Evaluation and screening of rice germplasm resources resistant to rice false smut

【Objective】In order to provide valuable rice materials for rice smut resistance breeding，the germplasm resources of rice varieties resistant to rice false smut were explored.【Method】212 rice materials from the International Rice Research Institute were evaluated at the booting stage by inoculating with Ustilaginoidea virens during the 2016-2020 period. All the materials were evaluated for resistance to rice false smut in 2016. Those with moderate or higher resistance was identified in 2017-2018 and further evaluated for resistance in 2019-2020.【Result】The results showed that the most of the 212 lines were susceptible，but 15 were resistant to the rice false smut pathogenin the experiment of inoculation with U. virens for five consecutive years. Among them，KHAO DAM::IRGC 23385-1，IR 77298-14-1-2::IRGC 117374-1， DUMAI::IRGC 25852-1，WARABEHATOMOCHI::IRGC 14779-1，EDOGAWA::IRGC 74468-1，IR 65482-17-511-5-7:: IRGC 117284-1，QUILA 64117::IRGC 117024-1 and VASSE NANAN::IRGC 56812-1 were highly resistant to rice false smut. In addition，the results showed that the resistance of different rice varieties to rice smut differed，and the resistance level of indica germplasm was higher than that of japonica. The resistance of rice germplasm resources with differing ripening times was different，that was，early-maturing varieties>medium-maturing varieties>late-maturing varieties. However，not all early-maturing rice had better resistance to the disease. The disease resistance of early-maturing varieties was reduced under sufficient selection pressure.【Conclusion】In this study，8 rice materials are selected with high resistance to rice false smut，which provides excellent material for use in breeding programs for enhanced resistance. In addition，the resistance level of indica rice germplasm is on the whole higher than that of japonica rice and early-maturing varie-ties> medium-maturing varieties>late-maturing varieties.