Progress in Research of Yield Formation of Ratooning Rice and Its High-Yielding Key Regulation Technologies
XU Fu-xian;XIONG Hong;ZHANG Lin;ZHU Yong-chuan;JIANG Peng;GUO Xiao-yi;LIU Mao;Rice and Sorghum Institute, Sichuan Academy of Agricultural Sciences/Key Laboratory of Southwest Rice Biology and Genetic Breeding,Ministry of Agriculture;Luzhou Branch of National Rice Improvement Center;
The development of ratooning rice is a vital way to achieve a full utilization of the solar-thermal resources in autumn,and promote the profit of rice field. On the basis of the reported data and the research results of the author's study for more than 20 years, the research reviews and the research progress of yield formation mechanism and key control techniques of ratooning rice were summarized. The main results include that:(1) Compared with the lower regeneration buds, the mid-upper regeneration buds of main crop had an earlier heading date, a fewer number of leaves, a faster speed of leaf emergence, shorter growth period, higher bearing panicle rate and grain filing percentage. The mechanism of a large number of regeneration buds' death after full heading of main crop was mainly due to main photosynthate allocation to grains and fewer to regeneration buds during the main crop grain filling period. Regeneration bud growth depends upon not only the improved light condition at the base of main crop plant population,but also the biomass supply. The difference in ratooning ability among cultivars varied with the leaf-grain ratio of main crop. The higher the leaf-grain ratio at heading stage, the more the photosynthetic matter remained in the basic stems for ratooning rice growing at harvesting date of main crop, as a consequence, the better ratooning ability was gained as well. There was a high and significant negative correlation between the ratooning ability and the spikelets per panicle among varieties.(2) The ratooning ability could be divided into 4 stages based on the sink-source characteristics of the main crop and grain yield of ratooning rice. The high-yielding cultivars for main crop and ratooning rice would have the following sink-source traits:160-190 spikelets per panicle, the ratio of leaf area to grain weight 0.0737-0.0827 cm2 per mg, panicles 232.12×104-249.40×104 per ha, grain filling percentage 81.54%-85.74%,1000-grain weight 28.58-30.07 g, and grain weight 4.13-4.43 g per panicle.(3) The reason why N applying for bud development(NABD) was beneficial to increasing grain yield of ratooning rice is that N application delayed the functional leaves senescence of main crop at the late grain filling stage, improved nitrogen content of leaf and net photosynthetic rate of main crop, increased ratio of leaf photosynthetic products flowing into panicle, reduced the amount of photosynthetic products from initial storage in main stem input panicle, relatively improved stem-sheath dry weight and enhanced ratooning ability of main crop. The difference of the effects of NABD on ratooning rice varied with rice cultivars. By applying more NABD at an earlier stage, for the main crop with large panicle(higher spikelets per panicle), the grain yield of ratooning rice could be increased. The optimum date of NABD is about at full heading of the main crop. The method of estimation of efficient rate of NABD using chlorophyll meter reading(SPAD value) of flag leaf at the full heading stage of main crop in mid-season hybrid rice was found. The protection basal leaves of main crop by controlling sheath blight and enhancing root activity through reduction of paddy soil moisture posed an important assurance of high yield for ratooning rice. There was a significant and positive correlation between ripe degrees of main crop and ratooning ability. The optimum harvesting date is at complete ripe date for grains of main crop. The appropriate height for cutting seedlings is at 5-7 cm above 2nd node from the top of mother stem.(4) Aiming at the main factors restraining ratooning rice production, for example, lower temperature at heading stage of ratooning rice, a big yield gap existed among ratooning rice production areas, and the bad effect that machine harvesting main crop had on ratooning rice production, solutions to above the problems were put forward accordingly.(5)The research focus on theory and technology of ratooning rice in the future was pointed out. First, multi-factor interaction mechanism of ecological conditions and agronomic practices on canopy characteristics after full heading stage of main crop and regeneration bud growth. Second, the main cause of regeneration bud stagnation after main crop harvesting and its regulation approach. Third, the technology approach for improving nitrogen use efficiency of ratooning rice. Fourth, the study on the techniques of hybrid rice-ratooning rice's adaption to machinery transplanting and harvesting.
【Fund】： 农业部公益性行业科研专项(200903002 201003016);; 科技部重大科技支撑专项粮食科技丰产工程(2011BAD16BO5-1);; 国家水稻产业体系(CARS-01)
【CateGory Index】： S511
【CateGory Index】： S511