云南主栽核桃品种对Alternaria alternata叶枯病的抗病性评价

Evaluation of the resistance of main walnut varieties in Yunnan province to Alternaria alternata

为了解云南地区不同核桃品种对叶枯病的抗性,从而为核桃抗病品种选育和叶枯病的防治提供依据,试验采用田间调查和离体叶片接种法获得病斑面积和病情指数,采用聚类分析的方法对田间调查和离体接种的病斑面积进行聚类分析,并结合病害分级标准,综合评价云南主栽37个核桃品种对Alternaria alternata的抗病性。结果表明:‘大泡核桃1’叶片上未出现病斑,‘小圆果’病斑面积最小,为5.05 mm^2,而‘圆菠萝2’病斑面积最大,达到887.68 mm^2;采用Ward最小偏差平方和法和欧式距离进行聚类分析,其聚类效果与接种结果和田间调查结果的吻合度最好。通过田间调查和离体接种综合评价,将37个核桃品种分为13个抗病品种、15个中抗品种、7个中感品种和2个感病品种。

In order to provide the basis for breeding of resistant varieties and controlling of leaf blight disease of walnut.In the experiments,the disease spot area and disease index were obtained by field investigation and in vitro evaluation inoculum method,then cluster analysis was used to analyze the disease spot area data of field investigation and in vitro evaluation.Combined with the disease classification standard,the disease resistance of 37 walnut varieties planted in Yunnan to Alternaria alternata was comprehensively evaluated.The results showed that the lesion did not appear on the leaves of‘Hickory walnut 1’,and‘Xiaoyuanguo walnut’showed the minimum lesion area of 5.05 mm^2,while the‘Yuanboluo walnut 2’had the largest lesion area of 887.68 mm^2.Cluster analysis by Ward least deviation square sum method and Euclidean distance indicated that the results of clustering were in good agreement with the results of inoculation and field investigation.By component analysis of field investigation and in vitro leaf-inoculation,the 37 walnut varieties can be divided into 13 resistant varieties,15 middle resistant varieties,7 middle susceptible varieties,and 2 susceptible varieties.