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ARS Home » Plains Area » Lubbock, Texas » Cropping Systems Research Laboratory » Plant Stress and Germplasm Development Research » Research » Publications at this Location » Publication #332358

Research Project: Genetic Enhancement of Sorghum as a Versatile Crop

Location: Plant Stress and Germplasm Development Research

Title: Genome-wide association study of heat tolerance of developing leaves during vegetative growth stages in a sorghum association panel

Author
item Chen, Junping
item Chopra, Ratan
item Hayes, Chad
item MORRIS, GEOFFREY - Kansas State University
item SANDEEP, MARLA - Kansas State University
item Burke, John
item Xin, Zhanguo
item Burow, Gloria

Submitted to: The Plant Genome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/28/2016
Publication Date: 3/27/2017
Citation: Chen, J., Chopra, R., Hayes, C.M., Morris, G., Sandeep, M., Burke, J.J., Xin, Z., Burow, G.B. 2017. Genome-wide association study of heat tolerance of developing leaves during vegetative growth stages in a sorghum association panel. The Plant Genome. 10(2):1-15.

Interpretive Summary: Global warming and conspicuous temperature elevation, including the occurrence of frequent and long duration of heat waves are great challenges for agricultural production . The need to understand how natural variation in important crop species can be mined for heat tolerance is more than ever necessary. Here, we analyzed phenotypic variation for responses heat stress in a sorghum association panel- elite group (SAP-elite) representing major races and working groups to identify polymorphisms (SNPs) that are associated with resilience to extended heat waves in the field. Differential response of leaf tissues in terms of heat tolerance were evaluated for 3 years in experiment fields at three locations where sporadic heat waves occur throughout the sorghum growing season. A total of nine SNPs that were significantly associated with leaf firing and five SNPs that were associated with leaf blotching. These SNPs accounted for 65% and 59% of phenotypic variations, respectively. Candidate genes underlying the SNPs were analyzed, with the majority of genes directly linked to biological pathways involved in plant stress responses and specifically to heat stress response. The findings of this research provide new knowledge on the genetic control of heat tolerance in sorghum and can be applied towards elucidation of the genetic and molecular mechanisms underlying heat tolerance in grasses. The results also provide much needed information for the identification of molecular markers for marker assisted breeding (MAS) of heat tolerance in breeding programs.

Technical Abstract: Heat stress reduces grain yield and quality worldwide. Enhancing heat tolerance of crops is one of the essential strategies required for sustaining agricultural production, especially as frequent temperature extremes escalates due to climate change. Although heat tolerance mechanisms have been studied extensively in model plant species, little is known about the genetic control underlying heat stress responses of crop plants under field conditions. In this study, we performed a genome-wide association study (GWAS) for heat tolerance in a sorghum (Sorghum bicolor L. Moench) association panel. Natural variation for heat tolerance of leaf tissues were evaluated for 3 years in experiment fields at three locations where sporadic heat waves occur throughout the sorghum growing season. We identified nine SNPs that were significantly associated with leaf firing and five SNPs that were associated with leaf blotching. These SNPs accounted for 65% and 59% of phenotypic variations, respectively. Candidate genes underlying the SNPs were mined. Many of them are directly linked to biological pathways involved in plant stress responses including heat stress response. The findings of this study provide new knowledge on the genetic control of heat tolerance in sorghum and for the elucidation of the genetic and molecular mechanisms underlying heat tolerance in crops. The results also provide much needed information for the identification of molecular markers for marker assisted breeding (MAS) of heat tolerance in breeding programs.