|Urrea, Carlos -|
Submitted to: Bean Improvement Cooperative Annual Report
Publication Type: Research Notes
Publication Acceptance Date: April 1, 2009
Publication Date: April 15, 2009
Citation: Urrea, C.A., Porch, T.G. 2009. Phenotypic evaluation of a subset of the Phaseolus vulgaris core collections and the P. acutifolius germplasm collection, and advanced common bean lines for drought tolerance in Nebraska. Bean Improvement Cooperative Annual Report. 52:104-105. Interpretive Summary: Drought stress reduces yield in common bean production worldwide and is becoming increasingly important in the US due to the reduction in water resources and to the increase in water use costs. In order to find new sources of tolerance to drought stress, exotic beans and currently cultivars were evaluated. A total of 277 bean lines, including 128 elite lines and cultivars and 149 exotic lines were screened under drought stress (DS) and non-stress (NS) conditions at Mitchell, NE during 2008. Drought stress was moderate during this study and yield in NS and DS ranged from 735 to 3544 kg ha-1, and from 364 to 2743 kg ha-1, respectively. Under DS conditions, seed yield and seed weight were reduced an average of 32 and 13%, respectively, relative to NS conditions. Several cultivars were found to be superior under drought stress and non-stress conditions, including Stampede, USPT-CBB-6, and NE25-07-18. Yield of the exotic lines was lower than the cultivars under both DS and NS environments indicating that progress has been achieved in breeding for improved adaptation and drought tolerance. The superior cultivars will be incorporated in the breeding program to improve drought tolerance in bean.
Technical Abstract: Drought stress is an important constraint for common bean production worldwide and an increasing constraint in US production. To address this issue, exotic common bean and tepary bean germplasm was evaluated from the NPGS and CIAT collections and from US and international breeding programs for their response to drought stress. A total of 277 entries, including 128 cultivars and elite lines and 149 accessions of Phaseolus vulgaris and P. acutifolius were screened under terminal drought stress (DS) and non-stress (NS) conditions at Mitchell, NE during 2008 using an augmented block design. Drought stress was moderate during this study (Drought intensity index (DII) = 0.32) with significant precipitation occurring at 53 d after planting. Yield under NS and DS ranged from 735 to 3544 kg ha-1, and from 364 to 2743 kg ha-1, respectively. Under DS conditions, yield and 100-seed weight were reduced an average of 32 and 13%, respectively, relative to NS conditions. Stampede was well-adapted to both NS and DS environments and had the lowest percent yeild reduction (PR, 5%), smallest drought susceptiblity index (DSI, 0.2) and the largest geometric mean (GM, 2519). USPT-CBB-6 and NE25-07-18 had the second and third highest yield under DS (2703 and 2633 kg ha-1, respectively). The PR of USPT-CBB-6 and NE25-07-1 was 11 and 12%, respectively, with low DSI (0.3 and 0.4, respectively) and high GM (2554 and 2500, respectively). Yield of the PI accessions (P. vulgaris and acutifolius) was lower than the elite lines under both DS and NS environments indicating that progress is being made in breeding for improved adaptation and drought tolerance. Superior genotypes will be selected and incorporated in the breeding program through an ongoing shuttle breeding project to improve drought tolerance in bean.