Bunketsu-waito, One of the Tillering Dwarfs, is Controlled by a Single Recessive Gene in Rice (Oryza sativa L.)

Abstract

Bunketsu-waito, one of the tillering dwarfs, was reported to be controlled by triplicate genes, d3, d4 and d5. Although a segregation ratio fitting to 15: 1 for bunketsu-waito was observed in the F2s of the crosses between H-52 (bunketsu-waito) and genetic marker lines No.201 or H-61, the backcross of (H-52 × H-61) F1 × H-52 showed a segregation ratio of 1: 1 for normal vs. bunketsu-waito and the reciprocal backcross showed a decrease of the segregation ratio for bunketsu-waito from 1: 1. These results demonstrated that bunketsu-waito was controlled by a single recessive gene and suggested that the abnormal segregation of bunketsu-waito in the F2 of H-52 × H-61 was caused by a gametophyte gene linked to a gene for bunketsu-waito. Furthermore, the decrease of the segregation ratio of bunketsu-waito in the F2 of H-125 × Kasalath was also observed and was considered to be due to a gametophyte gene, based on the results of reciprocal backcrossing between H-125 and the F1 of H-125 × Kasalath. Thus, it was assumed that bunketsu-waito was controlled by a single recessive gene, and that the bunketsu-waito gene was mapped between RM 587 and RM 4608 on chromosome 6, based on linkage analysis using SSR markers.