Meta-analysis of QTLs Involved in Pre-harvest Sprouting Tolerance and Dormancy in Bread Wheat

Abstract

In common wheat, meta-analysis of quantitative trait loci (QTL) associated with pre-harvest sprouting tolerance (PHST) and dormancy was carried out using results of 15 studies involving 15 different mapping populations. The study was restricted to only four chromosomes including three chromosomes of homoeologous group 3 (3A, 3B and 3D) and the chromosome 4A, since QTLs for PHST and dormancy on these four chromosomes were reported in several earlier studies, thus making these chromosomes suitable for meta-QTL analysis. The software BioMercator 2.1 was used to build a consensus map, and QTLs were projected on to this map for conducting meta-analysis. Using 36 of the 50 original QTLs, 8 meta-QTLs (MQTLs) were identified: 7 MQTLs were located on chromosomes of homoeologous group 3 including 3A (2 MQTL), 3B (3 MQTL) and 3D (2 MQTL), 1 MQTL was located on chromosome 4A. Confidence intervals (C.I.) for each of these 8 MQTLs were particularly narrow. The mapping information for 50 QTLs was also used for "overview" analysis to visualize important genomic regions carrying the MQTLs for PHST and dormancy. Co-localizations between candidate genes for dormancy/PHST (taVP1 and TaGA20-ox1) and MQTL positions appeared globally significant, although these candidate genes deserve further investigation. Markers associated with 8 MQTLs identified during the present study should prove helpful for introgression of tolerance against pre-harvest sprouting (PHS) into high yielding wheat varieties through marker-assisted selection (MAS).

Effects of TaPHS1 and TaMKK3-A Genes on Wheat Pre-Harvest Sprouting Resistance

“…Gene markers for TaPHS1 and TaMKK3-A have been shown to be useful in MAB, thus they can be applied in breeding to select these two genes to improve PHS resistance. However, in this study, the selected backcrossing progenies with both resistance genes still showed higher average germination rates than their PHS-resistant donors in most experiments (Tables 1 and 3), suggesting that other minor genes in both donor parents might also be important for reducing PHS [33]. Identifying and accumulating natural mutations and the non-grain color related resistance QTLs with TaPHS1 and TaMKK3-A could greatly enhance the PHS resistance in white wheat [3,19].…”

Improving Genomic Prediction for Pre‐Harvest Sprouting Tolerance in Wheat by Weighting Large‐Effect Quantitative Trait Loci

“…Because whitegrained wheat is generally preferred for wheat-based noodles and whole-grain bread products, efforts have been made to develop PHS-tolerant white-grained varieties (Kottearachchi et al, 2006;Liu et al, 2008;Graybosch et al, 2013). Even so, some studies have shown PHS to be affected by many small-effect loci throughout the genome (Tyagi and Gupta, 2012). Marker-assisted selection techniques have shown some promise in this area, with several QTL identified for PHS (Kumar et al, 2010;Liu et al, 2008;Mares et al, 2005).…”

“…For example, a major QTL for PHS tolerance was identified in the hard white wheat cultivar Rio Blanco (Liu et al, 2008), and the underlying gene, designated as TaPHS1, has been cloned and characterized (Liu et al, 2013). Even so, some studies have shown PHS to be affected by many small-effect loci throughout the genome (Tyagi and Gupta, 2012). For this reason, using genomewide markers could be a more effective approach when breeding for tolerance to PHS.…”

Approaches to improve wheat grain quality: breeding for falling number

“…К настоящему времени гены/локусы (QTLs/QPhs), ассоци-ированные с УкПП, идентифицированы и маркированы на всех хромосомах (Крупнов и др., 2010;Tyagi, Gupta, 2012). Большинство из этих локусов являются минорными, они характеризуются весьма малым (менее 10 %) вкладом в изменчивость и сильной зависимостью от внешней среды.…”

“…Большинство из этих локусов являются минорными, они характеризуются весьма малым (менее 10 %) вкладом в изменчивость и сильной зависимостью от внешней среды. Мета-анализ 15 различных популяций, состоящих из рекомбинантных инбредных линий (9), удвоенных удвоенных гаплоидов (5) и беккроссов (1), показал 8 MQPhs, в том числе на хромосомах 3А (2 MQTL), 3В (3 MQTL), 3� (2 MQTL) и 1 MQTL на хромосоме 4A (Tyagi, Gupta, 2012). У озимой белозерной мягкой пшеницы Rio Blanco основной QPhs.pseru-3AS колокализован с пшеничным гомологом M�THER �F FL�WER��NG T��ME-подобным геном (обозначен как TaPHS1), который является крити-ческим регулятором УкПП (Liu et al, 2013).…”