Construction of an introgression line population for cultivated peanut (Arachis hypogaea) to facilitate breeding with wild relatives Arachis batizocoi and Arachis stenosperma

Cultivated peanut is susceptible to several highly damaging pests, pathogens and abiotic stressors, largely due to its very narrow genetic base. However, a ploidy barrier exists between cultivated and highly resistant wild peanuts, which makes the process of interspecific hybridization relatively laborious and beyond the scope of many peanut breeding programs. Thus, the peanut breeding community would greatly benefit from a germplasm collection that captures the diversity represented by wild peanut species in a format that is compatible with cultivated peanut and easily introduced into breeding programs. To this end, we report the construction of a structured introgression line (IL) population bearing introgressions from the wild species A. stenosperma and A. batizocoi. The IL population, which has 32 lines in total, has been constructed to maximize genome coverage across the cultivated peanut allotetraploid genome with complementary introgressed segments of a mean size of 34.7 Mbp. Nine of 10 chromosomes in the A subgenome and six of 10 in the B subgenome have at least one introgression. 60.1% of polymorphic markers from A. stenosperma and 34.8% from A. batizocoi are covered by introgressions. The phenotypic diversity of the population is demonstrated through several traits, including disease resistance and plant height. This IL population will be released for public use to the broader peanut research and breeding community. The open-ended nature of this resource will allow researchers and breeders to exploit the genetic value of these two wild peanut relatives for a number of traits without themselves needing to take on the task of interspecific hybridization.