Yue Bing, Xiong Lizhong, Xue Weiya, Xing Yongzhong, Luo Lijun, Xu Caiguo
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China.
Theor Appl Genet. 2005 Oct;111(6):1127-36. doi: 10.1007/s00122-005-0040-1. Epub 2005 Oct 11.
Drought resistance of rice is a complex trait and is mainly determined by mechanisms of drought avoidance and drought tolerance. The present study was conducted to characterize the genetic basis of drought resistance at reproductive stage in field by analyzing the QTLs for drought response index (DRI, normalized by potential yield and flowering time), relative yield, relative spikelet fertility, and four traits of plant water status and their relationships with root traits using a recombinant inbred population derived from a cross between an indica rice and upland rice. A total of 39 QTLs for these traits were detected with individual QTL explained 5.1-32.1% of phenotypic variation. Only two QTLs for plant water status were commonly detected in two environments, suggesting different mechanisms might exist in two types of soil conditions. DRI has no correlation with potential yield and flowering time under control, suggesting that it can be used as a good drought resistance index in field conditions. The co-location of QTLs for canopy temperature and delaying in flowering time suggested a usefulness of these two traits as indexes in drought resistance screening. Correlation and QTL congruence between root traits and putative drought tolerance traits revealed that drought avoidance (via thick and deep root traits) was the main genetic basis of drought resistance in sandy soil condition, while drought tolerance may play more role in the genetic basis of drought resistance in paddy soil condition. Therefore, both drought mechanisms and soil textures must be considered in the improvement of drought resistance at reproductive stage in rice.
水稻的抗旱性是一个复杂的性状，主要由避旱机制和耐旱机制决定。本研究通过分析干旱响应指数（DRI，以潜在产量和开花时间进行标准化）、相对产量、相对小穗育性以及植物水分状况的四个性状的QTL，并利用一个由籼稻和旱稻杂交衍生的重组自交群体分析它们与根系性状的关系，来表征田间生殖阶段抗旱性的遗传基础。共检测到39个控制这些性状的QTL，单个QTL解释的表型变异为5.1%-32.1%。仅在两种环境中共同检测到两个控制植物水分状况的QTL，这表明在两种土壤条件下可能存在不同的机制。在对照条件下，DRI与潜在产量和开花时间无关，这表明它可以作为田间条件下良好的抗旱指标。控制冠层温度和延迟开花时间的QTL共定位表明，这两个性状作为抗旱筛选指标具有实用性。根系性状与假定的耐旱性状之间的相关性和QTL一致性表明，在砂质土壤条件下，避旱（通过粗壮和深扎的根系性状）是抗旱性的主要遗传基础，而在水稻土条件下，耐旱性可能在抗旱性的遗传基础中发挥更大作用。因此，在提高水稻生殖阶段的抗旱性时，必须同时考虑干旱机制和土壤质地。
