Fine Mapping Of A Mutant Gene Lhd Controlling Reproductive Development In Rice

The genetics and molecular mechanism underlying plant reproductive development have become a heat topic in plant developmental biology. Mutants are good experimental materials. And the acquisition of and research on the mutants related to reproductive development played an important role in uncovering the function of and interactions between genes in the process of reproduction. Rice is one of the most important food crops in the world, providing heat resources for over one third of the whole population. The result of reproductive development directly determines grain quantity and quality in rice. So the research of genes for reproductive development has practical meanings. A mutant called leafy head (Ihd) was found in a double haploid (DH) population derived from a cross between a japonica variety Taiwan] ing and an indica rice variety Gui630. The Ihd mutant is shorter in height, has smaller leaves which appear to be clumpy, and produces many leafy branches with small leaves at the top of the stems during the time when the wild type begins to develop young panicles. So, Ihd mutant cannot enter the stage of reproductive development. A previous study has mapped the Ihd gene onto chromosome 10 with SSR markers, but the linked markers were found on one side of the target gene. In the present study, an F2 population was developed from a cross between the carrier of mutant gene Ihd and Minghui 77, an indica rice variety, to detect molecular markers more closely linked to Ihd. With the aid of RAPD and ISSR markers and by means of BSA mutant analysis, 198 out of 400 RAPD primers showed polymorphisms between Ihd and Minghui77. But only one marker OPG13 was discovered to be linked3with Ihd gene, located on the other side of the Ihd gene, with a genetic distance of 16.2cM.In addition, 9 out of 92 (about 9.7%) ISSR primers showed polymorphisms between mutant Ihd and Minghui77, but no marker was detected to be linked to Ihd gene.