棉花抗黄萎病鉴定与评价标准的商榷

【目的】通过系统研究黄萎病抗病鉴定的关键技术和评价标准,解决现有棉花品种黄萎病抗性评价标准中存在的问题,建立新的田间棉花黄萎病分级标准和评价标准。【方法】以14个2014年国家主推棉花品种为试验材料,从接种量、可靠样本量、病情分级和评价方法 4个方面系统研究黄萎病抗性鉴定的关键技术和评价标准。【结果】确定了小区接种和行沟接种的最佳接菌量分别为60 g·m-2和10 g·m-1,小区调查最低样本量为50株;制定了新的分级标准为0级(0%)、1级(1%~33%)、2级(34%~66%)、3级(67%~99%)和4级(100%)。连续2年利用相对病程发病面积和发病高峰期的相对病情指数2种评价方法判定品种抗病性,前者作为抗病性评价的依据更为科学可靠,一致率达到100%。【结论】本试验为完善抗病鉴定技术操作规程,规范抗性评价方法,促进棉花抗病品种的选育、审定和推广提供了科学依据。

Development of an Improved Standard for Identifying and Evaluating Verticillium Wilt Resistance in Cotton

Objective] The purpose of this investigation was to systematically study the standard techniques used to identify and evaluate Verticillium wilt resistance in cotton to solve the traditional methods or develop a new one. Method] Fourteen nationally recommended cotton varieties in 2014 were used to systematically study the importance of inoculum concentration, sample number, disease level, and evaluation method. We also used the relative area under the disease progress curve and the related disease index at the disease peak to evaluate Verticillium wilt resistance in cotton in two consecutive years. Results] The ideal concentrations for plot and column inoculations were 60 g·m^-2 and 10 g·m^-1 based on the real-time monitoring of the disease index of susceptible variety (Jimian 11) plants. To improve the reliability of the data, the minimum number of investigated plants was set as 50 according to the divergence rate analysis. The new disease grading standard related to cotton yield was based on the foliar disease rate and included the following levels: 0 level (0%), first level (1%-33%), second level (34%-66%), third level (67%-99%), and fourth level (100%). And disease resistance evaluation results in two consecutive years showed applying the relative area under the disease progress curve produced 100% consistent results between years. Conclusion] The present study provides potentially useful data for improving the techniques used to evaluate cotton variety disease resistance, and may stimulate the breeding, authorization and promotion of new cotton varieties.