R. Mineva1*, V. Yankova2, N. Valchev1 1Department of Plant Production, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria 2Maritsa Vegetable Crops Research Institute, 32 Brezovsko shose Str., 4003 Plovdiv, Bulgaria (Manuscript received 1 June 2021; accepted for pub