Effects Of Mechanical Sowing And Transplanting On Dry Matter Production, Yield, And Quality Of Hybrid Rice Cultivar

In order to explore the effects of mechanical sowing and transplanting methods on growth, yield, and quality of hybrid rice cultivar, the dry matter production, nitrogen accumulation and distribution, differentiation and retrogression of spikelets, yield and its components, starch and nutrition quality of rice were studied using F you 498 as test material with three sowing and transplanting methods, two seeding number per hill, and two sowing and transplanting dates. The field experiments were studied using two factorial split-plot designs in 2012 and 2013. The results showed as follows:1. The dry matter accumulation and distribution of rice were clearly influenced by different sowing and transplanting methods, and the interactions of different seeding number per hill, sowing and transplanting dates. The dry matter accumulation of population and rate in mechanical direct seeding were significantly higher than those in artificial transplanting at the stages from jointing to heading, and the exportation, export rate, transformation rate of stem-sheath tended to be significantly higher in mechanical direct seeding than those in mechanical transplanting and artificial transplanting. However, the population and rate of accumulation dry matter had enhanced in mechanical transplanting at the stages from heading to maturity, both the ratio of dry matter accumulation after heading to biomass yield and contribution rate of dry matter accumulation after heading in mechanical transplanting had enhanced as well. Whereas, the dry matter weight distribution ratio to panicle in artificial transplanting were significantly higher than that in mechanical direct seeding and mechanical transplanting. Moreover, the assimilation of dry matter after heading, ratio of dry matter accumulation after heading to biomass yield and contribution rate of dry matter accumulation after heading were increased by low seedling number per hill and early seeding treatments. It was found that the harvest index was clearly influenced by the interactions between sowing and transplanting methods, and sowing and transplanting dates, and it was increased in mechanical direct seeding and mechanical transplanting with early seeding, and in artificial transplanting with late seeding.2. There was a difference in the characterization of nitrogen accumulation and utilization in hybrid rice cultivar under different mechanical sowing and transplanting methods. The nitrogen accumulation rate and the ratio to total nitrogen accumulation at the stages from heading to maturity in mechanical direct seeding and mechanical transplanting were higher than that in artificial transplanting, and the mechanical direct seeding could keep a higher nitrogen increase in panicle. The nitrogen dry matter productivity and harvest index in the mechanical sowing and transplanting methods with low seedling number per hill were increased under a reasonable early sowing, however, the artificial transplanting with high seedling number per hill and early sowing kept a high nitrogen productivity and harvest index. The nitrogen translocation, apparent nitrogen translocation rate of rice leaf in mechanical sowing and transplanting methods were lower than that in artificial transplanting, however, the nitrogen translocation, apparent nitrogen translocation rate, and nitrogen translocate contribution rate of rice stem-sheath in mechanical sowing and transplanting methods were higher than that in artificial transplanting. Moreover, the partial factor productivity of applied nitrogen under different sowing and transplanting methods were different, artificial transplanting was the highest, followed by mechanical transplanting, mechanical direct seeding was the lowest.3. The numbers of survived primary and secondary branches and spikelets were significantly influenced by different sowing and transplanting methods, seeding number per hill, sowing and transplanting dates, and the interactions of different seeding number per hill, sowing and transplanting dates with sowing and transplanting methods. The numbers of differentiated primary branches and spikelets in mechanical sowing and transplanting methods were higher than that in artificial transplanting, however, the number of survived secondary branches and spikelets in mechanical transplanting were higher than artificial transplanting, while those in mechanical direct seeding were the lowest. The bottom and middle of the panicles more probably differentiated a higher number of secondary branches on the different primary branches in the different treatments. The number of the differentiated spikelets on the secondary branches increased to its peak value (on the 9-12 parts of primary branches) and then decreased on the different primary branches in all the cultivation methods. The numbers of survived primary and secondary branches and spikelets in high seedlings number per hill were lower than that in low seedlings number per hill, early seeding could enhanced the number of differentiated and survived secondary branches. The correlation between the numbers of survived secondary branches and spikelets, and the dry matter weight per stem of jointing and heading stage were significantly positively correlated, the same between the differentiated secondary spikelets and the dry matter weight per stem of jointing stage. However, the retrograded secondary branches had a significant negative correlation with dry matter weight of population. The numbers of differentiated and survived primary and secondary branches and spikelets were significantly correlated with the nitrogen content of jointing stage, but those were negative correlation with the nitrogen content of heading stage. The daily average temperature at the stages from booting to heading was significantly and negatively correlated with the numbers of survived secondary branches and spikelets, and it was also significantly and negatively correlated with the differentiated secondary spikelets. Furthermore, the whole and daily average rainfall at the stages from booting to heading correlated significantly with the retrograded secondary spikelets.4. The chalkiness area and chalkiness degree of hybrid rice were liabled to be varied by different sowing and transplanting methods, mechanical transplanting was the highest, followed by the artificial transplanting, and the lowest was the mechanical direct seeding. Compared with mechanical transplanting and artificial transplanting, the chalkiness rate of mechanical direct seeding was significantly lower, moreover the protein content of grains in artificial transplanting were significantly lower than that in mechanical transplanting and mechanical direct seeding. The milled rice rate and head milled rice rate of hybrid rice were liabled to be varied by interaction of sowing and transplanting dates and sowing and transplanting methods, and they were improved by mechanical direct seeding with early seeding and mechanical transplanting with late seeding. The trend of RVA profile characteristics were influenced by sowing and transplanting methods, seedlings number per hill and sowing and transplanting dates, therefore, the RVA profile characteristics could be enabled efficient coordination through properly adjusting the seedlings number per hill and sowing and transplanting dates.5. Different sowing and transplanting methods influenced the grains yield through changing the seed-setting rate, number of grains per panicle and panicle number, while the grains yield was positively correlated with total rainfall, total accumulated temperature and daily rainfall, significantly. Therefore, for the effect of interaction among different sowing and transplanting methods, seeding number per hill, and sowing and transplanting dates, the yield of hybrid rice cultivar in mechanical sowing and transplanting methods were enhanced with a reasonable increasing of the seeding number per hill and early sowing.