Abstract: Using early rice（Oryza sativa L.） widely used in production E′zao 18 as a donor of Ghd7 and taking the excellent mid-season recovery rice the department Yangdao 6 as the recurrent parent,a series of groups were constructed by backcross and self-crossing. Molecular marker detection using SSR marker RM5436 closely linked to Ghd7 in separation generation,combined with agronomic characters in the field,a number of strains with different backcross generations were obtained. Finally,some lines with similar agronomic characters to Yangdao 6 were selected. A series of agronomic characters such as heading date,plant height,effective ear number,panicle length,grain number per panicle,seed setting rate,1 000-grain weight,yield per plant（i.e. grain weight per plant） were investigated. The effect of Ghd7 on the improvement of rice growth stage and its effect on other agronomic characters were evaluated.

Key words: rice（Oryza sativa L.）, Yantao 6, E′zao 18;, Ghd7 genotype, growth period