华南高产优质稻耐热生理生态机制与遗传基础研究

Southern China double cropping rice region with abundant resources of water, light, heat, and genetic materials, perennial accounting for about 17% of the total rice area of China, is one of the main supply region of perfect quality rice for China. However, as for the global warming becomes serious, the extreme high temperature breaks out more frequently as the meteorological disasters, heat stress of high temperature has become one of the important factors that impacts rice yield and quality. Heat stress mainly damages the pollination and fertilization of rice during the flowering phase, which decreases the spkilets fertilizer and results in remarkable yield drop. With the basis of primer study of rice heat tolerance evaluation at flowering stage, this project attempts to conduct systematic experiments to investigate the characteristics of growth and development, flowering habit, pollination and fertilization character, thermostability of floral organ, physiological and biochemical response to the abiotic stress, yield components, and other aspects of the high yield perfect quality rice in Southern China under high temperature heat stress conditions. The genotype differences of heat tolerance and heat escape to heat stress during the flowering will especially focused on by this project, and it will to screen and identify heat tolerance high yield perfect quality varieties or materials, and explore the relationship between the maintain development of pollination and fertilization of the resistant physiological and biochemical characteristics with the spkilets fertilizer character under high temperature stress, elucidate the ecophysiological mechanism of heat tolerance to high temperature. Meanwhile, dissect the genetic mechanism of heat tolerance using the quantitative genetics methods. This project will provide a scientific basis for the rice disaster reduction cultivation of heat damage, heat resistant breeding, and disaster assessment of high-temperature in Southern China double cropping rice region.

华南双季稻区，常年种植面积约占全国稻作总面积的17%，水、光热、遗传资源丰富，是中国优质稻米的主要供给地之一。然而，随着全球变暖，局部区域极端高温气象灾害频发，高温热害已成为限制其水稻产量与影响米质的重要因素之一。高温热害主要影响水稻花期授粉受精，导致结实率下降，产量锐减。项目在前期研究花期耐热性鉴定筛选的基础上，拟通过在高温热害胁迫条件下对华南高产优质稻耐热品种材料的开花习性、散粉特征、花器官热稳定性与抗逆响应的生理生化特性、产量构成等方面的系统研究，重点明确基因型间耐热与避热的差异，筛选鉴定出耐热高产优质品种材料；探明高温胁迫下的授粉受精抗逆发育维持的生物学特性与颖花结实性的关系，阐明耐热生理生态机制；同时采用数量遗传学的方法剖析耐热品种颖花结实的遗传基础；为华南双季稻区水稻生产热害减灾栽培、耐热育种以及高温热害灾害评估提供科学依据。

本项目研究围绕水稻开花结实期高温热害引起的水稻籽粒结实率下降，在评价华南高产优质稻主导品种耐热性和深入系统研究不同水稻基因型耐热机理基础上，完善了水稻耐热害鉴定方法，鉴定评价了华南高产优质稻品种的耐热生理生态特性，筛选出耐热品种和高温敏感型品种；同时基于本研究中所获得的后代群体材料初步定位到水稻花期耐热QTL位于第8染色体。对照考核指标，本项目较为圆满地完成了课题任务书要求的各项指标。