甘蔗分离群体的黑穗病病情指数分析

摘要

在田间进行2组试验以分析甘蔗分离群体的甘蔗黑穗病病情指数.新植蔗和宿根蔗分别有72份和50份无性系参试.采用孢子悬浮液浸渍法对新植蔗进行接种,并收集新植蔗和宿根蔗自第1个黑穗病鞭子出现至发病停止期间的数据.对所收集到的新植蔗3个病情指数茎感染率(SI)、丛感染率(PI)和病害进展曲线下的面积(AUDPC)的数据进行正态分布检验.结果表明:AUDPC与标准正态分布曲线最吻合,其3个特征值正态度、偏度和峰度分别为0.949,0.018和-0.721;PI的吻合程度次之;SI为第3.以上结果的置信度大于97.7%.不论新植蔗还是宿根蔗,3个病情指数两两间以及各病情指数与持续发病期(SDD)间均呈显著正相关,在AUDPC与SI间的相关系数最大,新、宿分别为0.929和0.888.除潜伏侵染期(LP)与PI间的相关外,LP与AUDPC、SI和SDD间的负相关均达到显著水平,LP与SDD间的负相关系数最大,为0.521.相关分析结果暗示,在进行甘蔗抗黑穗病性评价时,利用包括病情指数和病害流行学参数在内的多个参数综合评价抗病性是必要的.%Two trials were conducted in field to analyze the infection index of smut caused by Ustilago scitaminea in sugarcane segregated population. Seventy-two individuals in plant cane and fifty individuals in first ratoon cane were inspected by means of artificial dip-inoculation in plant cane. Data of disease epidemic parameters and of infection index were collected from the appearance of the first smut whip to the end of disease development in two crops. The Normal distribution test of the data of three indexes ,i.e. stalk infection (SI), plant infection (PI) and area under disease progress curves (AUDPC) was made in plant cane. Results showed that the values of Normal, Skewness and Kurtosis for the index of AUDPC were 0.949, 0.018 and -0.721 respectively, indicating that the distribution of AUDPC index was closest to normal distribution, followed by the index of PI and SI. The credibility was more than 0.023 i.e. 97.7 %.Correlation analysis was conducted in plant cane and in ratoon cane. In plant cane or ratoon cane, significant positive correlations between every two of infection indexes of AUDPC, SI and PI and between every infection index and disease epidemic parameter of SDD were found. The maximum correlation coefficient was found between AUDPC and SI, the values were 0.929 in plant cane and 0.888 in ratoon cane. Except for latent infection period (LP) and PI, significant negative correlations were found between LP and parameters of AUDPC, SI, and sustained disease duration (SDD) in plant cane. For negative correlation, the maximum value of 0.521 was found between LP and SDD. Results of correlation analysis suggested that multiple parameters including infection indexes and epidemic parameters should be taken into account for identification of smut resistance.