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).