ARS | Publication request: Mapping of quantitative trait loci for canopy wilting trait in soybean (Glycine max L.

Submitted to: Journal of Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 19, 2012
Publication Date: May 8, 2012
Citation: Hussein, A., Carter Jr, T.E., Purcell, L., King, A., Ries, L., Chen, P., Schapaugh, W., Sinclair, T., Boerma, R. 2012. Mapping of quantitative trait loci for canopy wilting trait in soybean (Glycine max L.. Journal of Theoretical and Applied Genetics. 125:837-846.

Interpretive Summary: Most climate models predict greater extremes in weather for food producing areas. Increased drought is a major part of that weather change. Agricultural researchers are just beginning to figure out how to respond to this food challenge. One exciting approach is to build a better soybean that can withstand episodes of drought. This paper is groundbreaking work that provides plant breeders new tools they will need to successfully build the better, more drought tolerant, bean. USDA scientists identified an exotic soybean type from Japan that wilts more slowly under drought stress than normal farmer varieties. A multi-institutional multi-discipline group of researchers has collaborated on a large project to figure what makes the slow wilting Asian soybean tick. The novel report here shows that quite a few genes (seven) control this slow wilting trait. These genes have been tagged and now plant breeders have an efficient method for transferring these genes into farm varieties via applied plant breeding. These results represent a big step forward in fending off the more extreme climate challenges that are likely to ensue. The multi-disciplinary approach used here is a perfect model as to how difficult problems in the climate change area can be dissected and solved.

Technical Abstract: Drought stress adversely affects [Glycine max (L.) Merr] soybean at most developmental stages, which collectively results in yield reduction. Little information is available on relative contribution and chromosomal locations of quantitative trait loci (QTL) conditioning drought tolerance in soybean. A Japanese germplasm accession, PI 416937, was found to possess drought resistance. Under moisture deficit conditions PI 416937 wilted more slowly in the field than elite cultivars and has been used as a parent in breeding programs to improve soybean productivity. A recombinant inbred line (RIL) population was derived from a cross between PI 416937 and Benning, and the population was phenotyped for canopy witling under rain-fed field conditions in five distinct environments to identify the QTL associated with the canopy witling trait. In a combined analysis over environments, seven QTL that explained 75% of the variation in canopy wilting trait were identified on different chromosomes, implying the complexity of this trait. Five QTL inherited their positive alleles from PI 416937. Surprisingly other two QTL inherited their positive alleles from Benning. These putative QTL were co-localized with other QTL previously identified as related to plant abiotic stresses in soybean, suggesting that canopy wilting QTL may be associated with additional morpho-physiological traits in soybean. A QTL on chromosome 12 (Gm12) was detected in the combined analysis as well as in each individual environment, the positive allele at this QTL was inherited from PI 416937 and explained 27% of the variation in canopy wilting. QTL identified in PI 416937 could provide an efficient means to augment field-oriented development of drought tolerant soybean cultivars.