Development of Verticillium dahliae in Cotton Plants Grown in Cukurova and Reaction of Some Cultivars to Wilt
Feb 15, 2019
Seven cotton cultivars were inoculated with Verticillium dahliae Kleb. using a spore suspension of 2.5x106 conidia/ml by the stem puncture technique. Infection development of symptoms on plants inoculated with T-1 and SS-4 strains were investigated until the 25th day after inoculation. Strain T-1 reached 15 cm above the inoculation point in 7 days in all cultivars tested except Cukurova 1518, while strain SS-4 moved the same distance in all cultivars except Sayar314 in the same period. On 21st day after inoculation, strain T-1 was isolated 30 cm away from inoculation point in all cultivars except Sayar 314 and DPL50 but strain SS-4 was isolated from 17 cm away in all cultivars except Sayar 314. The results showed that strain T-1 progressed faster than isolate SS-4 in the first 21 days. However, by the 25th day, infection development for both isolates was about the same with 30 cm movement in all cultivars. Disease severity was recorded as foliar symptoms and vascular discoloration in both greenhouse and field conditions. Cultivars Deltapine 15/21, Maras 92, Sayar 314 and Ersan 92 were highly susceptible to T-1 in the greenhouse while cultivar Deltapine 15/21 was highly susceptible to SS-4. Acala cultivars were moderately resistant to SS-4. Cukurova 1518, a standard cultivar, showed little resistance to SS-4. The G. barbadense cultivars Giza 45, Giza 75 and Askabat were resistant to T-1 in the field. Amongst G. hirsutum cultivars, Acala was moderately resistant, while all other cultivars were susceptible to T-1. All cultivars except DPL15/21, Cukurova 1518 and Sayar 314 were highly or moderately resistant to SS-4.