半高秆超级杂交稻根际微生物对产量的影响机理及高产调控研究

Super hybrid rice with semi-tall stalk is a new concept put forward by Mr. Yuan Longping in 2012 based on the regulation of increase of rice yield and change of plant height during the past several decade and the summary of successful experiences of high yield trails of super hybrid rice in recent years. Its harvest index is about 0.5, yield is 14～15t/hm2 and plant height is 1.3～1.4m. Super hybrid rice with semi-tall stalk has bigger biomass and higher yield potential, so it demand stronger roots. The influence mechanism of the rhizosphere microorganisms on yield of rice was studied by processors, while the rhizosphere microorganisms was not studied under yield level above 14t/hm2. In this study, the relationship between community structure, diversity, abundance and activity of rhizosphere microorganisms and yield will be studied under high-yielding condition in high-yielding biological area and common biological area with super hybrid rice with semi-tall stalk as materials to prove the change law of rhizosphere microorganisms under different nitrofen rates, microbial fertilizer control, chemical control and water management conditions, and then construct the response model of rhizosphere microorganisms-agricultral measures-rice yield to provide the theoretical basis and technical support for realization of yield index of super hybrid rice with semi-tall stalk.

半高秆超级杂交稻是袁隆平院士基于数十年来我国水稻产量的提高和植株高度变化的规律，总结近年来超级杂交稻高产攻关成功经验，于2012年提出的新概念。要点是水稻收获指数保持0.5左右，产量指标在14～15t/hm2，株高在1.3～1.4m。半高秆超级杂交稻生物量大，产量优势明显，需要强大的根系。对水稻在常规产量条件下根系及根际微生物对产量的影响机理前人有过研究，但未有人对14 t/hm2及其以上产量条件下根际微生物进行过研究。本研究以大田种植的半高秆超级杂交稻为研究对象，研究高产生态区高产条件下和一般生态区高产条件下半高秆超级杂交稻根际微生物群落结构、多样性、丰度和活性与产量的相关性，探明不同施氮水平、微生物肥调控、化学调控和水分管理等条件下半高秆超级杂交稻根际微生物的变化规律，建立水稻根际微生物- 农艺措施- 水稻产量响应模型，为半高秆超级杂交稻产量指标的实现提供理论依据和技术支撑。

比较半高秆超级杂交稻在高产生态区和一般生态区的产量与根际微生物群落结构、多样性、丰度及其相关性，探明施氮量、微生物肥、栽培方式对其根际微生物的影响，以期建立根际微生物-农艺措施-产量响应模型，为半高秆超级杂交稻产量指标实现提供理论与技术支撑。.比较了半高秆超级杂交稻在高产区与低产区的根际土壤微生物群落结构。利用IlluminaMiSeq高通量测序技术对高产区和低产区超级稻移栽前、分蘖期、抽穗期、收获期的土壤进行16S rDNA分析，发现：高产区超级稻生育期间土壤微生物多样性显著大于移栽前，而低产区各时期间差异不大。两个生态区的共同优势细菌为Proteobacteria、Acidobacteria、Chloroflexi和Verrucomicrobia，而Bacteroidetes为高产区特有优势类群。Chloroflexi在低产区相对丰度显著大于高产区，Bacteroidetes和Proteobacteria表现相反，而Acidobacteria和Verrucomicrobia在两个区的相对丰度差异不显著。低产区古菌数量显著大于高产区，低产区和高产区相对优势古菌群分别是Crenarchaeota和Euryarchaeota。随生育期推进，Crenarchaeota、Euryarchaeota、Acidobacteria和Verrucomicrobia的相对丰度先减后增，Bacteroidetes和Proteobacteria呈下降趋势，Chloroflexi呈先升后降趋势。RDA分析表明，Proteobacteria的动态变化主要受有机质含量影响，而Bacteroidetes主要受土壤速效磷驱动。高产区和低产区细菌和古菌群落动态变化的主控因子分别是土壤速效氮和速效磷。可见超级稻高产区和低产区土壤细菌和古菌群落结构差异明显，且其主要影响因素是土壤速效养分含量。.研究了品种、栽培方式、施氮量与微生物肥对超级稻产量与土壤微生物群落结构的影响。海南超级稻品比试验表明，品种间产量差异明显，Y两优900最高，深两优1813最低。研究表明，不同栽培方式、施氮量与微生物肥条件下，超级稻根际微生物群落结构差异均不显著。.探索了半高杆超级杂交稻根际土壤微生物种群丰度与产量的关系。但大田试验影响因素太多，尚没有得出土壤微生物与超级稻产量关系的规律化公式，还需进一步研究。