Evaluation of some cotton genotypes for resistance to Verticillium dahliae Kleb. under field conditions

Abstract

Verticillium Wilt caused by soil-borne pathogenic fungi is one of the most significant diseases affecting the yield of cotton, and is almost uncurable with chemical agents. For this reason, it will be inevitable to cultivate resistant varieties. In this direction, this study was carried out to determine the response of cotton varieties and inbred lines obtained from cotton breeding projects of the GAP International Agricultural Research and Training Center (GAPUTAEM) in Diyarbakır, Türkiye. The trial was conducted in a randomized complete block design with four replications during the 2016 and 2017 cotton growing seasons. In the study, 12 advanced inbred lines (8, 20, 30, 34, 38, 57, 58, 63, 64, 8/4, 5/7, and 8/1) and 3 control varieties [Stoneville 468, Carmen (tolerant control), and Çukurova-1518 (sensitive-control)] were tested for the response to Verticillium wilt under naturally infected field conditions.
 Disease severity was determined in the leaf at 5-10% and 50-60% of the boll opening stages and in the stem section after harvest. Additionally, some yield parameters and fiber quality properties were investigated in the study. The results indicated that there were significant differences among genotypes for most of the investigated characteristics.
 It was determined that with regard to foliar disease index (FDI) at 5-10% and 50-60% boll opening stages and disease index of stem cross-section (SDI) the most tolerant genotype was inbred line 38, while the most sensitive variety was Çukurova-1518. To conclude, the inbred lines 30, 57, 38, and 20 were recommended because of their low disease index value and high yield capacity.