The Formation Characteristics Of Direct-seeding Rice Population Productivity And Difference Of Varieties

In recently years, direct-seeding rice developed very fast in Jiangsu province, and now it has become one of the main cultivation methods that could not be ignored. The population growth characteristics such as yield and population formation of direct-seeding rice are very different from transplanting rice, but the specific research on these respects was little. Different types of japonica rice (yangfujing8, huaidao13and wuyujing3) were used in this study. Through different seeding rate and sowing method to establish groups of different types and research the yield performance, population development, plant morphology and rice quality. To analyze the cultivation adaptability and expressive characteristics of direct-seeding rice and discuss high yield population construction and effective way of high quality cultivation on direct-seeding rice. The main results are as follows:1. The different seeding rate were studied in two consecutive years, the results showed that the highest yield was gained when the seeding rate was3.0～3.5kg per667m2. Analysis of yield components, improving seeding rate could not significantly increase effective panicle number. The number of spikelet per panicle,1000-grain weight and filled-grain rate were high in suitable seeding rate. Both the number of spikelet per panicle and filled-grain rate showed a decline trend in higher seeding rate. These showed that the highest yield in suitable seeding rate was due to yield components showed better and comprehensive quality improved. Therefore, to achieve relatively large panicle type in suitable panicle is the main direction of the highest yield in direct seeding rice.2. Population development in different seeding rate displayed that initial growth situation of population tillering ability was stronger in higher seeding rate treatment (A2, A3, A4), dynamic development of stems and tillers appeared a larger landing trend. The peak seedling number increased with seeding rate, but higher seeding rate increased ineffective tillering and played limited role in effective panicle number. The spike rate was low. The material accumulation of three tested varieties was significantly different. In yangfujing8and huaidao13, whether individual dry weight or groups dry weight, they all showed increased first and then decreased. In wuyujing3. population dry weight significantly increased with seeding rate at jointing and heading stage, but in middle seeding rate it were highest at maturity. The results showed in suitable seeding rate, both individuals and population had higher dry matter production capacity, material production in solid stage is more, harvest index showed more suitable (0.50or so).3. With the increase of seeding rate, rice plants height increased, lodging resistance of plants was bad. In suitable seeding rate, the length of peduncle and length ratio of total were reasonable, the second basal internodes become thick, stem wall thickness were enhance, the number of vascular bundles and the area of vascular bundles were large, the structure of internode internal tissue were better. The content of usable carbohydrate in stem was high at maturity stage, and the content of cellulose, hemicellulose and lignin were high. These showed the supporting stem cell walls were strong, and lodging resistance of plants were high.4. Grain quality of directed-seeding rice was affected. The brown rice rate, head milled rice rate and full head milled rice rate were decreased in excessive seeding rate, chalky rice percent and chalkiness were increased, the rate of protein was somewhat reduced. In proper seeding rate, the kernel length, width, projected area and length/width were bigger, gel consistency was increased, Peak, Trough and Breakdown were increased. These showed processing quality, appearance quality, nutrition quality and RVA were improved in proper seeding rate. In row seeding, the brown rice rate, head milled rice rate and full head milled rice rate were increasing. Chalky rice percent, proportion of chalky and chalkiness decreased. The kernel length, width, projected area and length/width were better.5. Broadcast sowing and row seeding had effects on population development and grain yield. The yield of yangfujing8and huaidaol3had no significant effect in row seeding and broadcast sowing, but the yield of wuyujing3in row seeding was significantly higher than broadcast sowing. In row seeding, the spike rate of rice was high, LAI of later grain-filling stage increased and material production capacity was better. Material production in solid stage of yangfujing8and huaidaol3were fewer. In row seeding, the lodging resistance of there tested varieties were all higher than broadcast sowing, plant height decreased, the second basal internodes became thicker, vascular system of the second basal internodes developed and the content of usable carbohydrate of stem at maturity were high, thus improved lodging resistance of plants.