|Charlson, Dirk - UNIV OF ARKANSAS|
|Bhatnagar, Sandeep - MONSANTO|
|King, C - UNIV OF ARKANSAS|
|Sneller, Clay - UNIV OF ARKANSAS|
|Purcell, Larry - UNIV OF ARKANSAS|
Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 9, 2009
Publication Date: May 27, 2009
Citation: Charlson, D.V., Bhatnagar, S., King, C.A., Ray, J.D., Sneller, C.H., Carter Jr, T.E., Purcell, L.C. 2009. Polygenic Inheritance of Canopy Wilting in Soybean [Glycine max (L.) Merr.]. Theoretical and Applied Genetics. 119: 587-594. Interpretive Summary: As water demand for agriculture exceeds water availability, cropping systems need to become more efficient in water usage. One way to accomplish this is to deploy cultivars that sustain yield under drought conditions. Soybean cultivars differ in how quickly they wilt during water-deficit stress, and this trait may lead to yield improvement during drought. Four places in the soybean DNA were identified as being associated with leaf wilting. This new information may lead to the development of soybean varieties that use water more efficiently or yield more during drought conditions.
Technical Abstract: As water demand for agriculture exceeds water availability, cropping systems need to become more efficient in water usage, such as deployment of cultivars that sustain yield under drought conditions. Soybean cultivars differ in how quickly they wilt during water-deficit stress, and this trait may lead to yield improvement during drought. The objective of this study was to determine the genetic mechanism of canopy wilting in soybean using a mapping population of recombinant inbred lines (RILs) derived from a cross between KS4895 and Jackson. Wilting was rated in three environments (Arkansas 2000 and 2003, and North Carolina 2002) using a rating scale of 0 (no wilting) to 100 (severe wilting and plant death). Transgressive segregation was observed for the RIL population with the parents expressing intermediate wilting scores. Using multiple-loci analysis, four quantitative trait loci (QTLs) on molecular linkage groups (MLGs) A2, B2, D2, and F were detected (P=0.05), which accounted for 47% of the phenotypic variation of genotypic means over all three environments. An analysis of the data by state revealed that 44% of the observed phenotypic variation in the Arkansas environments could be accounted for by these markers. Only the QTL on MLG F was detected using the North Carolina data where it accounted for 16% of the variation. These results demonstrate that the genetic mechanism controlling canopy wilting was polygenic in nature and provide a foundation for future research to examine the importance of canopy wilting in drought tolerance of soybean.