利用254个Lemont导入到特青背景的高代回交导入系定位了灌溉（对照）与自然降雨（干旱胁迫）环境下影响单株籽粒产量及其穗部相关性状的QTL。在两种环境下共检测到32个影响单株粒籽产量、千粒重和每穗实粒数的主效QTL，根据不同环境下表达的情况将其分成3类，第1类10个QTL，在两种环境下均被检测到；第2类14个QTL，只在对照条件下检测到；第3类8个QTL，受干旱胁迫诱导，只在胁迫条件下被检测到。此外还检测到9个影响胁迫与对照条件下性状差值的QTL。认为在两种条件下均检测到的相对稳定的3个QTL（QGn11b、QGn12和QGn11b）及影响两种条件下性状差值（即性状稳定性）的9个QTL可能对耐旱性有直接贡献。在所有12个耐旱QTL中，除在QGn5和QGy1的Lemont等位基因减小性状差值（即增强耐旱性）外，其余位点上增强耐旱性的等位基因均来自特青。另外通过与源自相同亲本的不同定位群体在不同环境下定位结果的比较，鉴别出一些受遗传背景和环境影响较小的QTL如QGn3b、QGw1、QGw5、QGy1、QGy5、QGy8和QGy10。对应用QTL定位结果进行标记辅助选择培育耐旱品种进行了探讨。
In rice breeding community, drought tolerance (DT) is becoming one of the most important target traits for variety improvement under ever-increasing severe drought situation all over the world. Yield is the most important target focused by breeders, so identification of favorable alleles related to yield and yield components for introgression into rice varieties that suit the specific environments is an efficient practice in plant MAS breeding. In the present study, the QTL conditioning the grain yield per plant (GY) and its component traits including 1000-grain weight (GW) and filled grain number per panicle (GN) in irrigation(control) and rainfed (drought stress) fields were investigated using 254 advanced backcrossing introgression lines (IL) of Lemont with Teqing genetic background and the two parents. Total of 32 main-effect QTLs for GY, GW, and GN were identified in the two conditions which can be grouped into three types based on their behaviors. TypeⅠincluded 10 QTLs which were detected both in the two conditions, type Ⅱ consisted of 14 QTLs which were mapped only in control condition, and type Ⅲ comprised 8 QTLs which were induced by drought and detected only under stress. In addition, nine QTLs affecting trait differences between stress and control were identified (QGn5, QGn6,QGn11a, QGw2, QGw8, QGw11a, QGw11b, QGy1, and QGy11). There were three QTLs (QGn11b, QGn12, and QGn11b) which expressed both in the two conditions with same direction and magnitude of gene effect. Therefore the three GN-QTLs and nine QTLs affecting trait differences were considered to directly contribute to drought tolerance (DT). Teqing alleles at the 12 DT-QTLs except QGn5 and QGy1 were associated with DT. As compared with the results from different mapping populations derived from the same parent, Lemont and Teqing, in different environments, seven QTLs including QGn3b, QGw1, QGw5, QGy1, QGy5, QGy8, and QGy10 which stably expressed across different genetic backgrounds and environments were identified. The strategy of applying QTL mapping results in rice improvement for DT by marker-assisted selection was discussed.
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