小麦单株产量与株高的QTL分析

 【目的】在QTL水平上揭示株高与产量的遗传关系及株高对产量的影响，为小麦高产育种株高的选择提供参考依据。【方法】利用分别包含229和485个家系的2个关联重组自交系群体（recombinant inbred lines，RIL）潍麦8号/烟农19（WY）和潍麦8号/济麦20（WJ），绘制2个较高密度遗传连锁图谱。在3个环境下对单株产量和株高性状进行测量评价及非条件和条件QTL分析，研究株高与产量QTL的相互关系及排除株高影响后单株产量QTL效应的变化，探讨群体大小对QTL定位精度和准确性的影响。【结果】在WY群体中检测到5个单株产量QTL和15个株高QTL，其中，8个QTL解释大于10%的表型变异，3个为一因多效QTL；条件QTL分析表明，3个单株产量QTL与株高QTL无关，2个单株产量QTL的效应完全或部分由株高QTL所贡献，1个单株产量QTL的效应被株高QTL抑制。在WJ群体中检测到7个单株产量QTL和11个株高QTL，其中1个主效株高QTL加性效应值为8.82 cm，可解释20.68%的表型变异；条件QTL分析表明，5个单株产量QTL与株高QTL无关，2个单株产量QTL的效应完全由株高QTL所贡献。大群体WJ检测到的QTL效应值比小群体WY小，但LOD值高。【结论】株高与产量的关系是多重因素共同作用的结果，包括一因多效或紧密连锁、株高QTL对产量QTL表达的贡献与抑制、环境效应以及与其它性状的互作等。不同遗传背景、不同生态环境下株高对产量的贡献是各个因素相协调的结果，高产育种中对株高的选择在不同背景下应该有所区别；与小群体相比，大群体检测QTL的精度和准确性更高。

QTL Analysis on Grain Yield per Plant and Plant Height in Wheat

【Objective】 The objective of this study is to reveal the genetic relationship between grain yield (GY) and plant height (PH) and the influence of PH on GY at the QTL level, and provide references for the selection of PH in wheat high yield breeding programs.【Method】Two high density genetic linkage maps were constructed using two associated recombinant inbred lines (RIL) derived from crosses of Weimai8/Yannong19 (hereafter WY) and Weimai8/Jimai20 (hereafter WJ), consisting of 229 and 485 lines, respectively. Both GY and PH of the three parents and the RIL populations were measured in 2009 and 2010 in Tai’an and Zaozhuang. Unconditional and conditional QTL analyse were conducted to detect the genetic relationship between GY and PH, and the QTL effect without the influence of PH. In addition, the effect of population size on the accuracy of QTL detection was discussed. 【Result】In the WY population, 5 and 15 QTLs were detected for GY and PH, respectively, of which totally 8 QTLs explained >10% phenotypic variation (PVE), 3 QTLs were pleiotropy which determined both GY and PH. For GY conditioned on PH, 3 QTLs affecting GY were detected independent of PH, two were totally or partial contributed to PH, and one completely suppressed by PH. In WJ, 7 and 11 QTLs were detected for GY and PH, respectively. One QTL was a major gene affecting PH with additive effect of 8.82 cm, explaining 20.68% of PVE. Conditioned GY on PH, 5 QTLs were identified independent of PH and two were totally due to PH. The QTL effect of the large population WJ was smaller than that of WY, while the LOD scores were higher.【Conclusion】The genetic relationship between GY and PH is contributed and coordinated by various factors, including closely linked or pleiotropy, the contribution or suppression of PH to GY, environmental factors and the interactions between traits, etc. The selection of PH in high yield breeding programs should refer to different genetic backgrounds and ecological environments. A population of large size can detect QTLs more accurate than small ones in QTL mapping.