Original Research ARTICLE
Validation of candidate gene-based markers and identification of novel loci for thousand-grain weight in spring bread wheat
- 1International Maize and Wheat Improvement Center (Mexico), Mexico
- 2Graduate College (COLPOS), Mexico
Increased thousand-grain weight (TGW) is an important breeding target for indirectly improving grain yield (GY). Fourteen reported candidate genes known to enhance TGW were evaluated in two wheat independent and existing datasets of CIMMYT, the Elite Yield Trial (EYT) from 2015-16 (EYT2015-16) and the Wheat Association Mapping Initiative (WAMI) panel, to study their allele effects on TGW and to verify their suitability for marker-assisted selection. Of these, significant associations were detected for only one gene (TaGs3-D1) in the EYT2015-16 and two genes (TaTGW6, and TaSus1) in WAMI. The reported favorable alleles of TaGs3-D1 and TaTGW6 genes decreased TGW in the datasets. A haplotype-based genome wide association study was implemented to identify the genetic determinants of TGW on a large set of CIMMYT germplasm [4,302 lines comprising five EYTs], which identified 15 haplotype blocks to be significantly associated with TGW. Four of them, identified on chromosomes 4A, 6A and 7A, were associated with TGW in at least three EYTs. The locus on chromosome 6A (Hap-6A-13) had the largest effect on TGW and additionally GY with increases of up to 2.60g and 258 kg/ha, respectively. Discovery of novel TGW loci described in our study expands the opportunities for developing diagnostic markers and for multi-gene pyramiding to derive new allele combinations for enhanced TGW and GY in CIMMYT wheat.
Keywords: Triticum aestivum (bread wheat), Thous grain weight, GBS, Haplotypes, GWAS
Received: 02 Jun 2019;
Accepted: 29 Aug 2019.
Copyright: © 2019 SEHGAL, Mondal, Guzman, Barrios, Franco, Singh and Dreisigacker. 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: Dr. Susanne Dreisigacker, International Maize and Wheat Improvement Center (Mexico), Texcoco, Mexico, firstname.lastname@example.org