Abstract:

In this study, the pathogen isolated from the infected alfalfa(Medicago sativa)leaves was cultured, purified and identified as Alternaria alternata. Twenty one alfalfa varieties were infected and for disease resistance evaluation in field and in vitro leaves, combined with laboratory hydroponic infestation sampling to measure phenylalanine ammonia-lyase (PAL) activity. Disease resistance of the 21 alfalfa varieties was compared comprehensively using the fuzzy subordinate function method. The results showed that the order of disease resistance of the 21 alfalfa varieties was:‘Instinct’ > ‘MT4015’ > ‘Beilin201’ > ‘Tango’ > ‘Vision’ > ‘Barcrown’ > ‘Magna995’ > ‘SK3010’ > ‘Dryland’ > ‘Spyder’ > MF4020 > ‘MagnaGrazeⅡ’ > ‘Magna801’ > ‘Magna601’ > ‘MagnumⅦ-Naiwang’ > ‘Victoria’ > ‘MagnumⅦ’ > ‘Zhao Dong’ > ‘Magnum-salt’ > ‘Zhungeer’ > ‘Xinjiang Daye’. The study not only provides scientific basis for fast screening of disease resistant materials and promotion of good varieties, but also refers for choosing alfalfa varieties resistant to leaf spot in practice.

Key words: Alternaria alternata, Alfalfa leaf spot, Alfafa varieties, Disease resistance evaluation

摘要：

本研究以田间病叶分离鉴定的交链格孢菌（Alternaria alternata）对紫花苜蓿（Medicago sativa）21个品种进行侵染，结合田间实验、室内离体叶片和水培枝条实验，利用模糊隶属函数法综合评价不同品种对苜蓿斑点病的抗性。结果表明，抗苜蓿斑点病强弱依次为‘英斯特’ > ‘MT4015’ > ‘北林201’ > ‘Tango’ > ‘威神’ > ‘皇冠’ > ‘巨能995’ > ‘SK3010’ > ‘Dryland’ > ‘斯贝德’ > MF‘4020’ > ‘巨能2’ > ‘巨能801’ > ‘巨能601’ > ‘巨能7-耐望’ > ‘维多利亚’ > ‘巨能7’ > ‘肇东’ > ‘耐盐之星’ > ‘准葛尔’ > ‘新疆大叶’，为抗病材料的快速筛选和优良品种的推广提供科学依据，也为生产中选择对苜蓿斑点病抗性强的苜蓿品种提供了参考。

关键词: 链格孢, 苜蓿斑点病, 苜蓿品种, 抗病性评价