalgae, and low phosphate concentration in Tetraselmis sp. M-168 reduced biomass and induced carbohydrate accumulation, at the expense of lipid, resulting in decreased lipid yield and productivity.
Silicate limitation in A. coffaeoformis M-158 induced rapid accumulation of lipid (40% AFDW) which was offset by the marked decline in biomass, resulting in similar lipid productivity during the exponential phase, compared to nutrient sufficient conditions. However, a further reduction in growth rate and biomass productivity under nitrate and silicate-limited semi-continuous culture, decreased the lipid productivity compared to nutrient sufficient conditions.
Polyunsaturated fatty acid (PUFA) and 20:5(n-3) content (% of total fatty acids) was maximal during the exponential phase, correlating with maximum growth rate and degree of unsaturation in both algae. High irradiance enhanced the relative content and production of 20:4(n-6) and 20:5(n-3) in A. coffaeoformis M-158 and N. communis M- 169, correlating with an increased degree of unsaturation, while the production of 20:4(n-6) and 20:5(n-3) decreased in Tetraselmis sp. M-168. mainly due to the decreased biomass production.
The culture yield of 20:5(n-3) was highest in both algae under nutrient sufficient conditions, decreasing 3-4.5 fold under low nutrient conditions, whereas the 20:4(n-6) content in A. coffaeoformis M-158 increased at the expense of 20:5(n-3), under low nitrate and low silicate conditions. A. coffaeoformis M-158 also increased its PUFA content in response to increasing salinity (0.88 to 7.0% NaCl) and lower temperature (20°C), resulting in the maximal cellular content (1.5% of biomass) and culture yield of 20:5(n-3) (2.98 mg.L-1) occurring at 20°C. Increasing salinity generally reduced the 20:4(n-6) and 20:5(n-3) yields in both algae, due to the decreasing biomass yields. In Tetraselmis sp. M-168, increasing salinity stress (3.5 to 15.0% NaCl) and sub-optimal temperature, reduced the PUFA content, resulting in the maximal cellular 20:4(n-6) and 20:5(n-3) content (0.75 and 0.34% of biomass, respectively) and yield of 20:4(n-6) and 20:5(n-3) (0.16 mg.L-1 and 0.74 rng.L'1, respectively) coinciding with growth conditions favouring maximum growth rate.
The results indicate that maximum productivity of lipid and 20:5(n-3) can be achieved by optimising growth conditions (nitrate and phosphate, temperature, salinity, irradiance) for maximum growth rate and biomass production. Tetraselmis sp. M-168 is the best candidate for lipid and 20:5(n-3) production in large-scale mass culture due to its high biomass production, and maximal PUFA content coinciding with maximal lipid content during the exponential growth phase. A. coffaeoformis M-158 is the best candidate for 20:4(n-6) production. The physiological significance of changes in the lipid and fatty acid composition in response to environmental factors, and the culture strategy for optimising total lipid and 20:4(n-6) and 20:5(n-3) production in batch and continuous culture are discussed.
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Trautwein, Julia [Verfasser]. "Lucerne silage for high yielding dairy cows : evaluation of the nutritional value using chemical and in vivo methods / Julia Trautwein." Bonn : Universitäts- und Landesbibliothek Bonn, 2018. http://d-nb.info/1152383809/34.
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Taylor, Victoria Jane. "The growth hormone (GH) and insuling-like growth factor (IGF) axis in relation to fertility in the high yielding dairy cow." Thesis, Royal Veterinary College (University of London), 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246921.
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Singh, Satya Ram. "Biology of the rice leafroller Cnaphalocrocis (Marasmia) exigua (Butler) (Lepidoptera: Pyralidae: Pauristinae) in Fiji." Thesis, Richmond, N.S.W. : School of Horticulture, Faculty of Science, Technology and Agriculture, University of Western Sydney, Hawkesbury, 1997. http://handle.uws.edu.au:8081/1959.7/443.
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The rice leafroller Cnaphalocrocis exigua (Butler) in the only species of the rice leaf folder/roller complex in Fiji. It is one of the major rice pests in the country, its pest status being exacerbrated by the cultivation of high-yielding varieties with minimal pest resistance. Detailed studies on the biology of the moth, in particular on the development, emergence, mating and flight behaviour, effect of adult nutrition on fecundity, egg hatchability and longevity, effect of larval nutrition on larval survival, pupation, pupal weight, pupal eclosion, and fecundity, egg hatchability and longevity of resultant adults, parasitism, and population ecology of C. exigua were carried out in Fiji from 1985 to 1987, and from June to August 1990. This study showed that there are several parasitoids of C. exigua in Fiji, and of those the egg and larval parasitoids Trichogramma sp. and Trathala flavo-orbitalis (Cameron) respectively are significant biotic mortality factors. Their impact as natural suppressors of C. exigua in fields of high yielding rice varieties was, however, inadequate to prevent C. exigua reaching damaging levels. Since C. exigua responds strongly to rice varietal differences, plant nitrogen status, and seasonal factors, is suspected to utilise pheromones during mating, and has numerous biocontrol agents in South East Asia and the Philippines, it appears to be an excellent candidate for an integrated pest management (IPM) program in Fiji. Before IPM strategies can be formulated, however, further investigations on rice varietal resistance, exploitation of exotic parasitoids and pathogens, and detailed studies on the possible presence of sex pheromones need to be conducted.
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Winkler, Anne [Verfasser]. "Effects of grape pomace and a polyphenolic plant product during the transition period of high-yielding dairy cows : kumulative Dissertation / Anne Winkler." Halle, 2018. http://d-nb.info/1166140717/34.
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Cantu, Robert. "Synthesis and Characterization of Triphenylene-BODIPY Paddle Wheel Conjugates for Ultra-Fast Light Induced Charge Separation Yielding High-Energy Charge-Separated States." Thesis, University of North Texas, 2019. https://digital.library.unt.edu/ark:/67531/metadc1505171/.
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In the development of covalent organic frameworks (COFs), often the scaffold linkers are assumed to be electro- and photoinactive, and this was also to be the case for 2,3,6,7,10,11-hexahydroxytriphenylene, a tritopic linker. However, as demonstrated in the present study, the reaction product of this linker, hexaoxatriphenylene, is electron rich and when connected to a suitable photosensitizer engages itself in an efficient excited-state charge separation process. In the present study, we have employed BF2-chelated dipyrromethenes (BODIPYs) as sensitizers, which are connected to hexaoxatriphenylene through the center boron, rendering paddle-wheel-type structures. Systematic photophysical, electrochemical, computational, and photochemical studies involving pump-probe femtosecond transient spectroscopy have been performed to establish efficient charge separation in these novel supramolecular structures.
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Niozas, Georgios [Verfasser], Martin [Akademischer Betreuer] Kaske, and Georgios [Akademischer Betreuer] Tsousis. "Extended lactation in high yielding cows : effects on fertility parameters, milk yield, udder health und body measurements / Georgios Niozas ; Martin Kaske, Georgios Tsousis." Hannover : Stiftung Tierärztliche Hochschule Hannover, 2019. http://d-nb.info/1202272193/34.
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Windhausen, Sandra Vanessa [Verfasser], and Albrecht E. [Akademischer Betreuer] Melchinger. "Strategies for selecting high-yielding and broadly adapted maize hybrids for the target environment in Eastern and Southern Africa / Sandra Vanessa Windhausen. Betreuer: Albrecht E. Melchinger." Hohenheim : Kommunikations-, Informations- und Medienzentrum der Universität Hohenheim, 2012. http://d-nb.info/1029506701/34.
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POZZA, LUCA. "Ductility and behaviour factor of wood structural systems - Theoretical and experimental development of a high ductility wood-concrete shearwall system." Doctoral thesis, Università degli studi di Padova, 2013. http://hdl.handle.net/11577/3422988.
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This dissertation focuses on the seismic behavior, ductility and dissipative capacity of modern timber buildings. A number of innovations in the field of timber structures are reported with special regard to the modeling techniques suitable for timber joints and to the characterization of the seismic behavior of modern timber systems.
A preliminary overview on the seismic-resistant timber building technology and on their evolution from the past to nowadays is reported in the introduction of this thesis work. A review of the state of art about the available seismic codes is also reported and the main lack and incongruence with the current constructive practice are pointed out.
The basic terms and concepts used in structural modeling and nonlinear analysis of timber structure are provided in the first part of this dissertation. The specific behavior of wood joints under cyclic actions and therefore under earthquakes is described with emphasis to the pinching effect and strength and stiffness degrading. A literature review on the main numerical models proposed to reproduce the hysteretic load-slip curve of single fasteners, joints and whole wooden elements is presented and discussed. A proposal for a new wood joint numerical model that can be easily implemented into a standard commercial Finite Element code is reported. The reliability of such new developed model to reproduce the fasteners hysteresis behavior is presented and critically discussed in comparison with experimental results.
The second part of this thesis work is based on the evidence that the growing spread of the use of timber structures has led to the development of numerous innovative construction systems but at the same time a lack of code provisions for seismic timber structure still remains, in particular concerning the ductility (or behavior) factor q to be used for the design of different timber systems. This part of dissertation analyzes the definitions of the q-factor given in the scientific literature and its relevance in the design of seismic resistant structures. The traditional methods for estimating the q-factor are investigated and an innovative procedure for expeditious q-factor estimation is presented. The theoretical aspects of this new analytical-experimental procedure are reported and the main advantages and limitations are critically discussed.
The seismic behavior of the Cross Laminated Timber structure is in deep studied in the third part of this dissertation. Such building system is largely spreading in the constructive practice but no design guidelines are provided in the seismic codes yet, especially for what concerning the definition of their sound behavior factor. Aim of this part of dissertation is to define the influence of some significant building characteristics, such as building technology, storeys number, slenderness, design criteria etc.., on the q-factor value. Such influences were studied referring to a numbers of building configuration and by means of nonlinear analyses carried out using specific hysteretic spring lamp-mass models. Based on such numerical assessment a proposal for an analytical formulation suitable to calculate the q-factor of CrossLam buildings has been developed and is presented. The validation and the applicability limits of the proposed formulation are presented and critically discussed.
The final part of the dissertation investigates from the structural efficacy of newly developed construction technology which uses an external concrete shelter made of precast R.C. slabs to improve the performance of standard platform-frame shear walls. The idea consists of external plating made of thin reinforced concrete slabs screwed to the wooden frame of the walls. The concrete slab acts as a diaphragm against the horizontal forces. The structural response of this shearwalls under monotonic and cyclic loading conditions has been assessed by means of experimental tests. The tests outcomes are presented and compared with those from code provisions. Fulfillment of the requirements given by current codes as regards the attribution to the Higher Ductility Class is also verified. The influence of concrete skin on the seismic response of the shearwalls is also evaluated by means of numerical analysis and the assured “q” ductility factor is estimated.<br>In questo lavoro di tesi si analizzano il comportamento sismico, la duttilità e la capacità dissipativa dei moderni edifici con struttura di legno. Le principali innovazioni sviluppate in questa tesi di dottorato riguardano le tecniche di modellazione dei sistemi di connessione usati nelle strutture lignee e la caratterizzazione sismica dei moderni edifici in legno.
L’introduzione della tesi evidenzia le caratteristiche che rendono le strutture in legno idonee per l’impiego in zona sismica e riporta una analisi storica delle principali tipologie di edifici sismo-resistenti a struttura in legno e la loro evoluzione dal passato ai giorni nostri. L’introduzione riporta inoltre un’analisi critica dello stato normativo Europeo ed Extraeuropeo sulle progettazione sismica degli edifici a struttura in legno evidenziando le principali lacune e incongruenze con la pratica costruttiva corrente.
Il lavoro di tesi sviluppato affronta sostanzialmente quattro argomenti dettagliati in parti indipendenti. Le prime due sono di carattere generale e riguardano tutte le strutture in legno mentre le rimanenti sono specifiche di sistemi costruttivi innovativi e non ancora completamente caratterizzati sismicamente.
La prima parte della tesi è dedicata alla descrizione del comportamento isteretico che caratterizza le connessioni utilizzate nelle strutture in legno e dei modelli numerici disponibili in letteratura per una riproduzione fedele di tale comportamento evidenziandone le potenzialità, i limiti di applicazione e l’efficienza numerica. Viene inoltre proposto un modello isteretico innovativo per riprodurre il comportamento delle connessioni tipicamente utilizzate nelle strutture in legno riproducibile anche mediante codici agli elementi finiti di tipo commerciale e non specificatamente orientati alla ricerca. Questa prima parte della tesi si conclude con la validazione e la descrizione dei principali vantaggi e limiti di applicazione della modello numerico proposto.
La seconda parte della tesi riguarda la definizione del fattore di struttura q dei sistemi costruttivi in legno innovati e di recente diffusione che non sono annoverati nelle normative sismiche. In questa parte della tesi vengono descritti i metodi tradizionali utilizzati per la stima del fattore di struttura evidenziandone i vantaggi e i principali limiti. Viene proposta una procedura innovativa di tipo misto analitico-sperimentale che consente una valutazione speditiva del valore del fattore di comportamento q.. Questa parte del lavoro di tesi si conclude riportando la validazione della procedura proposta nonché gli aspetti teorici i limiti di applicabilità.
La terza parte della tesi approfondisse lo studio sul sistema costruttivo a parete massiccia del tipo CrossLam. Preliminarmente viene riportatolo lo stato dell’arte sull’attività di ricerca sinora svolta su tale sistema costruttivo. L’obiettivo di questa parte del lavoro di tesi consiste nella definizione dell’effetto di determinate caratteristiche dell’edificio come il numero di piani, la snellezza, la composizione delle pareti, i criteri di progetto ecc. sul valore del fattore di struttura da utilizzare nella progettazione sismica dell’edificio stesso. Tale correlazione viene studiata mediante una serie di simulazioni numeriche su diverse configurazioni di edifici. I risultati ottenuti sono stati sintetizzati in una nuova formulazione analitica per la definizione del fattore di struttura q a partire dalle specifiche caratteristiche dell’edificio. Infine si riporta la validazione di tale formulazione analitica e si descrivono i principali vantaggi e limitazioni.
L’ultima parte di questo lavoro di tesi consiste nello sviluppo teorico e sperimentale di un nuovo sistema costruttivo misto legno-calcestruzzo ad alta duttilità e performance anti-sismiche. Il sistema sviluppato consiste nell’applicazione di un rivestimento esterno in lastre di calcestruzzo alle tradizionali pareti di taglio a telaio. La riposta strutturale, la duttilità e il comportamento isteretico è stato verificato mediante dei test sperimentali condotti su differenti configurazioni di pareti. Infine sono state condotte delle simulazioni numeriche, con modelli numerici appositamente sviluppati e tarati sulla base dei test sperimentali, mediane le quali è stato possibile stimare il valore del fattore di struttura q da utilizzare per il progetto sismico di questo nuovo sistema costruttivo.
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Лозовий, С. В. "Сучасний стан та особливості формування культур Сосни звичайної ДП «Чернігіврайагролісгосп»". Thesis, Чернігів, 2021. http://ir.stu.cn.ua/123456789/25068.
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Лозовий, С. В. Сучасний стан та особливості формування культур Сосни звичайної ДП «Чернігіврайагролісгосп» : випускна кваліфікаційна робота : 205 "Лісове господарство" / С. В. Лозовий ; керівник роботи М. М. Селінний ; НУ "Чернігівська політехніка", кафедра аграрних технологій та лісового господарства. – Чернігів, 2021. – 91 с.<br>У випускній кваліфікаційній роботі на тему «Сучасний стан та особливості формування популяції сосни звичайної ДП Чернігіврайагролісгосп» здійснено спробу відслідковування існуючої проблематики лісовідновлення з виокремленням найголовнішого аспекту, пов”язаного з процесом природного поновлення на суцільних лісосіках, адже за рахунок його відбувається скорочення періоду лісовирощування на 10-15 років, що потребує значно менших зусиль і витрат коштів, є більш продуктивними та екологічно стійкішими.
Автором доведено, що формування культури Сосни звичайної впливає на природно-кліматичні та ґрунтові умови через стан та інтенсивність росту, їх ценотичну конкурентоспроможність, ґрунтові властивості, формування лісових ценозів і довговічність стану.
Автором обгрунтовано широту екологічної амплітуди Сосни звичайної, якій притаманна пластична коренева система, що залежить від багатьох чинників – типів ґрунтів, їх вологості, складу насаджень, їхньої повноти.
Доведено, що на ділянках із заляганням кам'янистих порід на глибині 20 см і ближче до поверхні ґрунту відбувається масове всихання екземплярів сосни звичайної. Навпаки, із збільшенням глибини залягання кам'янистих порід до 60 см, рослини не зазнають негативного впливу.
Автором проаналізовано досліджуване питання на основі - 100 літературних джерел. В ході дослідження автором було обґрунтовано необхідність певної кількості посадкового матеріалу та розраховано витрати на створення культур на відповідних ділянках господарства.<br>In the final qualifying work of оn the topic "Current state and features of the formation of the population of Scots pine Chernihivrayagrolisgosp" an attempt was made to track the existing problems of reforestation with highlighting the most important aspect related to the process of natural regeneration in continuous felling, because it reduces the period of 10-15 years which requires much less effort and money, are more productive and environmentally sustainable.
The author proves that the formation of Scots pine culture affects the natural, climatic and soil conditions through the state and intensity of growth, their coenotic competitiveness, soil properties, formation of forest cenoses and longevity of the state.
The author substantiates the breadth of the ecological amplitude of Scots pine, which is characterized by a plastic root system that depends on many factors - soil types, their humidity, plant composition, their completeness. It is proved that in areas with stony rocks at a depth of 20 cm and closer to the soil surface there is a mass drying of specimens of Scots pine. On the contrary, with increasing the depth of rocks to 60 cm, the plants are not adversely affected.
The author analyzed the research question on the basis of - 100 literature sources. During the study, the author substantiated the need for a certain amount of planting material and calculated the cost of creating crops in the relevant areas of the farm.
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Salvagiotti, Fernando. "Nitrogen fixation in high yielding soybean (Glycine max., L. Merr)." 2008. http://proquest.umi.com/pqdweb?did=1564016371&sid=1&Fmt=2&clientId=14215&RQT=309&VName=PQD.
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Thesis (Ph.D.)--University of Nebraska-Lincoln, 2008.<br>Title from title screen (site viewed Nov. 25, 2008). PDF text: xiv, 198 p. : ill. ; 4 Mb. UMI publication number: AAT 3315056. Includes bibliographical references. Also available in microfilm and microfiche formats.
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Wheelhouse, Richard T., and D.-F. Shi. "Novel, High-yielding Synthesis of meso-Substituted Porphyrins via the Direct Arylation of Porphine." 2002. http://hdl.handle.net/10454/3620.
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No<br>A new method for the synthesis of meso-substituted porphyrins is described: reaction of 5,10,15,20-tetrabromoporphine magnesium complex with aryl or heteroaryl boronic acids in the presence of Pd(PPh3)4 gave meso-substituted porphyrins in yields up to 70%.
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Pandey, I. Priyanka. "Explicit and implicit contracts in North Indian villages : effects of technology on incentive design /." 1999. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:9934105.
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Shwe, Tin Maung. "Introduction of high yielding rice varieties : implications for the hired agricultural labour market in Burma." 1990. http://hdl.handle.net/1993/17296.
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Yang, Chen-Feng, and 楊振峰. "Study on Influence of Machined Characteristics of Micro-hole EDM Parameters for High-yielding Steel." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/3s43ft.
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碩士<br>崑山科技大學<br>機械工程研究所<br>96<br>Micro-hole electrical discharge machining（Micro-hole EDM）has advantageous characteristics of machining for micro-components and difficult cutting materials with high hardness and high strength. However, because the effect of rapidly heating and fast cooling during the period of machining, the defects, such as micro-cracks, gas holes…etc., was easy to be induced serious influences for machined surface quality.
In this study, the high yielding steel（HY-80） was employed to proceeding micro-hole electrical discharge machining and the material removal rate （MRR）,electrode removal ratio（ERR）, hole-enlargement（HE）, surface morphology were investigated. And the relationship between machining parameters and machining characteristics was studied.
Based on the results of experimental analysis, the pulse current and duration on time increase the MRR and HE will increase. The SEM was used to observe the change of surface topography for high yielding steel of inlet region, middle region, and outlet region after EDM. And when the pulse current was increased, the deeper and bigger EDM craters were found and the height of EDM crater was decreased. The duration on time was increased, the area of EDM crater was increased and the height of crater and pockmark were decreased. Observing the surface crack, we found the less of pulse current, the fewer of the crack. And the pulse current was increased, the number of crack was getting fewer.
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Kalappa, H. K. "Studies on the isolation and evolution of High Yielding multivoltine races of silkworm bombyx mori L." Thesis, 1996. http://hdl.handle.net/2009/1926.
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LIN, CHIA-YI, and 林佳怡. "An Empirical Study on the Relationship between the High and Low Yielding Currencies Exchange Rate Volatility." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/g9g6dw.
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Changaya, Albert Gideon. "Development of high yielding pigeonpea (Cajanus cajan) germplasm with resistance to Fusarium wilt (Fusarium udum) in Malawi." Thesis, 2007. http://hdl.handle.net/10413/968.
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Mushi, Clemence Sebastian. "The role of plant densities and growing degree days in the evaluation of high yielding corn (Zea mays L.) genotypes." 1986. http://hdl.handle.net/2097/22121.
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Gaafar, Khalid Mahmoud Mohamed [Verfasser]. "Effect of fat in comparison to starch in an isoenergetic diet on the metabolism of high yielding dairy cows / presented by Khalid Gaafar." 2004. http://d-nb.info/976051133/34.
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Mucavele, Custodio Estevao. "The economics of smallholder rice producers in Bilene-Macia District, southern Mozambique." Diss., 2001. http://hdl.handle.net/2263/29117.
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Research carried out in several countries has concluded that high yielding varieties (HYV) of rice have tremendous potential compared to traditional rice varieties in alleviating poverty. On the other hand, it is argued that despite increase in yields, high yielding varieties do not benefit the poor farmers because of high costs associated with input acquisition and other operational costs. To further understand the issues related to production and economics of HYV, this study was carried out with its primary objective to assess the profitability of smallholder rice production in Mangol, Bilene district in southern Mozambique. Out of a total population of eighty farmers, sixty farmers participated in this research. Two groups of farmers, one using traditional rice varieties and the other using high yielding varieties were surveyed. The study consisted of field observations; yield measurements and interviews of the farmers using a semi-structured questionnaire. Gross margins were calculated for both traditional input users (TIU) and modem input users (MIU). Results show that an average farmer using high yielding varieties produces 4.4 tons of rice per ha, corresponding to a gross margin of 4 238 000,00 MZM. The highest yield obtained with high yielding varieties was 7.3 tons of rice per ha, producing a gross margin of 10 038 000,00 MZM. On the other hand, an average TIU farmer produces 2.5 tons per ha, realising a gross margin of 3 483 125, 00 MZM. The maximum yield attainable using traditional inputs is 2.9 tons per ha, producing a gross margin of 4 283 125, 00 MZM. The results also show that the lowest yield obtained by farmers using modern inputs was 3.1 tons per ha, producing gross margins of 1 638 000,00 MZM while the lowest attainable when using traditional inputs is 1.7 tons producing gross margins of 1 913 125,00 MZM. The main conclusion of this study was that HYV are more profitable than traditional varieties, both in financial terms, to individual farmer and in economic terms, to the society as a whole. However, due to high production costs, farmers producing HYV must attain yield levels not less than 3.4 tons per ha as yields below that level make little financial incentives and does not motivate farmers to shift from traditional varieties to modern varieties. In order to ensure high yields, farmers must be assisted to carefully implement the recommended agronomic practices because the adoption of high yielding varieties does not ensure profitable yields if the other agronomic and management practices are not observed during the production process. The study also assessed the contribution of agricultural support services such as input supply, credit and extension, on the adoption of new technologies and it was concluded that when agricultural support services are available, farmers can successfully adopt recommended technologies.<br>Dissertation (M Inst Agrar (Agricultural Economics))--University of Pretoria, 2006.<br>Agricultural Economics, Extension and Rural Development<br>unrestricted
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Platen, Matthias [Verfasser]. "Physiologie und Management der Beziehungen zwischen Fruchtbarkeit und Milchproduktion bei Hochleistungskühen = Physiologie and managment of the relations between milk performance and fertility in high-yielding dairy cows / von Matthias Platen." 1997. http://d-nb.info/986135801/34.
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Moloto, Kholofelo Caroline. "Evaluation of F3 segregation cowpea (Vigna unguiculata) population developed from insect-mediated crosses." Thesis, 2019. http://hdl.handle.net/10386/2948.
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Thesis (M.Sc. Agriculture (Agronomy) -- University of Limpopo, 2019<br>Erratic rainfall and insect infestation are some of the factors that limit cowpea production in Limpopo (Asiwe, 2009). Improved cowpea varieties available for dryland production in Limpopo do not meet the farmer’s needs. Specific trait crosses are needed to be made with adapted varieties for the purpose of developing high yielding, pest tolerant and adapted varieties. Varieties with desired specific traits were planted in isolation plots for outcrossing by insects. F1 lines derived from parental lines that were half sib seeds were harvested and planted as F2, and seeds obtained from F2 generation were used to develop F3 segregating population at University of Limpopo Experiential Farm, Syferkuil, and planted along with parents. This F3 generation forms the current evaluation on which this report is based. Data collected included; aphid severity (measured on a 9-point scale), number of days to 90 % maturity, grain yield, 100 seed weight and number of genotypes selected for advancement. Results showed significant variation among progeny over parents therefore expressing transgressive segregation. Genotypes derived from pedigree TX08-30-5 were five while pedigree IT98K-205-8 and IT97K-499-35 had four genotypes each that expressed early maturity (80-90 days) which are desirable for evading drought. Twenty-three genotypes from pedigree GEC and three from pedigree IT97K-499-35 obtained grain yield (>101 g/plot and >161 g/plot) that was better than their parents. Only one genotype derived from pedigree TX08-30-1 expressed high resistance to aphids better than the parent with a mean aphid score range of 1-2. Four genotypes from pedigree TX08-30-5 obtained bigger 100 seed weight (>18.6 g) compared to parent. These progeny also proved to be high yielders as they expressed heterosis for all yield attributes than their parents. Eighty-two genotypes were selected for advancement. Significant variations were observed among progeny giving opportunity to make selections. In most cases, genotypes outperformed their parents which indicate positive heterosis. The 82 promising genotypes selected will be advanced for further selections from multi location testing for stability and adaptation.
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Boyd, Jamie Alice. "The effect of supplementing high yielding Holstein cows with botanical extracts, bacterial inoculants, or dietary glycerol during heat stress and the effect of dietary glycerol in transition cow diets on subsequent yield and efficiency." 2009. http://purl.galileo.usg.edu/uga%5Fetd/boyd%5Fjamie%5Fa%5F200908%5Fphd.
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