Effect of Plant Density on Sugar Content and Starch Accumulation in Grains of Two Winter Wheat Cultivars with Different Spike Types

In order to evaluate effects of planting density on the sucrose content,the soluble sugar content and the starch accumulation in grains of winter wheat,field experiments were carried out in growth season during 2004~2005 by using two winter wheat cultivars,Yumai 49-198,a multi-spike wheat cultivar,and Lankaoaizao 8,a large-spike wheat cultivar.The results indicated that the sucrose content and the soluble sugar content in grains of two wheat cultivars decreased in grain filling stage,while the starch content in grains increased.Under the field experimental conditions,effects of planting density on the dynamic changes of sugar content and starch accumulation in grains were different between the two cultivars: for Yumai 49-198,the planting density of 225×10~4 plants/hm~2 was favorable to the transformation of sucrose and the soluble sugar,the accumulation of grain starch and the 1000-grain weight were promoted obviously.As for Lankaoaizao 8,the planting density of 375×10~4 plants/hm~2 is advantageous in transforming sucrose and the soluble sugar in grain filling stage,then the starch accumulation and the 1000-grain weight were improved.The result also indicated that the dynamic change of 1000-grain weight was coincident with starch accumulation in grains.Thus,in practice,suitable planting density should be determined according to the accumulation characteristics of sugar and starch to increase grain yield.