Maize (Zea mays L.) inbred lines for hybrid breeding are usually developed within distinct heterotic groups. Breeders impose strong selection and maintain relatively small population sizes that are adapted to local environments, where the aim is to identify the desired recombinant types in the progeny. However, linkages between loci that control a trait may not permit breeders to obtain the desirable genetic recombination in these populations. It is hypothesized that different favorable and unfavorable alleles accumulate within the lines from different heterotic groups. In addition, within each inbred line, favourable alleles are linked with unfavourable alleles. Two early-season maize inbreds, CG60 (Iodent) and CG102 (Stiff Stalk), were used to develop a selfed recombinant inbred line (SRIL) and an intermated recombinant inbred line (IRIL) populations. Furthermore, individuals from within these populations were testcrossed with an inbred tester from the Lancaster Sure Crop heterotic group, to give rise to selfed SRIL testcross (SRIL-TC) and IRIL testcross (IRIL-TC) populations. The inbred and inbred-testcross populations were evaluated for trait variation and QTL mapping. The genetic variance was high in inbred populations (SRIL and IRIL) with transgressive segregation for flowering time and agronomic traits. However, genetic variances and correlation coefficients did not significantly differ between the inbred populations. Results suggested that pleiotropic genes were prevalent for these traits. In addition, linkages between the loci that control these traits were not common within parental genomes. Genetic linkage maps developed from the IRIL population were larger than those of the SRIL population. In the inbred-testcross populations (SRIL-TC and IRIL-TC) high means and high levels of trait variation were observed for all traits. The genetic variances and correlation coefficients of hybrid traits did not significantly differ between the SRIL-TC and IRIL-TC populations. Twenty five significant small to moderate QTL were detected, but only one, for grain moisture, was shared between inbred-testcross populations. Overall, the two inbred parents from different heterotic groups have many distinct alleles that contribute to traits. The recombinant inbred line populations had high means and variances for grain yield and related traits, which opens the possibility of utilizing these lines for hybrid breeding.

The main goal of soybean breeding is to increase yield with improved seed quality characters. The objectives of this thesis were: i) to identify yield quantitative trait loci (QTL) across different mega-environments (ME); ii) to evaluate the relationship between yield and yield components and the co-localization of QTL; iii) to analyze environmental factors that affect QTL expression and identify different ME. Two Canadian x Chinese soybean populations were tested across Canada, northern United States and China. Yield QTL were identified at one, two and three hypothetical ME. Most of them were co-localized with agronomic trait QTL. These results give strong evidence that Canada, northern United States and China are different ME. Novel alleles from plant introductions can favorably contribute directly or indirectly to seed yield and the use of QTL would facilitate their introgression into breeding populations in both North America and China. / National Science and Engineering Research Council of Canada (NSERC) and the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA)

I examined the influence of cyclic feeding regime on fillet yield and quality and their genetic architecture in rainbow trout (Oncorhynchus mykiss). Two lots of half-sib families produced in September and December were exposed to periods of reduced ration followed by increased ration. Fish fed cyclically reduced rations weighed less and had smaller fillets and body proportions relative to controls. They also had less estimated muscle and visceral lipid but also more proportional visceral mass. Lots and families within lots differed significantly for the majority of traits. Genotypic analysis with 23 microsatellite markers spanning 19 linkage groups detected QTL for all traits over multiple linkage groups that were not necessarily consistent between feeding regime and parental lot. Linkage groups RT-9 and 29 had the largest QTL effects for fillet composition traits and overall body size across the greatest number of parents sampled.

Soybean [Glycine max (L.) Merr.] seed is a major source of edible oil in the world and the main renewable raw material for biodiesel production in North America. Oil, which on average accounts for 20% of the soybean seed weight, is a complex quantitative trait controlled by many genes with mostly minor effects and influenced by environmental conditions. Because of its quantitative nature, the seed oil concentration may have an indirect effect on other economically important and agronomic traits such as seed yield and protein concentration. Increasing the oil concentration in soybean has been given more attention in recent years due to increasing demand for both edible oil and feedstock. To achieve this objective, it is important to understand the genetic control of the oil accumulation and its relationship with other traits. The main objectives of this thesis were to identify quantitative trait loci (QTL) and genes involved in oil biosynthesis in soybean. Two recombinant inbred line (RIL) populations were developed from crosses between moderately high oil soybean cultivars with high seed yield and protein concentration. In a population of 203 F3:6 RILs from a cross of ‘OAC Wallace’ and ‘OAC Glencoe’, a total of 11 genomic regions located on nine different chromosomes were identified as associated with oil concentration using multiple QTL mapping (MQM) and single-factor ANOVA. Among the 11 oil-associated QTL, four QTL were also validated in a population of 211 F3:5 RILs from a cross of ‘RCAT Angora’ and ‘OAC Wallace’. There were six oil QTL identified in this study that were co-localized with seed protein QTL and four for seed yield QTL. The oil-beneficial allele of the QTL tagged by marker Sat_020, on Chromosome 9, was positively associated with seed protein concentration. The oil-enhancing alleles at markers Satt001 and GmDGAT2B were positively correlated with seed yield. In this study, three sequence mutations were also discovered in either the coding or non-coding regions of three DGAT soybean genes (GmDGAT2B, GmDGAT2C, and GmDGAT1B) between ‘OAC Wallace’ and ‘OAC Glencoe’ that showed significant effects on some of the traits evaluated. GmDGAT2B showed significant association with seed oil and yield across different environments. The oil-favorable allele of the gene GmDGAT2B from ‘OAC Glencoe’ was also positively correlated with seed yield. GmDGAT2C was associated with seed yield, whereas GmDGAT1B showed significant effects on seed yield and protein concentration. However, neither of these two genes showed any association with seed oil. The yield-enhancing allele of GmDGAT1B showed negative association with protein concentration. The identification of oil QTL that were either positively associated with seed yield and protein or neutral to both traits and the development of new gene-based markers will facilitate marker-assisted breeding to develop high oil soybean cultivars with high yield and minimal effect on protein concentration. / Generous funding to conduct this research was provided by the Alternative Renewable Fuels II Program of the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) and by the Grain Farmers of Ontario.

Young adults who self-injure may prefer to disclose these experiences to peers versus professionals, however, past research has demonstrated that their responses are rated as less helpful compared to other recipients. To better understand this phenomenon, the current study sought to investigate NSSI disclosures from the point of view of the disclosure recipient. Given the relation between various interpersonal trait variables (e.g., receptiveness, responsiveness, agreeableness), relationship factors (friendship quality, duration), and intimate self-disclosures, aspects of particular individuals and relationships may also play a role in the context of peer-to-peer NSSI disclosures and how effective these disclosure responses may be. An online battery of questionnaires was administered to examine these research questions in a population of 230 university students (178 females, M age = 18.38). 107 participants reported receiving a NSSI disclosure from a friend. Having a history of NSSI, lower social support, and greater perceived relative power were found to significantly predict receiving a NSSI disclosure from a friend and receptiveness and social support were found to significantly predict the recipients’ degree of helpful responding to the NSSI disclosure. Findings illuminate the important role of friends and of the friendship itself in facilitating the help-seeking process and promoting NSSI cessation. Research directions and implications are discussed.

Thèse diffusée initialement dans le cadre d'un projet pilote des Presses de l'Université de Montréal/Centre d'édition numérique UdeM (1997-2008) avec l'autorisation de l'auteur.

Scores from high-stakes tests such as the Scholastic Aptitude Test (SAT) are commonly used as criteria for college admission decisions. So, it is of implied importance to identify factors that contribute to susceptibility to failure on these tests. One potential factor addressed in the current study was whether emotional cognitive load differentially impacts those with low working memory capacity or trait anxiety. Individual differences in subjective arousal were also tested as a mechanism contributing to this effect. In Experiment 1, a reading comprehension task revealed that type of cognitive load affected accuracy. In Experiment 2, state anxiety was induced using methods from previous research. The results revealed that, again, only type of cognitive load affected comprehension accuracy. Together, results suggest that arousal induced via disturbing words negatively influence reading performance regardless of superior working memory capacity. These findings are not based on cognitive load in general, but the semantic value of the words processed, in particular, that led to comprehension difficulty. Results are discussed in terms of theoretical and practical implications.

This study offers a brief review of the literature on resilience. The review served as a basis for designing a qualitative study to observe how resilience develops in survivors of breast cancer. Survivors are those who lead productive, satisfying and/or inspirational lives, after their treatment has ended. By using qualitative data collection methods and post hoc data analysis, a purposive sampling of 11 women, in the Midwest, resilient survivors of breast cancer were studied. These women were asked to write brief autobiographies, detailing the important factors and contexts that were evidence of the development of resilience in themselves. Tape recorded interviews allowed participants to add to or delete from their autobiographies.The findings showed the eleven participants shared six common characteristics: (1) making a spiritual connection; (2) having meaningful work; (3) engaging in social activism; (4) being a self-directed learner; (5) living a healthy lifestyle; and (6) expressing a wide range of feelings. In addition, the taped interviews revealed the importance of creativity and authentic relationships. A resilience wheel illustrates the definition of resilience, i.e., as a positive attitude about one's body, mind, spirit and emotions, manifested by living a healthy lifestyle; engaging in meaningful work; forming and maintaining authentic relationships; and-expressing a wide range of feelings appropriately. The study demonstrated resilience is more than effective coping. It is observed and characterized by others as a zest for life.Among these participants, resilience/zest for life was found to have developed in their youth, when they identified with a positive role model/s, who modeled resilient attitudes/values. As children they internalized these values, acting on them in small ways, until adulthood when a life event triggered a shift. As adults they, then, claimed these internalized values as "my own philosophy."Although there was not sufficient evidence to discuss resilience as a developmental process in adulthood, the ages of the participants (40-77) imply the process of learning and growing continues throughout the life span.Suggestions for teaching resilience are offered along with recommendations for future research. / Department of Educational Leadership

The present study attempted to replicate a previously documented typology of perfectionism in a sample of college students (N=216). Furthermore, this study sought to determine whether a set of predictor variables comprised of selected subscales from the Patterns of Adaptive Learning Scales (PALS) and the College Adjustment Scales (CAS) could be used to reliably predict groups of perfectionists. Students' scores from the Frost Multidimensional Perfectionism Scale (MPS) were entered into a two-step cluster analysis, which revealed four clusters: Mixed-Maladaptive (N=62), Pervasive (N=43), Mixed-Adaptive (N=53), and Non-Perfectionists (N=32). A standard discriminant analysis was then calculated, with measures of achievement goal orientation and psychological symptomatology serving as the independent variables, and perfectionism cluster group serving as the dependent variable. This analysis yielded two statistically significant discriminant functions. The first function, labeled Maladaptive Parental Influences, was comprised of two subscales which were related to students' perceptions of their relations with their parents. Pervasive perfectionists showed the highest mean value on the first function, while Non-Perfectionists were lowest. The second function, Intrapersonal Adaptive Outcomes, consisted of a total of seven subscales, four of which measured problem areas for the student, and showed a positive correlation with the overall function value. The other three subscales assessed traditionally adaptive-oriented concepts. Moreover, higher scores on these adaptive-oriented subscales showed a negative correlation with the overall function value, suggesting a lower function value reflected a healthier profile for the individual. As such, Mixed-Adaptive perfectionists showed the lowest mean value on the second function, while Mixed-Maladaptive perfectionists had the highest value. Of particular note, the Performance-Avoid subscale from the PALS was not found to significantly discriminate among the four perfectionism clusters, a surprising result given the conceptual similarities that the two constructs share with one another. However, an interesting new avenue in the study of the development of perfectionism is offered in the current study, whereby students' perceptions of their parents' achievement goals for them were empirically linked to their own manifestations of perfectionism, which had not been previously documented in the literature to the researcher's knowledge. / Department of Educational Psychology

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