2017 Volume 86 Issue 4 Pages 358-366
Easy-shattering habit of the rice plant increases head loss in the Japanese head-feeding combine harvester, while the non-shattering habit increases processing loss in the conventional combine harvester. Thus, the performance of combine harvesters depends on the grain-shattering trait of the rice plant. To evaluate the effects of the grain-shattering trait on various losses at combine harvesting, we developed pairs of near-isogenic lines (NILs) for shattering habit by the selfing method. The NILs were derived from a cross between japonica rice cultivars, namely, “Asahi” and “Setokogane”; “Asahi” has an easily shattering habit, while “Setokogane” has a hard-to-shatter habit. We developed eleven pairs of NILs. Alleles at qSH1 locus were found to be associated with either easily shattering or hard-to-shatter in the pairs of NILs. Grain-shattering habits of eleven hard-to-shatter lines were not significantly different from each other, but, those of some easily shattering lines were significantly different. This shows that the genetic background affected the grain-shattering degree in the lines with shattering. These data suggest that additional loci with minor effects on the grain-shattering habit may exist in the cross between “Asahi” and “Setokogane”. Additionally, the non-functional allele at qSH1 which involves the hard-to-shatter habit, may behave epistatic to other loci. Thus, the NILs would be used to conveniently evaluate the effects of the grain-shattering trait on various losses at combine harvesting and the genetic analysis of grain-shattering in japonica rice.
