Study on Seedling Quality of Double-cropping Late Rice Sowed at Different Dates in Guangdong

[Objective]The aim was to study seedling quality of rice sowed at different dates so as to provide theoretical basis for determining the best seeding time.[Method]By investigating the characters of shoot and root of different varieties sowed at different dates,the best seeding time of double-cropping late rice was determined.[Result]The first leaf sheath height and the second leaf length shared significantly positive correlation,which fit the quadratic equation well.The effects of different sowing dates on shoot and root of three rice varieties appeared significant difference.[Conclusion]The best seeding time of Tianyou 428 was durirg June 25-July 2 and that of Tianyou 998 and Yuxiangyouzhan was during July 2-9.