Differences in chemical and structural properties of A-type and B-type starch granules lead to different functionalities. It was reported that higher proportions of smaller granules increased dough elastic properties [17]. B-type granules bind more water, which likely increases dough stiffness and reduces the elasticity [18]. The processing ability

and the qualities of both dried and cooked starch noodles made from small-sized granule fractions are much better than those made from large-sized granule fractions [19], but small A-type granules (about 12 μm) can increase bread weight [20]. When A-type and B-type compound screening assay starch granules were remixed in various proportions, the optimum proportion of B-type granules for superior bread quality was 25–35% by weight [21]. On the other hand, environmental factors influenced starch size distribution, but cultivars played a major role [22]. Therefore, it is necessary to study the genetic factors influencing starch size distribution. A few QTL studies Ku-0059436 in vivo of starch granules have been done in Triticeae crops. A major QTL was identified on chromosome 4S of Ae. peregrina for the content of B-type starch granules, accounting for 44.4% of the phenotypic variation [23]. A QTL for A:B ratio was detected on wheat chromosome 4B [24]. A QTL was found on barley chromosome 2 (2H), affecting

A-type granules and the mean F-shape of B-type granules, and two others on chromosomes 4 (4H) and 7 (5H) affected the mean F-shape of B-type granule and the mean

maximum diameter of A-type granules, respectively [25]. In addition, QTL were localized for granules < 5.0 μm, 5.1–10.0 μm and > 28.0 μm on chromosome 4DS and for granules 10.1–15.0 μm on 7AS and 1BL [26]. However, there is no consistent major QTL controlling starch granule size or distribution, and no study on QTL mapping of starch granule size distribution in Chinese wheat cultivars has been carried out. Thus any association of starch granule type and Chinese dry noodle properties remains unknown. The aim of the present study was to map QTL for differences tetracosactide in wheat starch granules using a RIL population derived from a PH82-2/Neixiang 188 cross, and to identify closely linked molecular markers. PH82-2, a hard wheat released in Shandong, China, is suitable for making Chinese noodles and steamed bread, whereas Neixiang 188, a soft wheat released in Henan, is known for its broad adaptation. Both of them have wild type non-waxy protein genes. The 240 recombinant inbred lines (RILs) generated from a PH82-2/Neixiang 188 cross were used for QTL mapping of starch granule size distribution. Field trials were conducted in a latinized alpha lattice design [27] with three partial replications at Anyang, Henan, China, in the 2005–2006, 2010–2011 and 2011–2012 cropping seasons.