Abstract: This paper studied the effects of shading in the period from jointing to maturit y on the grain yield, starch content, and starch paste traits of two winter whea t (Triticum aestivum L.) cultivars, shading-tolerant Yangmai 158 and s hading-intolerant Yangmai 11, and analyzed the relationships of the redistribu tion of total soluble sugars stored before anthesis in vegetative organs with th e grain yield, starch content, and starch paste parameters of the cultivars. The results showed that shading decreased the redistribution of pre-anthesis store d total soluble sugars in vegetative organs to reproductive organ, resulting in the decrease of grain yield, and significantly decreased the amylopectin content but had no effects on the amylose content in grains, inducing a significant dec rease in the ratio of amylopectin to amylase content in the grains. Shading also decreased the grain starch peak viscosity of the cultivars. Under shading, Yang mai 11 had a decrease of its grain starch through viscosity and an increase of s tarch pasting temperature, while Yangmai 158 had lesser responses in the two par ameters.

Key words: PASP-KT-NAA, accumulated temperature zone, grain-filling process, Heilongjiang Province of Northeast China.