Screening of cultivars and lines for resistance to rice-ear bugs in rice (Oryza sativa L.)

To identify the resistance to rice-ear bugs, 503 rice cultivars were screened by three methods: the field screening method, group screening method and individual screening method. In the field screening method, the rate of pecky rice incidence on each cultivar was investigated in the paddy field. In the group screening method, relative resistance was investigated by inoculation of rice-ear bugs to two or more rice cultivars in mosquito nets. In the individual screening method, each cultivar was infested by rice-ear bugs in mosquito nets. On the early screening stage, the field screening method and group screening method were used for the rough selection of resistant cultivars. Then, the highly resistant cultivars were selected by the individual screening method. Leptocorisa chinensis and Nezara viridula were used as rice-ear bugs in this study. As a result, “GP242”, “TI-11-8”, “Milyang 44” and “CRR-99-95W” were demonstrated to have high resistance to Leiptocorisa chinensis. “Milyang 44” and “CRR-99-95W” also exhibited resistance to Nezara viridula. These two cultivars are expected to be used for breeding the pecky rice resistant cultivars.