利用Ghd8与Ghd7等位基因组合探索南方稻区两季水稻品种的优化配置

The summer in the southern rice growing region of China is long and hot, so two season cultivations is suitable for rice. The delay in flowering time of rice will increase number of grains per panicle leading to the increase of yield. However，when sum of two growing periods of two rice varieties exceeds the length of summer, total yield of two-rounds planted rices will be affectted . So, the success of two season cultivations needs reasonable disposition of rice varieties of different flowering time. At present, how to achieve the maximization of total yield in two season cultivations by reasonable genotypes of rice varieties collocation is an urgent problem to be solved. The previous research of this project found that hybrid rice restorer line Shuhui 527 carry a non-functional allele. The variety produced by Shuhui 527 carrying ghd8/ghd8 has the phenotype of early flowering and less number of grains per panicle , which is as two-season rice cultivated in southern rice growing region. Further, this project attempts to explore the genetic relationship between Ghd8 and Ghd7 and combination of allele polymorphism, and compare the relationship between disposition strategy which rice varieties with different Ghd8 and Ghd7 allele combinations in two-season rice and total yield. The regression model was established based on statistical data according to Ghd8/Ghd7 combination to forecast rationality of different rice varieties collocation for two season cultivations, in order to ultimately achieve the maximum utilization of environmental resources.

中国南方稻区的夏季长、温度高，水稻通常进行两季种植。而水稻开花时间的延长会增加每穗粒数从而提高单季产量。但是，如果两季水稻的生育期总和超出夏季时长会影响两季总产量。所以，合理搭配两季水稻品种的开花时间是两季种植高产的关键因素。目前，如何在两季稻栽培的过程中，通过水稻品种的基因型合理搭配种植并取得总产量的最大化是亟待解决的问题。本项目的前期研究发现杂交水稻恢复系亲本蜀恢527携带一个没有功能的ghd8等位基因。由蜀恢527产生的携带ghd8/ghd8的品种具有早开花和少穗粒数的表型，并被作为两季稻在中国南方稻区种植。进一步本项目拟通过探索Ghd8和Ghd7遗传关系和等位基因组合多态性，并比较不同Ghd8和Ghd7等位基因组合的水稻品种在两季稻中的配置策略和总产量的关系。利用统计数据建立回归模型根据Ghd8/Ghd7组合预测不同水稻品种搭配两季种植的合理性，最终达到环境资源利用最大化。

水稻光周期开花网络对于水稻的生产和应用至关重要，决定了水稻的适应性与产量。本项目主要研究水稻光周期开花网络的等位基因组合在中国南方稻区的优化配置。我们获得如下重要结果：.1. 我们发现水稻光周期开花通路中的蛋白复合体DTH8-Hd1在调控Hd1长短日照的功能转化中的作用机制。.2. 我们发现Ghd7、DTH8和Hd1等位基因组合对于杂交籼稻品种的广适应性至关重要。尤其，Ghd7Hd1dth8基因型组合是一种杂交水稻品种优化配置的方案，同时兼具了产量和适应性，可以在将来的育种中推广应用。. 本项目的顺利实施成果的解析了Hd1功能转换的分子机制，并找到一种杂交水稻品种的优化配置方案。整个项目实施的过程中，从分子机制出发，完美的揭示了杂交水稻品种广适应性与光周期等位基因组合的关系，为水稻的分子设计育种提供了重要的理论基础和应用策略。