Abstract
With the inclusion of BT cotton in the existing cotton-wheat cropping system of South Punjab, Pakistan; farmers are
interested to sow early BT cotton to obtain its full production potential. There is a problem of sub and supra optimum
temperature due to early and late sowing of BT cotton. Little efforts have been done to optimize the best sowing date of BT
cotton in cotton-wheat cropping system. In this study, popular BT cotton cultivar MNH-886 was sown from February 14 till
May 15, with two weeks interval, in soil filled earthen pots kept under natural conditions. Early sown (planted on February
14 and March 01) crop took more days to start emergence, complete 50% emergence and mean emergence time, and had
minimum plant emergence. However, late sown (30
th April and 15
th May) took less time to germinate, with better and
uniform seedling establishment. Although early planted crop took more days to start emergence, squaring, flowering, boll
formation and boll opening but growing degree days to start emergence, squaring, flowering, boll formation and boll opening
were high in late sown crop. However, BT cotton sown on 16
th March yielded better than all other sowing dates owing to
increase in yield related traits like number of sympodial branches, bolls per plant and boll weight; while crop sown on 15
th
May didn’t perform well. Likewise sowing of BT cotton on 16
th March had better fiber quality in terms of ginning out turn, fiber length, strength, fineness and uniformity. There was a positive correlation of phenological events like days to start
squaring, flowering, boll formation and boll opening with seed cotton and lint yield of BT cotton; and cotton yield and boll
weight were also positively linked with fiber quality traits. In conclusion, planting of BT cotton on 16
th March is the best
option to harvest higher seed cotton and lint yield of better quality fiber under arid to semi–arid conditions of South Punjab, Pakistan.
