Mapping QTL for spike fertility and related traits in two doubled haploid wheat (Triticum aestivum L.) populations

Background In breeding programs, the selection of cultivars with the highest yield potential consisted in the selection of the yield per se, which resulted in cultivars with higher grains per spike (GN) and occasionally increased grain weight (GW) (main numerical components of the yield). In this study, quantitative trait loci (QTL) for GW, GN and spike fertility traits related to GN determination were mapped using two doubled haploid (DH) populations (Baguette Premium 11 x BioINTA 2002 and Baguette 19 x BioINTA 2002). Results In total 305 QTL were identified for 14 traits, out of which 12 QTL were identified in more than three environments and explained more than 10% of the phenotypic variation in at least one environment. Eight hotspot regions were detected on chromosomes 1A, 2B, 3A, 5A, 5B, 7A and 7B in which at least two major and stable QTL sheared confidence intervals. QTL on two of these regions (R5A.1 and R5A.2) have previously been described, but the other six regions are novel. Conclusions Based on the pleiotropic analysis within a robust physiological model we conclude that two hotspot genomic regions (R5A.1 and R5A.2) together with the QGW.perg-6B are of high relevance to be used in marker assisted selection in order to improve the spike yield potential. All the QTL identified for the spike related traits are the first step to search for their candidate genes, which will allow their better manipulation in the future.

Automated summary

In this study, QTL for grain weight (GW), grains per spike (GN), and related spike fertility traits were mapped using two DH populations. A total of 305 QTL were identified for 14 traits, with 12 QTL identified in multiple environments explaining over 10% of phenotypic variation in at least one environment. Eight hotspot regions were detected across chromosomes 1A, 2B, 3A, 5A, 5B, 7A, and 7B, highlighting the potential for marker assisted selection to improve spike yield potential.