Abstract:From 2011 to 2012, a series of field experiments were conducted in Donghai county, Huaibei region of Jiangsu Province under typical annual rice-wheat cropping rotation system. Two conventional japonica varieties, Zhendao 11 and Yongyou 8, and two hybrid japonica varieties, Yongyou 1640 and Yongyou 2640, were grown under three mechanical transplanting methods, bowl-seedling, blanket-seedling, and direct-seeding mechanical-transplanting, to determine the diversity of seedling quality, growth duration, photosynthetic production, accumulated temperature and illumination hours, yield components, and grain quality. Results showed that the seedling quality of bowl0seedling of the mechanical transplanting rice was significantly better than that of blanket-seedling mechanical transplanting rice. Compared with bowl-seedling of the mechanical transplanting rice, each growth period were postponed in blanket-seedling mechanical transplanting rice and direct-seedling mechanical transplanting rice, and whole growth period was shorted about 8~10d and 20~22d, respectively. Accumulated temperature and illumination hours of whole growth period and different growth stages were lower, and then led significantly lower crop growth rate and net assimilation rate in mid-to-late growth period. The yield of bowl-seedling mechanical transplanted rice was the highest and the yield of direct-seeding mechanical transplanted rice was the lowest. Yield components of bowl-seedling mechanical transplanted rice had the characteristics of significantly less number of panicle per unit area, significantly higher spikelets per panicle and kilo-grains weigh, and bowl-seedling mechanical transplanted method significantly increased grain yield by 10.2% and 23.4% than blanket-seedling and direct-seeding mechanical-transplanting method in hybrid rice, respectively, and by 5.6% and 19.3% in conventional rice, respectively. Moreover, grain quality of bowl-seedling mechanical transplanted rice was the best. Studies indicate that bowl-seedling mechanical transplanted method is a priority selection in Huaibei area.
