Effects Of Direct-seeding Date On Yield Formation And Quality Of Different Genotypes Of Rice In Taihu Region

The field experiments were conducted in Changshu institute of agriculture science, Jiangsu Province at Taihu region in2009～2010. Conventional late-maturing medium japonica (CLMMJ)、Conventional early-maturing late japonica (CEMLJ)、Conventional medium-maturing late Japonica (CMMLJ)、and Hybrid medium-maturing late Japonica (HMMLJ) as experimental material, study different sowing date (May27, June3, June10, June17, June24, July1) on the different types of species Growth period,reproductive period of accumulated temperature, yield, Nitrogen accumulation, and quality in the wheat stubble. In order to produce high quality and high yield for the direct sowing rice at Taihu region and rational utilization of natural resources efficiently to provide theoretical and practical basis. The main results are as follows:1. The yield and its varieties constitute factors was decreased following the lateness of the seeding time,the slower sowing date,the lower yield; the yield decreasing caused by the decline of spikelets per panicle and filled grain percentage, panicles and1000-grain weight had a little change. Under the condition of the same seeding period, there were difference in yields and yield formation of different rice varieties, the total yield of HMMLJ was the highest, CMMLJ were secondly, and CEMLJ was the lowest.2. The different varieties were all showed that heading stage delayed and the whole growth period become shorter following the lateness of the seeding time. The treatment of seeding in May27was the longest and in July1was the shortest; every sowing delayed7days, the whole growth period shorten4-5days. The difference of Growth period length mainly lies in the sowing-jointing days, but apparently, jointing-heading and heading-riping days’differences were very little. Therefore, the difference of the whole growth period in different types variety depended mainly on the days before heading of rice varieties.3. Accumulated temperature and sunshine time of the sowing-heading in different rice varieties were decreased following the lateness of the seeding time; The treatment of seeding in May27was the highest and in July1was the lowing.But the accumulated temperature and sunshine time of the heading-riping differed not quite. Meanwhile, the utilization ratio of accumulated temperature in different rice varieties were reduced greatly following the lateness of the seeding time.4. There were difference in forming production dynamic of different rice varieties, such as tille dynamics, LAI dynamics, dry matter accumulation and internode collocation, etc. The treatment of seeding in May27behaved the best and in July1behaved the worst.5. Plant N rate、N accumulation quantity and period N accumulation quantity were decreased following the lateness of the seeding time.The difference between different variety types was not significant.6. 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, 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 the different effect, milling quality of the type of CLMMJ and CEMLJ became better but worse the nutrient quality,milling quality of the type of CMMLJ and HMMLJ became worse but better the nutrient quality. Different varietise along with the deladyed sowing date, Peak vise、Hot vise、Breskdown、Final visc are gradually reduced; Pasting temp rising, but Peak vise time and Initiative pasting temp had no obvious increase or decrease the trend.The above results show that direct seeded rice at Taihu region in general should be chosen CMMLJ and HMMLJ. Early direct sowing is Co-ordinate to achieve high yield, high quality, efficient, ecological, security and other key technology integrated measures of production goals.