【摘要】 种质资源筛选是抗病育种的前提和基础。以已知抗病水平的5份鉴别品种为对照,对水稻5个类群和1个混合类群的299份品种进行了温室苗期纹枯病抗性鉴定,筛选抗纹枯病水稻新种质。在"雾室/mist-chamber"环境下以改进的带菌木质短棒为接种物、以基于"叶枕高"的"0~9"级病级指标为标准,可有效区分对照品种间的抗病水平。299份品种中未发现免疫和高抗品种,中抗以上品种比例仅为36.5%,多数品种为中感至高感水平。就水稻不同类群而言,AUS类群中中抗以上品种的分布频率最高,超过60%;其次为ARO类群,为54.6%;分布频率最低的为TRJ类群,仅为22.7%。结合各品种苗高及与抗病对照YSBR1间的病级差异,从299份品种中筛选到7份抗病新种质,其中1份的抗性显著高于YSBR1,接近高抗水平。本研究为水稻抗纹枯病遗传育种提供了新的抗源,同时为选择合适的类群间品种杂交以培育抗纹枯病新品种提供了理论依据。更多还原

【Abstract】 Screening rice germplasm resources w ith resistance to sheath blight( SB) disease,caused by Rhizoctonia solani,is the prerequisite for rice breeding against this disease. In the present study,the seedling resistance of 299 rice accessions from five different sub-populations and one mixed population to SB disease w as evaluated by artificial inoculation in green house. Five varieties w ith know n SB resistance levels w ere included as controls to determine the resistant levels of new germplasms. The resistances of the five controls could be effectively distinguished to different resistant levels by using the "mist-chamber"method w ith the improved inoculum and the "0-9"rating scores that w ere calculated based on the height of the tallest leaf sheath. No rice variety w as found to be immune and high resistant to R. solani,and only 36. 5% of the tested varieties show ed resistant andmoderate resistant to SB disease. For different rice sub-populations,the AUS population had the highest ratio( more than 60%) of varieties with resistant and moderate resistant levels,then followed by ARO population w ith 54. 6%; the TRJ population had the low est ratio( only 22. 7%) of resistant varieties. Based on the difference betw een YSBR1,a w idely used SB-resistant control variety,and the tested varieties on the seedling height and SB scores,seven varieties among the 299 accessions w ere believed reaching resistant level to SB,and the variety Bico Branco show ed significantly stronger resistance to SB than that of YSBR1. Results of the study w ill not only provide the new resistant germplasms for rice breeding against SB disease,but also guide breeders to select appropriate sub-population in breeding program for developing SB-resistant rice varieties.更多还原