云南蚕区家蚕品种资源对家蚕核型多角体病毒的抗性评价分析

Resistance of silkworm variety resources from Yunnan sericultural areas to Bombyx mori nucleopolyhedrovirus(BmNPV)

【目的】全面掌握云南蚕区家蚕品种资源的抗家蚕核型多角体病毒(Bm NPV)能力,为挖掘具有特色的家蚕抗病材料及培育适应当地的抗病品种提供参考。【方法】采用三龄起蚕经口添食相同浓度病毒、逐日调查存活率的方法,对200个家蚕品种(品系)进行Bm NPV抗性评价和筛选;并通过接种后每日存活数、各发育时期存活率等指标分析云南蚕区家蚕品种资源对Bm NPV的抗性水平、发病死亡规律、不同抗性品种的发病死亡时期及同一品种不同品系间抗性差异。【结果】云南蚕区家蚕品种资源中抗Bm NPV的品种有731、795、854B、872A、966B、B黄肉色茧、P50、山河B、选二甲白和竹印,感病品种包括955、242A、242B、963B、DW3、锦秀A、锦秀B、日、野乙和云夏A油。各抗病品种和感病品种首次出现死亡差异的时间截点分别是接种后96和48 h,二者相差48 h;部分抗病品种在秋季对Bm NPV的抗性水平低于春季;同一家蚕品种A系和B系的抗病性差异不显著(P>0.05)。【结论】云南蚕区家蚕品种资源中大多数品种的抗Bm NPV能力属于中等水平,其中P50为Bm NPV抗性最强品种。对未知品种进行抗Bm NPV测定时,可选择接种后168 h作为抗性评价的时间截点。

【Objective】The present study investigated resistance of silkworm variety resources from Yunnan sericultural areas to Bombyx mori nucleopolyhedrovirus（BmNPV） in order to search for disease-resistant materials and breed resistant varieties adapting to local conditions. 【Method】BmNPV of the same concentration were added into silkworm feed for the 3rd instar larva. BmNPV disease resistance of 200 silkworm varieties（strains） was evaluated. Based on indexes like survival number per day and survival rate at each growth period, BmNPV resistance level of the silkworm varieties in Yunnan sericultural areas, morbidity and death regularity, death time of different resistant varieties, and resistance comparison between different strains of the same varieties were analyzed. 【Result】Mediately resistant varieties in Yunnan sericultural areas included 731, 795, 854B, 872A, 966B, B Huangrousejian, P50, Shanhe B, Xuanerjiabai and Zhuyin; susceptible varieties were 955, 242A, 242B, 963B, DW3, Jinxiu A, Jinxiu B, Ri, Yeyi and Yunxia A You. The difference in silkworm death occured at 96 h post inoculation for resistant varieties while 48 h post inoculation for susceptible varieties. Disease-resistant varieties was 48 h later than susceptible varieties in the emergence of death. For some disease-resistant varieties, the resistance to BmNPV in autumn was weaker than in sprig. There was no significant difference in resistance between A starin and B strain belonging to the same varieties（P〉0.05）. 【Conclusion】Most varieties of the silkworm resources in Yunnan are mediately resistant to BmNPV. P50 has the strongest disease resistance. When evaluating resistance to BmNPV of unknown varieties, 168 h post inoculation can be consider as a key time point.