Effects of Source Strength and Sink Size on Starch Metabolism, Starch Properties and Grain Quality of Rice (Oryza sativa L.)

The source strength and sink demand as well their interaction have been demonstrated to co-regulate the synthesis of starch determine grain quality, but knowledge underlying physiological mechanisms is limiting. An indica variety, Yangdao 6, a japonica Jinxiangyu 1, were planted with three treatments, including normal growth plant (CK), leaf-cutting (LC) spikelet-thinning (ST). transcript levels metabolic genes, physicochemical characteristics appearance, milling, cooking tasting qualities rice under different treatments determined. ST treatment increased relative expression genes related short branch-chains amylopectin (SSI, BEI, BEIIb) amylose (GBSSI) reduced medium-long long (SSIIa, SSIIIa, SSIIIb, ISA1). When comparing CK treatment, granules became smoother higher contents lower ratios amylopectin; crystallinity value 1045/1022 cm−1 was decreased; for pasting properties, setback temperature peak viscosity, hot breakdown final viscosity significantly increased. Meanwhile, improved milling qualities. opposite results observed LC treatment. These indicated that size would regulate which pivotal short/long branch chains ratio amylopectin, thus changing structure properties quality. Here, we speculated in terms leaf/canopy photosynthesis small size, such panicle be preferred traits high quality breeding.