Effects of  Plant Density on Grain Number and Grain Weight at Different Spikelets and Grain Positions in Winter Wheat Cultivars Effects of Spikelet and Grain Positions on Grain Number, Weight and Protein Content of Wheat Spike Difference in Chalky Characters of the Grains at Different Positions within a Rice Panicle Comparisons of Several Nutritional and Cooking Qualities of Grains at Different Grain Positions of Panicle between Two Panicle Types of Japo- nica Rice Relat ionship Between RVA Profile Characteristics and Other Quality Traits in Grain Positions of Japonica Rice Effects of Exogenous ABA and GA on the Main Quality Characteristics of  Grains at Different Positions of Panicle in Rice