ASSESSING IMPACTS OF CROP-WILD INTROGRESSION IN LENTIL USING INTERSPECIFIC LENS SPECIES RECOMBINANT INBRED LINE POPULATIONS
Date
2018-09-05
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
Type
Thesis
Degree Level
Doctoral
Abstract
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.
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Keywords
lentil, pre-breeding, crop-wild introgression, crop wild relative
Citation
Degree
Doctor of Philosophy (Ph.D.)
Department
Plant Sciences
Program
Plant Sciences