Quantitative trait loci (QTL) were identified for heading date and plant height in rice ( Oryza sativa L.) using a recombinant inbred line population consisting of 241 lines. Totally 4 QTLs for heading date and 4 QTLs for plant height were detected in three years. The QTL with large effects located in the interval C1023-R1440 on chromosome 7 was simultaneously detected in three years for both traits. In order to distinguished the interval whether contained one QTL with pleiotropy effect or two close linked QTLs, a recombinant line RIL50, whose genetic background was high similar to Zhenshan 97 except the regions covered the major QTL from Minghui 63, was selected to cross with Zhenshan 97. A BC1F2 population from the cross, which could be regarded as near isogenic lines (NIL) with the targeted QTL (QTL-NIL), was used to collect heading date and plant height data. The frequency distribution of the two traits in the BC1F2 population was bimodal, and their segregation ratios were in accordance with the expected Mendelian inheritance ratios. Normally, the short plants flowered early in the population, the high plants with late heading date, but the relationships between the plant height and the heading date of 6 plants conflicted with the case. The above results clearly demonstrated that QTL could be treated as single Mendelian factor. Moreover, there are two close linked genes controlling the heading date and the plant height on chromosome 7, respectively.
邢永忠 徐才国 华金平 谈移芳 孙新立
摘要：利用241个重组自交系构成的群体,对水稻(Oryza sativa L.)株高和抽穗期进行基因定位。三年共定位到4个抽穗期的数量性状基因(QTLs)和4个株高QTLs,其中位于第7 染色体C1023-R1440区间的QTL 3年均可检测到,且效应大,同时影响株高和抽穗期。为了区分这个区间的QTL是一因多效还是紧密连锁的两个QTLs,从自交系群体里选取QTL区间来自明恢63,其他遗传背景与珍汕97高度相似的自交系RIL50,与珍汕97回交,获得含有363个单株的近等基因系BC1F2群体。考察株高和抽穗期,两个性状在群体里表现为双峰分布,它们的分离比符合期望的单基因孟德尔遗传分离比。BC1F2群体单株的株高和抽穗期基本表现为矮秆早抽穗,高秆迟抽穗,但是,6个单株表现相反的情况。以上结果证明,QTL能够作为孟德尔因子进行研究,在BC1F2群体里,株高和抽穗期是由单个基因控制的,第7染色体上是两个紧密连锁的基因分别控制株高和抽穗期。