Genetic dissection of heat-responsive physiological traits to improve adaptation and increase yield potential in soft winter wheat

Authors: PRADHAN, SUMIT - University Of Florida; BABAR, MD ALI - University Of Florida; Bai, Guihua; KHAN, JAHANGIR - University Of Florida; SHAHI, DIPENDRA - University Of Florida; AVCI, MUHSIN - University Of Florida; GUO, JIA - University Of Florida; MCBREEN, JORDAN - University Of Florida; ASSENG, SENTHOLD - University Of Florida; GEZAN, SALVADOR - University Of Florida; Baik, Byung-Kee; BLOUNT, ANN - North Florida Research & Education Center; HARRISON, STEPHEN - LSU Agcenter

Submitted to: BMC Genomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/5/2020
Publication Date: 4/20/2020
Citation: Pradhan, Sumit, Babar, M., Bai, G., Khan, J., Shahi, D., Avci, M., Guo, J., McBreen, J., Asseng, S., Gezan, S., Baik, B.V., Blount, A., Harrison, S. 2019. Genetic dissection of heat-responsive physiological traits to improve adaptation and increase yield potential in soft winter wheat. BMC Genomics. 66:941–950. https://doi.org/10.1007/s10722-019-00742-4.
DOI: https://doi.org/10.1186/s12864-020-6717-7

Interpretive Summary: High temperature (HT) has detrimental impacts on wheat productivity. Climate change will increase the frequency of heat waves in the future. We conducted genome-wide association study (GWAS) on 236 elite soft wheat lines using the three years of phenotypic data in two locations under heat stress. Ten markers associated with multiple physiological traits (pleiotropy) were detected on chromosomes 1D, 2B, 3A, 3B, 6A, 7B, and 7D and five markers that were significantly associated with physiological traits had pleiotropic effects on grain yield and other yield-related traits. Seventy-five markers showed consistent associations with yield traits in multiple environments and more than half of them were found in the genes encoding different types of proteins associated with heat stress. These markers showed consistent associations across environments and with multiple physiological and agronomic traits can be used in marker-assisted selection to develop high yield cultivars with enhanced heat tolerance.

Technical Abstract: Changes in weather pattern including high temperature (HT) due to climate change have detrimental impact on wheat productivity and modeling studies have predicted even more frequent heat waves in the future. Wheat growth can be impaired by high daytime and nighttime temperature at any developmental stage, especially during the grain filling stage. While improving traits like spike fertility ensures optimized partitioning to grain, improving physiological traits has proven successful in past for crop adaptation to HT due to increasing photosynthetic capacity and efficiency. Leaf chlorophyll content, leaf greenness, cell membrane thermostability, and canopy temperature have been proposed as the candidate traits to improve yield potential in wheat under HT. Nonetheless, a significant gap exists in knowledge of genetic background associated with these physiological traits and identifying new genetic loci associated with these traits can facilitate physiological breeding for increased heat tolerance in new wheat cultivars. We conducted genome-wide association study (GWAS) on 236 elite soft wheat association mapping panel using 27,466 high quality single nucleotide polymorphism markers. The panel was phenotyped for three years in two locations where heat shock was present. GWAS identified ~500 significant marker-trait associations (MTAs) (p = 9.99 x 10-4). Ten markers associated with multiple traits (pleiotropy) were detected on chromosomes 1D, 2B, 3A, 3B, 6A, 7B, and 7D which can be potentially important targets for selection. Notably, five MTAs associated with physiological traits had pleiotropic effect with GY and other yield-related traits. Seventy-five MTAs were consistently expressed in multiple environments indicating stability and more than half of these stable MTAs were found in genes encoding different types of proteins associated with heat stress. A large number of MTAs were identified in soft winter wheat under HT. We found several stable loci across environments and pleiotropic markers controlling physiological and agronomic traits. Upon further validation, these MTAs can be used in marker-assisted selection and breeding to develop varieties with high stability for grain yield and enhanced heat tolerance.