Effects Of Different Planting Methods On Growth And Development,Yield And Quality Of Early-late Season Cultivars In Double Cropping Rice

To explore the effects of different planting methods on growth characteristics and yield of double cropping rice, field experiments with conventional early rice Zhongjiazaol7and hybrid early rice Lingliangyou104 as materials in both early and late season were conducted in Changsha county in 2013 and Liuyang city in 2014 of Hunan province. The different planting methods were taken as the treatments:direct seeding (DS), hand transplanting (HT), seedling throwing (ST) and mechanical transplanting (MT). Field plots were arranged in randomized block design with three replications. Grain yield and yield components were measured at maturity stage and dry matter accumulation were measured at heading stage and maturity stage, and tiller dynamic, growth stage, the leaf area index (LAI), amount of photosynthetically active radiation (PAR) interception qualities of rice were measured a t key growth stages. The results were showed as follows:1.The yield of zhongjiazaol7 and lingliangyou104 among different planting methods were not significant in the early season in 2013, significant difference was found in late season, while it were significant difference in the early and late season in 2014.The yield of MT of the two varieties in early season was the highest and averaged as 9.17 t/hm2(8.28-10.10 t-hm"2). And the higher yield of both MT and HT in late season were 8.78～8.79 t·hm-2 in 2013, and the higher yield of DS and MT in 2014 were respectively 8.05-8.20 t·hm-2 and 7.79～8.03 t·hm-2. From the point of production throughout the year, the yield of MT of the two years was the highest (18.32t·hm-2 in2013,respectly 16.07 t·hm-2 and16.77t·hm-2 in 2014), HT is the second and the lowest was DS or ST.2.The effects of different planting methods on effective panicles,grains per panicle and the total amount of spikelets of the two varieties have reached significant level,little effects on seed setting rate and grain weight. Effective panicles of DS was highest in addition to MT was highest in the early season of 2014 and HT was lowest. While grain number per panicle showed the opposite trend, HT was highest,MT and ST arranged the second place,DS was lowest. The total amount of spikelets of ST was highest,MT was taken as the second place and DS was lowest in early season of 2013; MT of zhongjiazaol7 was highest,HT of lingliangyou was highest as well,all lowest by DS in early season of 2014, in the late season,DS was highest,MT was second and ST was lowest.3.The whole stages of two varieties were same under the same seeding stages and transplanting stages, but the years have differences. Plant growth period shortened 2-4d in early-late season cultivars in 2013, and in 2014 it shortened 11-22d. There was no significant difference of the total growth duration,heading stage and mature stage of early rice among the four planting methods, DS of late rice delayed sowing 13-15d and the total growth duration was shortened 5-8 d.4.The growth rate of the tiller number and highest tiller number of different planting methods showed in turn:DS>ST> HT>MT in the early season. However, in the late season, the death rate of tillers was presented in order:DS>ST> HT>MT. The tiller increase and decline of HT and ST appeared as the type of early onset steady rise and slow down, MT displayed the slow onset speed rise and slow down, the type of DS showed the speed onset speed rise and speed drop.5.The dry matter accumulation of heading stage and mature stage among different planting methods were different in year. In early rice of 2013, the dry matter accumulation of ST of heading stage and mature period of zhongjiazaol7 and lingliangyou1041ing was highest and reached significant level,DS and MT were arranged the second place,and HT was lowest, dry matter accumulation after flowering of total dry matter weight showed DS >ST>HT>MT; the dry matter accumulation of heading stage and mature stage presented in DS>ST>MT>HT, the same as dry matter accumulation after flowering in early rice.The dry matter accumulation of MT of heading stage of the two varieties was highest,HTand ST were taken as the second place,DS was lowest throughout the year in 2014.6.Brown rice and milled rice rate was no significant difference among different planting methods. The head milled rice rate of MT and AT were higher than DS and ST. The chalkiness rate of DS was highest,however,MT was lowest. The Chalkiness degree of DS and MT were smaller. Amylose content was DS>AT>MT>ST.As an above, adopting the combination mode of variety in early-late season and MT as well, it is benefit to the yield formation and the coordination among yield components and relieved the contradictions of growth douration of MT of double cropping rice. With the cropping planting mode, the MT can obtain higher yield (select appropriate varieties), higher effective panicle numbers and grain number per panicle and production factor was more coordinated, and the growth stage and the yield were more appropriate. Compared with the traditional manual transplanting, MT save work and save time and economized manual labor input. It was a high and stable yields technology and was the developing direction of rice in the future.