Mapping Quantitative Trait Loci for Post-Anthesis Dry Matter Accumulation in Wheat

Post-anthesis photoassimilation is very important for wheat (Triticum aestivum L.) grain filling. The aim of the present study was to map quantitative trait loci (QTL) for post-anthesis dry matter accumulation (DMA).A set of 120 doubled haploid (DH) lines, derived from winter wheat varieties Hanxuan 10 and Lumai 14, was grown under field conditions in two consecutive growing seasons during 2002-2004 in Beijing. Post-anthesis DMA per culm and related traits, including flag leaf greenness (FLG) and flag leaf weight (FLW; dry weight per flag leaf) at flowering, and grain weight per ear (GWE) were investigated. All traits segregated continuously in the DH population in both trials. The DMA was significantly and positively correlated with GWE, with the correlation coefficients being 0.79 and 0.66 in the 2002-2003 and 2003-2004 growing seasons (both P ＜ 0.01), suggesting the importance of DMA in grain filling. Further correlation analysis showed that FLW was more closely correlated with DMA and GWE than FLG in both growing seasons, indicating that FLW was more important than FLG in influencing DMA and GWE. In total, 30 QTLs for these four traits were mapped and distributed on 10 chromosomes. Phenotypic variations explained by an individual QTL were in the range 5.8%-21.3%, 5.9%-17.2%, 5.1%-18.1%, and 5.6%-16.2% for FLG, FLW, DMA, and GWE, respectively.Eight QTLs for DMA were detected, of which four (on chromosome arms 2AS, 4BL, 5AS, and 7AS) were linked with QTLs for GWE; two (on chromosome arms 5BL and 7BL) coincided with QTLs for FLW. These results may provide useful information for developing marker-assisted selection for the improvement of DMA.