利用双向导入系解析水稻抽穗期和株高QTL及其与环境互作表达的遗传背景效应

利用粳稻Lemont和籼稻特青相互导入构建的遗传背景基本一致的双向回交导入系群体，分别在北京和海南环境定位影响抽穗期和株高的主效QTL及其环境互作，分析QTL及其与环境互作表达的遗传背景效应。在北京和海南分别检测到影响抽穗期和株高的主效QTL 16个和17个，其中有5个主效QTL (QHd2、QHd8a、QPh3、QPh5和QPh12)在两种背景下同时被检测到，表明多数主效QTL的表达具有遗传背景特异性。两种背景下检测到影响抽穗期的3个主效QTL (QHd8a、QHd9和QHd10b)存在环境互作，其中QHd8a与海南环境的互作在两种背景下提早抽穗2~3 d，与北京环境的互作则延迟抽穗2~3 d，是影响抽穗期的一个重要主效QTL。通过与以往相同亲本来源的7个不同定位群体在不同环境下定位结果的比较，鉴定出一些在不同遗传背景和环境下稳定表达的主效QTL，如QHd3、QHd8a、QPh3和QPh4，适宜用于水稻抽穗期和株高的分子标记改良。基于QTL定位结果，本文对如何通过分子标记辅助改良品种在不同环境下的抽穗期进行了深入探讨。

Genetic Background Effect on QTL Expression of Heading Date and Plant Height and Their Interaction with Environment in Reciprocal Introgression Lines of Rice

Expression of quantitative trait is affected by genetic background and environment. Genetic background effect on QTL mapping and QTL by environment interaction for heading date (HD) and plant height (PH) in Beijing and Hainan environments were dissected using a large set of reciprocal introgression lines (ILs) derived from a japonica variety “Lemont” and indica variety “Teqing”. The two sets of ILs showed transgressive segregation for the two traits. Total 16 and 17 main-effect QTLs were identified for HD and PH in the two environments, respectively. Among them, only five main-effect QTLs (QHd2, QHd8a, QPh3, QPh5,and QPh12) were detected under the two backgrounds, indicating expression of most main-effect QTLs are specific to genetic background. Three main-effect QTLs (QHd8a, QHd9, and QHd10b) by environment interactions for HD were significantly detected under the two backgrounds, of which that of QHd8a had earlier heading for 2–3 days in Hainan, but delayed heading for 2–3 days in Beijing. Therefore, QHd8a could be considered as an important main-effect QTL for HD. By comparison with the QTL mapping results previously identified in the seven different mapping populations derived from the same parents in different environments, some stably expressed main-effect QTLs including QHd3, QHd8a, QPh3,and QPh4 were identified under different backgrounds and environments, suggesting these QTLs could be used in marker-assisted breeding for HD and PH. On the basis of the mapping information, marker-assisted improvement of HD for a rice variety under different environments was deeply discussed.