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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Plant Sci. | doi: 10.3389/fpls.2019.01481

Understanding the Genetic Basis of Spike Fertility to Improve Grain Number, Harvest Index, and Grain Yield in Wheat Under High Temperature Stress Environments

Sumit Pradhan1,  MD A. BABAR1*,  Kelly Robbins2,  Guihua Bai3,  Richard E. Mason4,  Jahangir Khan1, Dipendra Shahi1, Muhsin AVCI1, Jia Guo1, Mohammad M. Hossain1, Madhav Bhatta5,  Mohamed Mergoum6, Senthold Asseng1, Paul St. Amand7,  Salvador A. Gezan1, ByungKee Baik3, Ann Blount1 and Amy Bernardo7
  • 1University of Florida, United States
  • 2Cornell University, United States
  • 3Agricultural Research Service, United States Department of Agriculture, United States
  • 4University of Arkansas, United States
  • 5University of Wisconsin-Madison, United States
  • 6University of Georgia, Griffin Campus, United States
  • 7Kansas State University, United States

Moderate heat stress accompanied by short episodes of extreme heat during the post anthesis stage is common in most US wheat growing areas and causes substantial yield losses. Sink strength (grain number) is a key yield limiting factor in modern wheat varieties. Increasing spike fertility (SF) and improving the partitioning of assimilates can optimize sink strength which is essential to improve wheat yield potential under a hot and humid environment. A genome-wide association study (GWAS) allows identification of novel quantitative trait loci (QTLs) associated with SF and other partitioning traits that can assist in marker assisted breeding. In this study, GWAS was performed on a soft wheat association mapping panel (SWAMP) comprised of 236 elite lines using 27,466 single nucleotide polymorphisms (SNPs). The panel was phenotyped in two heat stress locations over three years. GWAS identified 103 significant marker-trait associations (MTAs) (p ≤ 9.99 x 10-5) related to eight phenotypic traits including SF (a major component of grain number) and spike harvest index (SHI, a major component of grain weight). MTAs detected on chromosomes 1B, 3A, 3B, and 5A were associated with multiple traits and are potentially important targets for selection. More than half of the significant MTAs (60 out of 109) were found in genes encoding different types of proteins related to metabolism, disease, and abiotic stress including heat stress. These MTAs could be potential targets for further validation study and may be used in marker-assisted breeding for improving wheat grain yield under post-anthesis heat stress conditions. This is the first study to identify novel QTLs associated with SF and SHI which represent the major components of grain number and grain weight, respectively, in wheat

Keywords: Single nucleotide polymorphisms, genotyping-by-sequencing, Marker-trait associations, Quantitative Trait Loci, Genome-Wide Association Study, Spike fertility, Spike harvest index, marker-assisted breeding

Received: 30 May 2019; Accepted: 25 Oct 2019.

Copyright: © 2019 Pradhan, BABAR, Robbins, Bai, Mason, Khan, Shahi, AVCI, Guo, Hossain, Bhatta, Mergoum, Asseng, St. Amand, Gezan, Baik, Blount and Bernardo. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Mx. MD A. BABAR, University of Florida, Gainesville, 32611, Florida, United States,