Successful Introgression of Abiotic Stress Tolerance from Wild Tepary Bean to Common Bean

Common bean (Phaseolus vulgaris L.) production is limited due to abiotic stresses, including drought and subzero temperatures. Tepary bean (P. acutifolius Gray), a relative of common bean, has been reported to be tolerant to these stresses. Preliminary studies screening wild tepary accessions for cold tolerance demonstrated that W6 15578 is a potential donor of cold tolerance, so an interspecific backcross population derived from a cross between it and common bean (NY5-161) was developed. A 3-yr field study was conducted in Saskatoon, SK, to identify lines able to withstand subzero temperatures better than the common bean parent at the seedling stage. Introgression lines were also tested for response to terminal drought under field conditions in Isabela, PR, over 3 yr. Days to flowering and yield measurements, along with subzero temperature and drought stress tolerance data, are presented. Although the interspecific introgression lines were backcrossed twice to common bean to improve the fertility and increase the proportion of common bean genome, several introgression lines performed better than the common bean parent under both stress conditions. Future breeding objectives include backcrossing to tepary to try to recover additional abiotic stress tolerance genes, as well as using selected introgression lines as breeding material to develop common bean varieties with increased subzero temperature stress and drought stress tolerance. Interspecific introgression of portions of the tepary bean genome into common bean is a promising method for increasing abiotic stress tolerance in common bean.