Mapping of a Shattering Resistance Gene in a Mutant Line SR-5 Induced from an indica Rice Variety, Nan-jing 11

Abstract

A shattering resistance gene in a mutant line, SR-5, induced from an indica rice variety, Nan-jing11 was mapped on chromosome 3 based on QTL (Quantitative Trait Locus) analysis using RFLP markers, and it was designated as sh4. Seventy eight plants of the F₂ population derived from a cross between a javanica (tropical japonica) rice variety Dinalaga with shattering habit and SR-5 were investigated for the degree of shattering and marker genotypes by RFLP. The results of QTL analysis suggested that sh4 was located at the same position as that of an RFLP marker R250 on chromosome 3. In the F₂ population, the shattering degree showed a continuous distribution including transgressive segregation covering wider ranges of prone and resistance to shattering compared with parental variations. The variance explained (R²) at sh4 showed a lower value than the heritability (h²) of tbe shattering degree in the F₂ population. Based on the results of QTL analysis in the region on chromosome 1 where the shattering gene, sh2 and a single recessive shattering resistance gene in a mutant line SR-1, induced from an indica rice variety Nan-jing11, were localted, it was confirmed that these loci were not related to the segregation in the F₂ population. It was also suggested tbat in addition to sh4, other factors may control the trait.