Mapping and isolation of quantitative trait loci controlling plant height and heading date in rice

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 QTIs 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.