Effects of Spikelet and Grain Position on Grain Weight and Starch Property of Winter Wheat Varieties

The grain number and weight in different spikelet positions significantly varied with wheat cultivars.Little is known about starch properties of grain within the spike of winter wheat.This knowledge is important for determining breeding strategies aimed at increasing grain yield without affecting grain quality.An experiment using three winter wheat varieties with different 1000 grain weight was performed under field conditions.Grain weight,starch content and paste properties were determined.The results showed that grain weight of central and basal spikelet is higher than that of apical spikelet.For the basic and central grain-set spikelet,grain weight in G2 position was the highest, followed by that in G1 and the third grain G3 positions while grain weight in G1 position was higher than that in G2 position,then that in G3 position for the top grain-set spikelet.Grain of 2nd position had bigger contribution in improving spike weight.For Yumai 2 and Zhoumai 18,Amylose content of apical spikelet was the highest,while amylose content of central spikelet for Zhengyumai 9987 showed the highest value.Amylose content in grain at G3 position showed the highest value. The peak viscosity and breakdown viscosity of grain in central and basal spikelet is lower than that of apical spikelet.The highest value was observed of grain in G3 position.In wheat breeding and cultivation, as for wheat cultivars for different end-use quality(increasing yield and improving quality can be obtained simultaneously through controlling yield component.