Genetic mapping reveals the complex genetic architecture controlling slow canopy wilting in soybean

Authors: MENKE, ETHAN - University Of Georgia; STEKETEE, CLINTON - University Of Georgia; Song, Qijian; SCHAPAUGH, WILLIAM - Kansas State University; Carter Jr, Thomas; Fallen, Benjamin; ZENGLU, LI - University Of Georgia

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/23/2024
Publication Date: 4/17/2024
Citation: Menke, E., Steketee, C.J., Song, Q., Schapaugh, W.T., Carter Jr, T.E., Fallen, B.D., Zenglu, L. 2024. Genetic mapping reveals the complex genetic architecture controlling slow canopy wilting in soybean. Theoretical and Applied Genetics. 137(5). Article e107. https://doi.org/10.1007/s00122-024-04609-w.
DOI: https://doi.org/10.1007/s00122-024-04609-w

Interpretive Summary: Drought stress is the leading cause of yield loss in soybean. The obvious solution is irrigation, but only 10% of soybean fields are irrigated. A more sustainable option is to develop soybean lines that tolerate drought. Slow or delayed canopy wilting due to drought stress has been observed in a few exotic soybean accessions and may be useful for yield improvement under drought conditions. In this study, 130 different soybean lines derived from drought-resistant exotic soybean accessions were evaluated under drought stress. Over four years, field evaluations were conducted at three locations across the US (Georgia, Kansas, and North Carolina). Substantial variation in canopy wilting observed among the different soybean lines across environments was utilized to identify genetic markers associated with delayed canopy wilting and increased agronomic performance. These genetic markers provide new opportunities to better understand the mechanisms of slow canopy wilting and may be useful for targeted selection and development of new drought tolerant soybean lines.

Technical Abstract: In soybean [Glycine max (L.) Merr.] drought stress is the leading cause of yield loss from abiotic stress in rain-fed U.S. growing areas. With only 10% of the US soybean production under irrigation, plants must possess physiological mechanisms to tolerate drought to combat drought stress. Slow or delayed canopy wilting is a physiological trait that is observed in a few exotic plant introductions (PIs) and may lead to yield improvement under drought stress. In this study, canopy wilting on 130 recombinant inbred lines (RILs) derived from Hutcheson × PI 471938 under drought stress was visually evaluated and RILs were genotyped with the SoySNP6K iSelect BeadChip. Over four years, field evaluations of canopy wilting were conducted under rain-fed conditions at three locations across the US (Georgia, Kansas, and North Carolina). Due to the variation in weather between locations and years, the phenotypic data were collected from seven environments. Substantial variation in canopy wilting was observed among the genotypes in the RIL population across environments. Three QTLs were identified for canopy wilting from the RIL population using composite interval mapping on chromosomes 2, 8, and 9 based on combined environmental analyses. These QTLs inherited the favorable alleles from PI 471938 and accounted for 11, 10, and 14% of phenotypic variation. The QTLs identified through this research can be used as targets for further investigation to understand the mechanisms of slow canopy wilting. These QTLs could be deployed to improve drought tolerance by allowing for the targeted selection of the genomic regions in PI 471938 that provide slow canopy wilting in new soybean cultivars.