Abstract: After 4 years' study with both old and new winter wheat varities planted in Beijing since 1949,the results could be summarized as follows.(1) The harvest index of new varieties was about 11.72 percent points higher than that of old ones,but the ratio between grain weight and straw (leaf and culm) weight of new varieties was 83.9% higher than that of the old ones.This indicated a high sink source ratio and a higher efficiency in translocation of photosynthetic products.(2) As the genetic improvement was going on,single stalk biomass was enhanced,the culm became stronger,ear and grain became larger and it could bear more grains per spiklet,but the number of total spikes per unit area and the height of plant got lower.(3) In the progress of variety evolution,a negative genetic correlation coefficient among traits was found,while their corresponding environmental correlation coefficient were almost all positive.It indicted an inconsistency between the genetic correlation of characters and the pure biological correlation in the individual development.(4) Compared with the environmental variance some traits such as the height of plant,and the weight of ear and grain had bigger coefficient of genetic variance and were apt to genetic improvement through selection.It is necessary to improve the development,photosynthetic production,and translocation of original organic compound,in order to raise biomass production.

Key words: Winter wheat, Biomass, Genetic improvement

CLC Number: 

• S512.110.32