ارزیابی واکنش ژنوتیپ‎های گردو منتخب استان لرستان به بیماری آنتراکنوز

Anthracnose is the most important fungal disease of walnut that is prevalent in all of the walnut growing areas of the world including Iran. The causal agent of disease (Marssoniella juglandis) causes economic losses on black walnut. To control walnut anthracnose, methods such as collecting and destroying plant debris and chemical control are used. In recent years use of resistant cultivars to manage of disease has been proposed because walnut trees especially native cultivars of Iran, are very tall and conventional spraying is very difficult, sometimes impossible. During the April to July of 2021 samples of infected leaves were collected from walnut orchards in Aleshtar region (Lorestan province) and transferred to the laboratory to isolate fungus and preparation of inoculum. Then to evaluate the reaction of 10 walnut genotypes to anthracnose, an experiment was conducted based on randomized completely design with four replications under greenhouse conditions. Walnut seedlings were inoculated with spore suspension 2 × 105 spores ml−1 and maintained in controlled environmental conditions (temperature 20-22 ° C, humidity > 95% and followed by 12h photoperiod). Traits such as number of infected leaves, number of infected spots, percentage of infected leaf area and the presence or absence of acervulus were used as criteria to evaluate the reaction of walnut genotypes. Analysis of variance showed significant difference between genotypes in all studied traits (P<0.001). None of the genotypes was resistant to the disease, although there were differences between them in studied traits. Infected leaf area, percentage of infected leaf area, number of spots and acervulus showed the greatest effect on the reaction of genotypes to the disease. Minimum and maximum infection was recorded in Pedro (%15 infection) and Fernor (%35 infection) genotypes, respectively.