Project Number: 5348-21000-028-03
Project Type: Specific Cooperative Agreement

Start Date: Sep 16, 2011
End Date: Dec 31, 2013

Objective:
To screen the USDA Core Collection of common bean (Phaseolus vulgaris L.) for resistance to halo blight (Pseudomonas syringae pv. phaseolicola) for US bean improvement.

Approach:
The USDA-NPGS bean core collection will be screened in the greenhouse for resistance to halo blight. We will use race 6 and race 2, the two most predominant races of the pathogen in U.S. in the screening experiment. Priority will be given to those accessions reported as insensitive to photoperiod by Urrea and Porch (2010) which is a set of 300 accessions approximately. If none of the accessions in this subset is resistant, then the rest of the core collection will be evaluated. The core will be initially screened using race 6 isolates of halo blight collected from ND which have been shown to be highly virulent on dry beans. We will use the seedling screening method specified by the Bean Improvement Cooperative (http://www.css.msu.edu/bic/PDF/Halo_Blight.pdf) for resistance evaluation. Basically, seedlings with fully expanded primary leaves will be inoculated and rated on a 1-5 rating scale after disease development. At least two plants and two leaves per plant will be evaluated and experiment be repeated a minimum of two times. Accessions showing high resistance to race 6 will be screened again with a mixture of race 2 and 6 to confirm results and check the reaction to the second race detected in the state.