Mapping Domestication Traits in Soybean By Wild Soybean Ril Populations.

Soybean (Glycine max) was domesticated in East Asia 4,000-6,000 years ago from the wild progenitor Glycine soja. The domestication process led to many distinct morphological changes in soybean that adapted it to cultivation, such as upright growth and large seeds. The objective of this research is to map the genes/QTLs that underlie traits differentiating the two species to help understand the genetic basis of soybean domestication. Through genetic dissection of the key domestication-related traits, we also hope to identify targets for introgressing novel alleles or genes into Glycine max which were eliminated by selective sweeps during domestication. To accomplish our objectives, we performed field evaluations of two RIL populations consisting of a total of 800 lines from interspecific crosses between Williams 82 and the wild accessions PI468916 and PI479752. These lines were selected from a total population of over 3,000 lines to represent all combinations of two extreme phenotypes for each pair of traits. The experimental lines were grown in a randomized complete block design in six environments. Eleven traits were evaluated, including days to R1 and R8, height, lodging, stem diameter, leaflet size and shape, pod shattering, and seed weight. QTL mapping was done using approximately 20,000 SNP markers obtained through genotyping-by-sequencing.