ASSESSING IMPACTS OF CROP-WILD INTROGRESSION IN LENTIL USING INTERSPECIFIC LENS SPECIES RECOMBINANT INBRED LINE POPULATIONS
Chen, Li-An 1984-
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Lentil (Lens culinaris Medikus) (Lcu) is one of the earliest domesticated plant species. Lens ervoides (Ler) is a wild species from the tertiary genepool carrying resistance to multiple lentil diseases. Two interspecific Lcu x Ler recombinant inbred lines (RIL) populations, LR-26 and LR-59, had been developed to help introduce disease resistance to lentil. The hybridization broadened the genetic base and impacted many traits beyond just disease resistance. In this study, I assessed the variability of several important agronomic and seed-quality traits. The goals of this thesis project were to 1) determine the phenotypic variation of traits of agronomic and seed quality importance resulting from introgression; 2) assess the level of introgression of Ler genome based on genetic markers; and 3) perform marker-trait association analysis to identify introgression regions underlying the agronomic and seed quality traits observed. Seven agronomic traits and five seed quality traits were assessed in multi-environmental field trials across three years. One population, LR-26, was genotyped using genotyping-by-sequencing and the resulting single nucleotide polymorphisms were used to construct a high-density linkage map. There was a significant genotypic and site-year effect on each trait. A reciprocal translocation involving chromosomes 1 and 5 of Lcu with respect to Ler caused several issues, including marker distortion in the rearranged areas which hinted at a possible selection. Also, heterozygosity that was due to aberrant homoeologous pairing as a result of the translocation and semi-sterility from the presence of the translocation probably made maintenance of population size during RIL development challenging. Chromosomal rearrangements caused marker pseudolinkage and a really large linkage group (LG1) that corresponds to parts of chromosomes 1, 5 and 7. QTL results showed that the quantitative traits were controlled by multiple minor-effect QTLs which could be used to track the introgression of desirable traits. However, there could be challenges when selecting for QTLs underlying these rearrangement regions for introgressions using LR-26. Overall, genome introgression has brought tremendous phenotypic variability and help broaden genetic base of lentil. This study showed the potential and challenges using Ler as a genetic resource for lentil breeding.
DegreeDoctor of Philosophy (Ph.D.)
SupervisorBett, Kirstin E.
CommitteeHucl, Pierre J.; Chibbar, Ravindra N.; Nickerson, Michael; Vandenberg, Albert
Copyright DateAugust 2018
crop wild relative