A diallel analysis of eight upland cotton (Gossypium hirsutum L.) genotypes was conducted in the field over two years to determine the potential for improvement in within-boll seed yield components and fiber quality parameters. Four exotic germplasm lines from the converted race stock (CRS) collection and four commercial types representing Texas, mid-South, and Eastern production regions were crossed and evaluated in a diallel with parents but without reciprocals according to Griffing's Model I, Method 2. Significant variation for genotypic, general combining ability (GCA) effects, and specific combining ability (SCA) effects (P 0.05) were identified for all traits studied indicating potential for improvements through selection. Significant interactions of these parameters with years were also observed, suggesting that selection should be based on multiple years and or locations. In addition to effects on yield, individual seed number traits were found to respond to heat stress under controlled growth chamber conditions, suggesting their potential for use in screening genotypes for heat tolerance. These traits were not found to interact with temperature, which indicates that selection for improvements in these traits could be conducted in any environment. Improvements in seed yield components and, putatively, in heat tolerance could be achieved using CRS M-9044-0162. As expected, CRS accessions reduced fiber quality parameters in addition to other agronomic traits, suggesting that improvements for within-boll seed yield components and heat tolerance should be made utilizing a backcross approach. Also observed in this population was a superior hybrid for fiber length and fiber strength from the cross of TAM 94L-25 with PD 6186. This combination could lead to improved fiber length and strength potential in upland cotton.

Anthracnose, caused by <i>Colletotrichum truncatum</i>, is a major disease of lentil (<i>Lens culinaris</i> Medik.) on the Canadian prairies. Resistance to the more virulent race Ct0 of the pathogen is extremely rare within the <i>L. culinaris</i> gene pool thus resistance is being introgressed from <i>Lens ervoides</i>. The overall hypothesis of this project was that resistance derived from <i>Lens ervoides</i> accession L-01-827A would provide uniquely low levels of resistance to <i>Colletotrichum truncatum</i>. Individual studies were performed to: i) test field-resistance of interspecific lines; ii) develop a cutting-method to generate replicated phenotypic data on single plants; iii) study the deterioration of resistance between the juvenile phase (JP) and adult phases (AP) in the line CDC Redberry; and iv) examine genetic control of resistance in a susceptible and partially resistant background. Field evaluations of <i>L. culinaris x L. ervoides</i> lines indicated resistance genes from the wild species will provide unprecedented levels of disease control and heritability of the trait was estimated to be moderate. Single plant phenotyping of resistance is unreliable, thus the feasibility of using clonal propagation of individual plants to generate replicated ratings was evaluated. Results showed consistency in segregation ratios between cutting and seedling-derived plants of the same population, thus the method was utilized for testing of genetic control of segregating populations. CDC Redberry showed varying disease levels depending on the age of the plants with resistance acquisition in the JP that decreased as the plants proceeded through the AP. The F₁, F₂ and F_2:3 generations of two introgression populations were tested for resistance. Resistance from <i>L. ervoides</i> to both races of <i>C. truncatum</i> appeared to be due to the same gene(s) or from the same linkage block in both populations. Models for genetic control were consistent between F₂ and F_2:3 generations, however were different between the populations depending on whether the interspecific line was crossed into a susceptible or partially resistant <i>L. culinaris</i> background. However duplicate recessive epistasis seemed to control susceptibility in the susceptible background and when JP resistance was not a factor. There were significant differences between the JP and AP on more than a third of the F₂s tested supporting different resistance gene action based on growth phase. Resistance in the JP seemed to be due to dominant and recessive epistasis. It was postulated that the the populations may have had segregation distortion commonly found in interspecific populations, thus the previously described genotypes for cotyledon colour and albino plants were used to test the hypothesis of segregation distortion. Segregation of these traits were found to be similarly distorted to previously reported interspecific <i>L. culinaris x L. ervoides</i> populations supporting the hypothesis that continued segregation distortion was found in the introgression populations. Overall, it was found that resistance derived from <i>L. ervoides</i> accession L-01-827A is a highly effective source for the lentil breeding program, however the result suggest more than one backcross to <i>L. culinaris</i> be necessary to properly integrate the resistance genes to eventually obtain fully fertile, adapted lentil cultivars.

The development of cottons with improved fiber quality has been a major objective in breeding programs around the world. Breeders have focused their attention on improving fiber strength and length, and have generally not used fiber elongation in the selection process. Although literature has reported a negative correlation between fiber elongation and tenacity, this correlation is weak and should not prevent breeders from simultaneously improving fiber tenacity and fiber elongation. Furthermore, the work of rupture property, important in the spinning process, could be best enhanced by improving both fiber tenacity and fiber elongation. Fifteen populations were developed in 2007 by crossing good quality breeding lines with high elongation measurements to ‘FM 958’; a High Plains standard cultivar with good fiber quality but reduced elongation. Samples in every generation were ginned on a laboratory saw gin, and the lint was tested on HVI (High Volume Instrument). The F2 and F3 generations showed a wide range of variation for elongation (6.9% - 12.8% for the F2 and 4% - 9.20% for the F3) allowing divergent selection for low and high fiber elongation. A correlation (r) of -0.32 between strength and elongation was observed in the F2 individual plant selections. In the F3, the correlation (r) between strength and elongation was -0.36, and in the F4 the correlation (r) was -0.08. Nine lines were selected from the original 15 populations for spinning tests. The correlation between fiber elongation and strength for these lines was positive (r=0.424), indicating that with targeted selection, fiber elongation and strength can be simultaneously improved. Fiber elongation was positively correlated with yarn tensile properties tenacity (r=0.11), work-to-break (r=0.68) and breaking elongation (r=0.87); and was negatively correlated with yarn evenness properties, number of thin places (r=-0.16), number of thick places (r=-0.9), nep count (r=-0.24), hairiness (r=-0.38) and total number of imperfections (r=-0.38). All selections for high elongation were superior for all tensile properties compared to the low selections and the check in the analysis over locations and in each location. Furthermore, selections for high elongation were significantly different from the selections for low elongation and the check. In addition to developing lines for fiber spinning tests with improved, or differentiated, fiber elongation, this project was amended to evaluate and determine the heritability of fiber elongation. Three different methodologies were used to obtain estimates of heritability; variance components, parent off-spring regression, and realized heritability using F3, F4, and F5 generation. No inbreeding was assumed because there was no family structure in the generations within this study. Estimates of heritability by the variance component methods in the F3, F4 and F5 were 69.5%, 56.75% and 47.9% respectively; indicating that 40-50% of the variation was due to non-genetic effects. Parent off-spring regression estimates of heritability were 66.1% for the F3-4 and 62.8% for the F4-5; indicating a high resemblance from parents to off-spring. Estimates of realized heritability were obtained to determine the progress realized from selection for the low and high selection for fiber elongation. Estimates were intermediate (0.44–0.55), indicating moderately good progress from selection. The results from this project demonstrate that it is possible to improve fiber elongation and to break the negative correlation between elongation and strength. Furthermore, it has been demonstrated that improving fiber elongation results in the increase of length uniformity index and decreased short fiber content. Additionally, directed divergent selection was a successful methodology for the improvement of fiber elongation, and was useful to demonstrate that higher fiber elongation has a positive effect on yarn tensile properties, yarn evenness and processing. The development of new cultivars with improved fiber elongation will improve the quality and reputation of U. S.-grown cotton. The ultimate result will be better yarn quality and improved weaving efficiency, and particularly address current weaknesses in U. S. –grown cotton cultivars, especially from the High Plains of Texas, of more short fiber content, lower uniformity ratios, and weaker yarn strength.

Anthracnose, caused by <i>Colletotrichum truncatum</i>, is a major disease of lentil (<i>Lens culinaris</i> Medik.) on the Canadian prairies. Resistance to the more virulent race Ct0 of the pathogen is extremely rare within the <i>L. culinaris</i> gene pool thus resistance is being introgressed from <i>Lens ervoides</i>. The overall hypothesis of this project was that resistance derived from <i>Lens ervoides</i> accession L-01-827A would provide uniquely low levels of resistance to <i>Colletotrichum truncatum</i>. Individual studies were performed to: i) test field-resistance of interspecific lines; ii) develop a cutting-method to generate replicated phenotypic data on single plants; iii) study the deterioration of resistance between the juvenile phase (JP) and adult phases (AP) in the line CDC Redberry; and iv) examine genetic control of resistance in a susceptible and partially resistant background. Field evaluations of <i>L. culinaris x L. ervoides</i> lines indicated resistance genes from the wild species will provide unprecedented levels of disease control and heritability of the trait was estimated to be moderate. Single plant phenotyping of resistance is unreliable, thus the feasibility of using clonal propagation of individual plants to generate replicated ratings was evaluated. Results showed consistency in segregation ratios between cutting and seedling-derived plants of the same population, thus the method was utilized for testing of genetic control of segregating populations. CDC Redberry showed varying disease levels depending on the age of the plants with resistance acquisition in the JP that decreased as the plants proceeded through the AP. The F₁, F₂ and F_2:3 generations of two introgression populations were tested for resistance. Resistance from <i>L. ervoides</i> to both races of <i>C. truncatum</i> appeared to be due to the same gene(s) or from the same linkage block in both populations. Models for genetic control were consistent between F₂ and F_2:3 generations, however were different between the populations depending on whether the interspecific line was crossed into a susceptible or partially resistant <i>L. culinaris</i> background. However duplicate recessive epistasis seemed to control susceptibility in the susceptible background and when JP resistance was not a factor. There were significant differences between the JP and AP on more than a third of the F₂s tested supporting different resistance gene action based on growth phase. Resistance in the JP seemed to be due to dominant and recessive epistasis. It was postulated that the the populations may have had segregation distortion commonly found in interspecific populations, thus the previously described genotypes for cotyledon colour and albino plants were used to test the hypothesis of segregation distortion. Segregation of these traits were found to be similarly distorted to previously reported interspecific <i>L. culinaris x L. ervoides</i> populations supporting the hypothesis that continued segregation distortion was found in the introgression populations. Overall, it was found that resistance derived from <i>L. ervoides</i> accession L-01-827A is a highly effective source for the lentil breeding program, however the result suggest more than one backcross to <i>L. culinaris</i> be necessary to properly integrate the resistance genes to eventually obtain fully fertile, adapted lentil cultivars.

Crop lands around the world are becoming more salt-affected due to natural processes and agricultural practices. Due to this increase of salinization, acquisition of saline tolerant germplasm for breeding purposes is becoming a priority. Although cultivated sunflower is classified as a moderately salt tolerant crop, highly tolerant germplasm may be of value. The goal of this study was to screen Helianthus spp. in order to determine the salt tolerance of different genotypes. To accomplish this goal, a novel method of rapid screening was developed. Screening for tolerance at initial growth stages was accomplished by germinating seeds in varying concentrations of NaCl solution in petri dishes. Radicle lengths were measured as an indicator of tolerance. This method identified genotypes that are more tolerant than others during germination. Greenhouse trials were also conducted to ascertain morphological measurements during vegetative stages. Two field locations were chosen to screen germplasm for tolerance through physiological maturity; College Station, TX with low salt concentrations and Pecos, TX with high concentrations of salt in the soil and water. Vegetative growth measurements showed a significant genotype by environment interaction. Due to insect infestation in both locations, yields could not be accurately measured and thus compared between sites in 2010. Yields between locations in 2011 showed significant differences and identified germplasm more suited for cropping in salt affected soil. Seed oil content was determined with Fourier Transform Near-Infrared Spectroscopy. Seed oil content was not significantly different between locations, but was highly significant between genotypes. These screenings identified genotypes that are more salt tolerant than others.

<p>In this project relational and Lotus Notes database technology are evaluated with regard to their suitability in providing computer-based support in plant breeding in general and specifically in the production of doubled haploids. The two developed databases are compared based on a set of requirements produced together with the DH-group which is the main users of the databases. The results indicate that both Lotus Notes and the relational databases are able to fulfil all needs documented in this project, although both systems have their limitations. An often expressed opinion is that it is difficult to combine biology and databases. The experience gained in this project however suggests that it does not need to be the case in instances where data is not as complicated as often discussed. Observations made during this project indicate that data warehousing with integrated data mining and OLAP tools are surprisingly similar to how the DH-group at Svalöf Weibull works and could be a suitable solution for the production of doubled haploids.</p>

Thesis (Ph. D.)--University of Missouri-Columbia, 1999. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1999. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

A diallel analysis of eight upland cotton (Gossypium hirsutum L.) genotypes was conducted in the field over two years to determine the potential for improvement in within-boll seed yield components and fiber quality parameters. Four exotic germplasm lines from the converted race stock (CRS) collection and four commercial types representing Texas, mid-South, and Eastern production regions were crossed and evaluated in a diallel with parents but without reciprocals according to Griffing's Model I, Method 2. Significant variation for genotypic, general combining ability (GCA) effects, and specific combining ability (SCA) effects (P 0.05) were identified for all traits studied indicating potential for improvements through selection. Significant interactions of these parameters with years were also observed, suggesting that selection should be based on multiple years and or locations. In addition to effects on yield, individual seed number traits were found to respond to heat stress under controlled growth chamber conditions, suggesting their potential for use in screening genotypes for heat tolerance. These traits were not found to interact with temperature, which indicates that selection for improvements in these traits could be conducted in any environment. Improvements in seed yield components and, putatively, in heat tolerance could be achieved using CRS M-9044-0162. As expected, CRS accessions reduced fiber quality parameters in addition to other agronomic traits, suggesting that improvements for within-boll seed yield components and heat tolerance should be made utilizing a backcross approach. Also observed in this population was a superior hybrid for fiber length and fiber strength from the cross of TAM 94L-25 with PD 6186. This combination could lead to improved fiber length and strength potential in upland cotton.

Laboratory experiments, genetic simulation, and theoretical analyses were performed to address several objectives related to the use of genetic markers in plant breeding programs. Two software packages were developed: GREGOR provides flexible and efficient computer algorithms for performing genetic simulation experiments, and KIN provides improved methods for estimating coancestry from known pedigrees. Random amplified polymorphic DNA (RAPD) markers were investigated in elite barley lines, and estimates of genetic distance based on RAPD markers were compared to estimates based on coancestry. Both types of estimate can provide information that is useful to breeders and geneticists. Genetic simulation was used to investigate the power, accuracy and precision of several methods that are available for analyzing quantitative trait loci (QTL). In most cases, simplified methods of QTL analysis based on linear regression were similar or superior to more complex methods based on mixture models. Methods for genetic analysis using selective genotyping and pooled DNA were also investigated. These methods may allow precise estimates of the positions of markers and QTL to be made.