بررسي مقاومت ارقام مختلف كاهو نسبت به بيماري پژمردگي فوزاريومي

A Study of the Resistance of Lettuce Cultivars to Fusarium Wilt

Fusarium wilt of lettuce is an important disease of lettuce in the areas of Varamin, Shahre-Ray and Karaj. Considering the disease importance, glasshouse as well as field experiments were conducted to evaluate resistance or susceptibility of 15 lettuce cultivars, namely Great lakes 659, Summer Bibb. Bas Salata, Marul, All Year, Green Mignonette, Lolla Rosa, Grand Rapids, Ice berg and 6 Iranian native cultivars (Siahe Souri, Siahe Mashad, Karaj, Cefid Shaher- Ray, Maragheh and Dezful) to Fusarium oxysporum f. sp. Lactucum. Seeds were planted in infested soil with a mixture of four isolates of pathogen of the highest pathogen city potential. The randomized complete block designs with three and four replicates were employed for glasshouse and field experiments respectively. The results of glasshouse test indicated that the percentage of dry weight of roots, dry and fresh weight of shoots and percentage of non-diseased plants in cvs. Green Mignonette, Dezful and Maragheh were greater than those of other cultivars (P<0.01). The results of field experiment also showed that these three cultivars were the most resistant while All Years, Great lakes 659, and Summer Bibb were the most susceptible cultivars (P<0.01). There was a positive and significant correlation observed between the results of field and glasshouse experiments (r=0.74).