Effects of Sowing Date on Yield and Quality of Direct Seeding Rice of Different Types and Varieties

【Objective】 The objective of the study is to elucidate the effect of sowing date on grain yield and its quality of direct seeding rice.【Method】 Taking six representative rice cultivars of three types as experimental materials,the yield formation and main rice quality traits of direct seeding rice growing under the conditions of different sowing date were analyzed.【Result】The results showed that along with the delayed sowing date,the yields of three types of rice cultivars were all significantly decreased,and the changing degree was different;the yield decreasing caused by the decline of spikelets per panicle and filled grain percentage,panicles and 1000-grain weight had a little change.The law of changing of main direct seeding rice quality traits between different types under the conditions of different sowing date showed some similarities and differences.Along with the delayed sowing date,the appearance quality and cooking and eating quality had the same effect,but the trend was different,appearance quality became better while cooking and eating quality became worse.Milling quality and nutrient quality had different effects,milling quality of the type of medium-maturing and late-maturing medium japonica rice became better but worse the nutrient quality,milling quality of the type of early-maturing late japonica rice became worse but better the nutrient quality.【Conclusion】 The direct seeding rice should be sowed as early as the time for harvesting the previous crop allows to attain high yield and improve cooking and eating quality,but reduce the appearance quality.Effects of sowing date on milling quality and nutrient quality were different because of types and varieties.