Genetic Analysis and Gene Mapping of Short Root Mutant Rice ksr1

A short root mutant ksr1 with the Kasalath background was isolated from an EMS-mutagenized population in rice. The root length of 6-day-old ksr1 seedlings was only about 20% of the wild type. Genetic analysis indicated that the short root phenotype of ksr1 was controlled by a recessive mutation in a single nuclear-encoded gene. To map the ksr1 mutation, an F2 population was generated by crossing the ksr1 mutant with Nipponbare. The KSR1 locus was linked to the SSR marker RM1223 on rice chromosome 4. Eight new SSR markers and two InDel markers were developed around this marker. KSR1 gene was further mapped to a 155 kb region, flanked by the InDel marker 4-24725K and the SSR marker RM17182.