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Mepiquat chloride (MC) is a plant growth regulator used to manage the rampant vegetative growth of cotton. A two-year field experiment was conducted at the Postgraduate Agricultural Research Station, University of Agriculture, Faisalabad, Pakistan, during 2017 and 2018 to investigate the influence of MC applied at different times on phenology, morphology, lint yield and quality of cotton cultivated using different sowing techniques. MC was applied 50 days after sowing (DAS), 60 DAS and 70 DAS to cotton planted in flat fields (flat sowing), ridges (ridge sowing) and beds (bed sowing). The interactive effect of MC application time and sowing technique did not influence crop phenology, morphology, and lint yield and quality. It was revealed that the crop planted on beds took fewer days to flower (10%) as compared to that on the flat field, and the bed-sown crop produced a higher number of opened bolls (60%) and was characterized by a higher boll weight (32%) and seed cotton yield (50%) in comparison to the flat-sown crop. A late application of MC (at 70 DAS) caused a significant reduction in the time to flowering (8%), with a simultaneous increase in the number of opened bolls (60%), boll weight (32%), ginning out turn (8%) and lint yield (27%) as compared to MC application at 50 DAS. In terms of lint quality, cotton planted on beds had better fiber uniformity (8%) compared to that on the flat field, while MC applied at 70 DAS produced better fiber fineness by 27% in comparison to MC applied earlier. Overall, cotton planting on beds and MC application at 70 DAS may help improve cotton yield and fiber quality and may help in the mechanical picking of cotton. [ABSTRACT FROM AUTHOR]

Heat stress at reproductive stages of cotton is a leading encumbrance to accomplish yield potential. An experiment was conducted to alleviate adversities of terminal heat stress on cotton. Experiment was conducted at University of Agriculture Faisalabad, Pakistan during 2013 and repeated in 2014 using Randomized Complete Block Design (RCBD) with split arrangement. Treatments were comprised of heat stress in main plots, viz., H0 = no heat imposition, H1 = heat imposition at squaring, and H2 = heat imposition at flowering. Selenium was foliar applied in split plot, viz., Se0 = 0, Se50 = 50, Se100 = 100, and Se150 = 150 mg L−1. Cell membrane thermostability, soluble proteins, and total phenolics were reduced significantly under heat stress leading to reduced cotton yield and related components. Maximum membrane thermostability, total phenolics, soluble proteins, opened bolls, boll weight, sympodial branches, and seed cotton yield were recorded with the application 150 mg Se L−1. [ABSTRACT FROM AUTHOR]