Screening of Common Bean Genotypes for Moderate and Severe Drought Stress In the Great Plains.

Drought stress reduces common bean (Phaseolus vulgaris L.) yield more than 60% of the worldwide production and is an increasing problem for U.S. production. The purpose of this study was to identify common bean germplasm with tolerance to drought stress and adapted to the Great Plains. Evaluation was perform on 9 commercial cultivars, 16 breeding lines from the UNL-USDA shuttle breeding program, and 10 germplasm accessions from the U.S. and CIAT core collections, for a total of 35 genotypes. Genotypes were screened under moderate drought stress conditions at Carrington, ND and under severe drought stress conditions at Mitchell, NE during 2009. Entries from the core collections were previously selected for photoperiod insensitivity in 2006 and 2007 in Puerto Rico and Nebraska. The effect of drought was tested using adjacent non-stressed (NS) and drought stressed (DS) blocks. A randomized complete block design with four replications in each condition was used, with Beryl-R, Bill Z, Marquis, Orion, Poncho, and SEN 21 as checks. To quantify drought severity, a drought intensity index (DII) was used. At Carrington, drought stress was minimal (DII = 0.07) with 95.8 mm of accumulated precipitation at 65 d after planting. At Mitchell, drought stress was moderate (DII = 0.32) with 77.8 mm of accumulated precipitation at 53 d after planting. Under DS conditions, yield and 100-seed weight were reduced an average of 32 and 13%, respectively, relative to NS conditions. Stampede pinto bean was well adapted to both NS and DS conditions. USPT-CBB-6 and NE25-07-18 had the second and third highest yield under DS (2,703 and 2,633 kg ha¹, respectively). Progress is being made in breeding for the identification of tolerant genotypes for drought stress for the Great Plains. More trials are been conducted in order to confirm results.