225份水稻新品系对穗瘟的田间抗性初步评价

Preliminary evaluation of 225 new rice lines for panicle blast resistance under natural field conditions

【目的】对以抗瘟丝苗、新银占和BE621等3个稻瘟病抗性优良品种为抗源转育的225份水稻新品系进行田间穗瘟抗性鉴定,为水稻新品种(组合)稻瘟病抗性改良奠定基础。【方法】在广西岑溪市梨木镇对255份水稻新品系进行穗瘟田间自然诱发鉴定,以3个抗源亲本抗瘟丝苗、新银占和BE621为抗病对照,油占八号为感病对照。【结果】225份水稻新品系中有13份表现为1级抗性,约占5.8%;118份表现为3级抗性,达到中抗水平,约占52.4%;65份表现为5级抗性,表现为中感,约占28.9%;14份表现为7级感病,约占6.2%;15份表现为9级高感,约占6.7%。以抗瘟丝苗、新银占和BE621为抗源育成的品系中,抗性达到1～3级的品系分别约占59.6%、59.3%和51.4%。【结论】抗瘟丝苗和新银占的后代比BE621的后代更具抵抗稻瘟病危害的能力;该研究所获得的中高抗品系均能作为广西稻瘟病抗性育种材料,具有较好的应用前景。

[Objective]Two hundreds and twenty five new rice lines, bred using blast resistant parents, viz., Kangwensimiao, Xinyinzhan and BE 621, have been evaluated for panicle blast resistance which was a bais for registration of new rice varieties. [Method] Rice blast was inoculated on 225 new rice lines under natural field conditions in Limu County, Cenxi, Guangxi （China）, and the crop was investigated for the level of tolerance. The resistant parents Kangwensimiao, Xinyinzhan and BE621 were taken as resistant control, and Youzhan 8 as susceptible control variety. [Result] The tested 225 new rice lines differed greatly in level of resistance to panicle blast disease. Out of 225 lines, 13 lines （5.8%） showed grade 1 resistance （highly resistant）, 118 lines （52.4%） showed grade 3 resistance （moderately resistant）, 65 lines （28.9%） showed grade 5 resistance （moderately susceptible）, 14 lines （6.2%） showed grade 7 resistance （susceptible） and 15 lines （6.7%） showed grade 9 （high susceptible）. On comparing the offsprings with their resistant parents, it was found that grade 1-3 resistance was observed only in 59.6, 59.3 and 51.4% offspring of Kangwensimiao, Xinyinzhan and BE621, respectively. [Conclusion] The offsprings of Kangwensimiao and Xinyinzhan were found highly resistant to rice blast compared to those of BE621. The high and moderately resistant lines identified in this study can be used in breeding programs for breeding rice blast resistant ,4arieties.