Induced Genetic Variability in Selected γ-Radiated Cotton Varieties during Second Year Ratooning Under Rain Fed Environment

The cotton is one of the most raw materials of the textile industry. At the same time, Pakistan is one of the most important cotton producing countries. Cotton has a wide variety of uses, especially in the textile industry. Cotton cultivars response to different doses of gamma radiation for branches plant-1, leaves plant-1,bolls plant-1, flowers plant-1, seed weight (g), cotton weight plant-1, intermodal length (cm), hundred seed weight (g) and plant height (cm) were studied in 2013. Three newly developed cotton varieties i.e Gomal-93, Bt-131 and Bt-CIM-602 previously (2012) irradiated @ 0, 10, 15, and 20 kR in Nuclear Institute for Food and Agriculture, Tarnab, Peshawar, Pakistan. The cotton varieties were sown in May, 2012 University of Science & Technology, Bannu. After harvesting cotton varieties were left in the field for 2013 production as ratoon crop. The experiment was laid out in randomized complete block design with split arrangement i.e. radiation treatment were kept in main plots and varieties in subplots. Radiation treatments significantly affected branches plant-1, Leaves plant-1, flowers plant-1, cotton weight plant-1, intermodal length (cm) and hundred seed weight (g) except bolls plant-1 and plant height (cm). Maximum branches plant-1 (24.3), flowers plant-1 (234.5), and heavy seed weight (7.98 g) were recorded in cotton varieties when irradiated at the rate of 15 Krad. While highest cotton weight plant-1 (34.4 g) were recorded at 10 Krad treated seeds. Highest flowers plant-1 (241.3), seed weight plant-1 (8.2 g), lengthy plants (4.81 ft) and maximum cotton weight plant-1 (33.9 g) were observed in Bt-131 variety. Bt-131 is recommended for general cultivation and production in Bannu.