Project Number: 5442-21220-023-52
Project Type: Specific Cooperative Agreement

Start Date: Jun 01, 2008
End Date: May 31, 2009

Objective:
The goal of this research is to simultaneously pyramid white mold (WM) resistance from Phaseolus species of the primary and secondary gene pools and introgress the highest levels of WM resistance into pinto bean, the largest market class in the USA. The specific objectives are to (1) determine complementation or lack thereof among the WM resistant large-seeded Andean dry bean and among the WM resistant interspecific breeding lines (IBL) derived from Phaseolus species of the secondary gene pool, (2) pyramid complementary and additive WM resistance from across Phaseolus species, (3) introgress the highest levels of pyramided WM resistance into pinto bean cultivars, and (4) Determine the effectiveness of pyramided high levels of WM resistance across environments.

Approach:
Three Andean bean and two IBL derived from P. coccineus will be crossed within the group to test for complementation for WM resistance. The representative WM resistant Andean and Middle American dry and green bean and IBL derived from P. coccineus will be used to develop a broad-based multiple-parent population (C0S0). Selected WM resistant (based on greenhouse data in Colorado and Idaho) S2 families of C0S0 will be inter-mated to develop the first gametic-recurrent selection (GRS) cycle (C1S0). The process will be repeated for the second GRS cycle (C2S0). One GRS will be completed each year. The selected C0S2, C1S2, and C2S2 with the highest WM resistance will be compared to measure gains from selection. Highly WM resistant families from each selection cycle will be crossed with pinto bean cultivars for introgression of the highest levels of WM resistance. Also, breeding lines with pyramided resistance will be tested across greenhouse and field environments through the national Bean White Mold Nursery (BWMN) to determine the stability and usefulness of pyramided resistance for combating WM. Thus, for the first time, WM resistance from across the Phaseolus species will be simultaneously pyramided and introgressed into pinto bean cultivars. This project utilizes the broadest range of genetic diversity for WM resistance and encourages inter-state and inter-disciplinary collaboration. Results and seed of WM resistant breeding lines will be shared with researchers via BWMN, progress reports, publications, web sites, meetings, and field days. White mold resistant breeding lines will be used in genetics and breeding studies and to broaden the genetic base of cultivars and combat WM problems of common bean in the USA.