0 (SAS Institute Inc., Cary, NC, USA). Broad-sense heritability (h2) was estimated with the formula MG-132 datasheet h2 = σg2 / σg2 + (σge2 / e) + (σe2 / re), in which σg2, σge2 and σe2 represent the genetic, genotype × environment and environmental variances, respectively; and e and r are the numbers of environments and repeats per environment. The linkage map and marker data for the RIL population were described in a previous study [31]. A total of 195 SSR and STS markers were used to construct the linkage map. QTL were detected by composite interval mapping (CIM) based on 1,000 permutation tests and a LOD score of 2.0 with the software QTL Cartographer v2.5. Map distances in centiMorgan units

were calculated from recombination values using the Kosambi mapping function. The correlation coefficients of A-type and B-type starch granule contents across three cropping seasons are presented in

Table 1. The contents of A-type starch granules or B-type starch granules among different years were positively correlated, RG7204 with the correlation coefficients in the ranges of 0.35–0.46 and 0.53–0.66, respectively. The contents of A-type and B-type starch granules in the same years were negatively correlated, with correlation coefficients of –0.72, –0.78 and –0.46 in 2006, 2011 and 2012, respectively. The mean contents of A-type starch granules of PH82-2 and Neixiang 188 were 79.9% and 82.6%, whereas the mean contents of B-type starch granules were 17.4% and 16.9%, respectively (Table 2). The mean contents of A-type and B-type starch granules in the RIL population

were 79.0% and 18.1%, with ranges of 65.7–89.0% and 11.9–28.2%, respectively. Although there were no obvious differences between PH82-2 and Neixiang 188, variation among RILs was significant with transgressive segregation observed in the RIL others population (Fig. 1), indicating polygenic inheritance. The analysis of variance for the 240 RILs showed that genotypes, years and their interaction had significant variances, and genotypes contributed to the largest component. Broad-sense heritabilities (h2) estimated for A-type and B-type starch granules were 81.2% and 87.3%, respectively. Three QTL for content of A-type starch granules were detected in the population (Table 3 and Fig. 2). Two QTL on chromosomes 1DL and 7BL were found in the 2012 trial, explaining 5.6 and 5.2% of phenotypic variation, with the increasing allele effects from Neixiang 188 and PH82-2, respectively. One QTL with the increasing allele effect from PH82-2 was located on chromosome 4AL in the 2006 trial, explaining 3.8% of the phenotypic variation. The LOD threshold for significance was 2.0. LOD scores are shown on the horizontal axes, and molecular markers and genetic distances (cM) are shown on the vertical axes. In previous studies, a major QTL for starch granule size distribution was mapped on group 4 chromosomes in Triticeae [23], [24], [25] and [26]. Although Qga.