Document Type : Agricultural Entomology
Authors
1
Plant Protection Research Department, Golestan Agricultural and Natural Resources Research Center, Agricultural Research, Education and Extension Organization, Gorgan, Iran.
2
Associate Professor ofAgricultural and Horticultural Sciences Research Department, Golestan Agricultural and Natural Resources Research Center, Agricultural Research, Education and Extension Organization (AREEO), Gorgan, Iran.
3
Master's degree in Agricultural Entomology, Department of Horticulture and Plant Medicine, Faculty of Agriculture, Shahrood University of Technology, Shahrood, Iran
4
Master's degree in Forest Management, Faculty of Forest Sciences, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.
5
export of Plant Protection Research Department, Golestan Agricultural and Natural Resources Research Center, Agricultural Research, Education and Extension Organization (AREEO), Gorgan, Iran.
Abstract
Phytophthora nicotianae is one of the important pathogens in tobacco by causing tobacco black shank. Applying genetic resources to improve resistant varieties is the most effective method to control this disease. In order to determine the resistance of genotypes to this disease, 26 tobacco genotypes, including 16 F1 hybrids, 8 parents, and 2 controls, were evaluated with three replications in greenhouse and field conditions. Inoculation of the plants were done by placing the disease-causing fungus discs at the base of each plant. The traits studied in greenhouse conditions included disease severity, Latent period, and in field, were disease percentage, disease index, and AUDPC. Cluster analysis using Ward's method was used to group the cultivars. Variance analysis indicated that there were statistically significant difference at the 1% level between the genotypes in the greenhouse and the field. Genotypes 18 (Coker 371G) and 8 (Coker 371 G × Coker 347), were selected as the most resistant cultivars in the greenhouse and field. Based on the dendrogram of cluster analysis, the cultivars were classified into three groups: resistant, semi-resistant, and susceptible in the greenhouse, and into four groups: resistant, semi-resistant, semi-susceptible, and susceptible in the field.
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