Effect of Planting Date on Tuber Yield and Early Blight Disease Severity in Six Potato Cultivars in Faridan, Isfahan

The effects of three planting dates with 15 days intervals, on the tuber yield and early blight disease severity in six potato cultivars were studied in Freidan, Isfahan province, Iran, for the two years 2011-2012. The results indicated that, the planting date had significant effects on yield and disease severity of potato. Maximum tuber yield was obtained in the first of June planting date, followed by the mid and end June planting dates (30.00, 23.62 and 20.07 tha-1, respectively. The cultivars Maradona and Agria with 31.80 and 31.71 tha-1 had the highest yield followed by Sonate and Marfona with 31.57 and Cosima and Diamante with 27.47 and 25.88 tha-1, respectively. In respect to the early blight, maximum disease severity was observed in the first planting date after flowering stage (2.76%), followed by the mid and late planting dates (2.27% and 2.05%), respectively). Potato cultivars had different disease severities. Cultivars Sante and Agria with 2.48 and 2.42%, had the highest, Diamond and Maradona with 2.08 and 2.09% the lowest and Marfona and Cosima with 2.34 and 2.35% had the intermediate disease severities, respeclively.