Response of Cotton (Gossypium Hirsutum L.) Cultivars to Different Irrigation Regimes in Zero Tillage System

Water shortage is becoming a serious concern for all crops and particularly for cotton, which has been a major export contributor of Pakistan. In this scenario, drought-tolerant cotton cultivars with zero tillage could be the best option. This research aims to quantify the impact of limited water on lint yield and quality of cotton genotypes. An experiment was managed in a split plot, randomized complete block design, replicated thrice at the Agricultural Research Institute, Dera Ismail Khan. The experiment was conducted in 2016 using treatments irrigation intervals (10, 15, 20 and 25 days) and Bt cotton varieties (MNH-886, CRIS-342, and CRIS-134) as main- and sub-plots treatments, respectively. Total irrigation water used in irrigation treatments, 10, 15, 20, and 25 days intervals were 1125, 750, 560, and 450 mm, respectively. Each experimental unit was 10 × 3 m². Results showed that all the parameters under study had a significant response to the treatments irrigation intervals. Irrigation intervals of 10 days produced more sympodial branches (14) and higher plant height (131cm) as compared to other irrigation intervals. Higher bolls (19 / plant), boll weight (2.9 g), seed cotton (2424 kg ha^-1), ginning out turn (GOT, 37%), fiber length (28.1mm), fiber strength (29.5 g per tex) and micronaire value (3.5 μg per inch) were achieved from irrigation interval of 25 days. Interaction effects (irrigation x varieties) revealed that variety CRIS-134 in combination with 25 days irrigation interval conserved 60 % more water, produced 60.5% more bolls per plant, 21.1% higher GOT, 48.7% higher seed cotton yield, and 12.4% higher fiber length compared to all other combinations. Results indicate that CRIS-134 with 25 days irrigation interval in zero tillage system is more advantageous and adaptable in agro-ecological conditions of Dera Ismail Khan.