Effects of Direct-seeding Date on Growth Period and Grain Yield of Different Genotypes of Rice

The relationship between seeding time of direct seeding rice and growth period,the grain yield formation was studied with different rice varieties.Experimental results showed that when sowing seeds on June 17(similar to the local seeding time),the grain yield of early mature medium japonica variety had the highest yield,and it had certain advantage in yield when time was short;when sowing seeds on July 1(the latest seeding time with the lowest yield),the yield of hybrid late mature medium japonica variety was the highest.Therefore,this hybrid combination has potential of high yield.The results also indicated that the seeding time of direct seeding rice have significant effect on grain yield.Seeding time is the base of high yield,so the suitable seeding time should be made according to the variety characteristics.Growth period of rice was affected by seeding time of direct seeding rice,and it was also an important factor for decreasing yield caused by postponement of seeding time.