Understanding genome structure facilitates the use of wild lentil germplasm for breeding: A case study with shattering loci

Plant breeders are generally reluctant to cross elite crop cultivars with their wild relatives to introgress novel desirable traits due to associated negative traits such as pod shattering. This results in a genetic bottleneck that could be reduced through better understanding of the genomic locations of the gene(s) controlling this trait. We integrated information on parental genomes, pod shattering data from multiple environments, and high‐density genetic linkage maps to identify pod shattering quantitative trait loci (QTLs) in three lentil interspecific recombinant inbred line populations. The broad‐sense heritability on a multi‐environment basis varied from 0.46 (in LR‐70, Lens culinaris × Lens odemensis) to 0.77 (in LR‐68, Lens orientalis × L. culinaris). Genetic linkage maps of the interspecific populations revealed reciprocal translocations of chromosomal segments that differed among the populations, and which were associated with reduced recombination. LR‐68 had a 2–5 translocation, LR‐70 had 1–5, 2–6, and 2–7 translocations, and LR‐86 had a 2–7 translocation in one parent relative to the other. Segregation distortion was also observed for clusters of single nucleotide polymorphisms on multiple chromosomes per population, further affecting introgression. Two major QTL, on chromosomes 4 and 7, were repeatedly detected in the three populations and contain several candidate genes. These findings will be of significant value for lentil breeders to strategically access novel superior alleles while minimizing the genetic impact of pod shattering from wild parents. Core Ideas Two major quantitative trait loci for shattering were repeatedly detected across multiple environments in three lentil populations. Translocations in cultivated relative to wild genomes interfere in recombination and increase linkage drag. Translocations on chromosome 7 in some wild species could be problematic for avoiding one shattering locus. Understanding genomic rearrangements helps breeders plan for successful introgression of wild alleles. Plain Language Summary Lentil breeders can be reluctant to use wild relatives in their programs because it might bring in undesirable traits such as pod shattering. This creates a genetic bottleneck, limiting the diversity available for crop improvement. To overcome this, it is crucial to understand the specific locations of genes controlling these undesirable traits. In our research, we used data from populations derived from crosses betwee