Abstract
In order to clarify the inheritance for susceptibility in ‘Momiroman' and ‘Takanari', the high-yielding rice cultivars, to benzobicyclon, a 4-HPPD inhibiting rice herbicide, segregations of the susceptibility was analyzed in F2 generations of reciprocal crosses between the two cultivars and ‘Nipponbare'. The two cultivars, ‘Momiroman' and ‘Takanari' were clearly diagnosed susceptible and ‘Nipponbare' was diagnosed tolerant to the herbicide by double dosage treatment of a commercial one-shot herbicide, 1kg granule containing pyrazosulfuron-ethyl, fentrazamide and benzobicyclon, one day after transplanting of the two-leaf stage rice seedlings, 1kg granule of pyrazosulfuron-ethyl and fentrazamide combination. The segregations of the susceptibility in F2 generation obtained by the herbicide treatment were analyzed using chi-square test. The result revealed that the tolerant/susceptible segregations were fitted a 3:1 ratio. It is suggested that a susceptible trait of the two high-yielding rice cultivars to benzobicyclon is dominated by a recessive oligogene in nuclear, and is no evidence of cytoplasmic inferitance.
