Genetic Analysis and Fine Mapping of Two Genes for Grain Shape and Weight in Rice

To identity genetic loci controlling grain weight, an elite indica rice variety, Baodali, with large grains was Identified and used in this study. Its derived F2, F3 and BC2F2 with another japonica dee variety Zhonghua 11 were used as mapping populations. Unkage analyses demonstrated that two genes controlling grain weight, designated as GW3 and GW6, were mapped to chromosome 3 and chromosome 6, respectively. Fine mapping delimited GW3 to a 122 kb physical distance between two sequence tagged site markers (WGW16 and WGW19) containing 16 open reading frames annotated by The Institute for Ganomic Research (http://www.tigr.org). GW6 was further mapped between two simple sequence repeat markers (RM7179 and RM3187). These results are useful for both marker assisted selection of grain weight, and for further cloning of GW genes, which will contribute to the dissection of the molecular mechanism underlying grain weight in rice.