|TRAPP, JENNIFER - Seneca Foods|
|URREA, CARLOS - University Of Nebraska|
|ZHOU, JIANFENG - Washington State University|
|LAV, KHOT - Washington State University|
|SANKARAN, SINDHU - Washington State University|
|Miklas, Phillip - Phil|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/25/2016
Publication Date: 7/1/2016
Citation: Trapp, J., Urrea, C., Zhou, J., Lav, K., Sankaran, S., Miklas, P.N. 2016. Selective phenotyping traits related to multiple stress and drought response in dry bean. Crop Science. 56:1-13. doi: 10.2135/cropsci2015.05.0281.
Interpretive Summary: Dry edible beans are a critical source of protein and income for small-holder resource-poor farmers in Africa and Latin America, and is an important crop in the U.S for export and national consumption. The farm gate value of dry edible beans in the U.S. averages $750 million annually. Drought occurs worldwide and plagues U.S. dryland bean production in the Midwest and Northern Plains. Our project is tasked with developing dry beans with tolerance to drought using conventional breeding techniques. To expedite breeding more information is needed about the critical traits involved in drought tolerance. This study looked at the relationship of 19 different traits on yield of dry bean under drought. Traits included images captured by remote sensing using unmanned aerial vehicles, canopy temperature, leaf greenness, and pod wall partitioning. We implemented a method of looking at lines in a population at the tails (most and least tolerant) of the distribution for response to drought to facilitate characterization of the traits most important to drought response. This method of extreme phenotyping revealed three traits that were highly correlated with drought response across multiple trials in Washington and Nebraska. Greater partitioning of dry matter between the pod wall and seed, increased greenness measured by remote sensing, and increased biomass production were all related to higher yield under drought. This is the first report of using extreme phenotyping in beans to characterize traits related to drought tolerance. These finding will assist breeders with development of drought tolerant cultivars in the U.S., and contribute to developing cultivars for sustainable bean production in developing countries.
Technical Abstract: Dry bean (Phaseolus vulgaris L.) tolerance to stressful environments is not well understood. Moreover, the increasing population sizes necessary for improving genomic resolution of QTL conditioning stress response has made it difficult for phenotyping to keep pace with high throughput genotyping. Our objectives were to: i) use phenotypic extremes from the ‘Buster’/‘Roza’ (BR) RIL population to facilitate examination of 19 traits for relevance to multiple stress and drought response, and ii) determine the effectiveness for phenotypic extremes to validate existing QTL and identify novel QTL conditioning stress response. The 20 most tolerant and 20 most susceptible lines representing the phenotypic extremes for yield response to multiple stresses and terminal drought, from a population of 140 BR RILs, were examined for a total of 19 drought-stress related traits from across multiple trials. Pod wall ratio (PW), plant biomass (BM) and greenness (NDVI) were most associated with seed yield (SY) under stress followed by phenology traits days to flowering (DF), harvest maturity (HM), and seed fill (DSF). Canopy temperature, SPAD, and nine root traits measured were not clearly associated with stress response in this population. Phenotypic extremes validated QTL previously identified in the whole RIL population conditioning SY, DF, HM, DSF, and seed weight (SW). The QTL PW1.1BR and PW2.1BR, BM1.1BR and BM2.1BR, and NDVI2.1BR co-segregated with the major QTL SY1.1BR and SY2.1BR for seed yield on chromosomes Pv01 and Pv02, respectively. Novel QTL for PW1.2BR and NDVI 1.1BR were discovered on Pv01. Phenotypic extremes helped sort through traits relevant to stress response in the BR RIL population and verified the effect of two major QTL in response to terminal drought.