Effects of topping at different times on yield and fibre quality in cotton

This study was conducted in the Research Fields of Faculty of Agriculture, Dicle University in 2012 in order to determine the effects of topping at different stages of growth on yield and fibre quality in cottons grown in Diyarbakır conditions. In the study, cotton varieties of Primera, Deltapine 499, Stonville 453 and Berke (Gossypium hirsutum L.) were used as material. Trial was established using the pattern of Divided Parcels in Randomly Selected Blocks with 3 replications. Application times (control, 100, 115, 130 and 145 days after sowing) constituted the main parcels; cotton varieties (Berke, STV 453, DP 499, Primera) the sub-parcels. It was determined in the study that topping done 100 and 115 days after sowing date increased the seed cotton yield, seed cotton weight per boll, gin output, and fibre length; decreased the plant height and number of non-open bolls; had statistically no significant effect on characteristics such as 100 seed weight and fibre fineness, short fibre index, fibre elongation, spinning consistancy index, fibre uniformity.