Characterization of water-deficit tolerance in Upland cotton (Gossypiumhirsutum L.) assessing morphological, biochemical, molecular and yield attributes

Upland cotton (Gossypiumhirsutum L.) is an important crop in the world due to its natural fiber production. As a result of climate change, its production is affected due to frequent occurrence of water-deficit conditions during its growth period. Five cotton varieties, namely FH-114, FH-142, FH-152, CIM-473 and CIM-496 were evaluated under limited irrigation conditions to characterize water-deficit tolerance. The data were recorded for plant height, content of biochemical parameters (carotenoid, chlorophyll, wax, proline) and seed cotton yield per plant. The plant material was genotyped with 23 highly polymorphic simple sequence repeats markers. The cotton varieties, CIM-473 and FH-142, with higher content of carotenoid, chlorophyll, epicuticular wax, and proline maintained sustained vegetative growth and development due to osmoregulation; optimal photosynthesis and photochemical efficiency; and maintenance of balance in the C/N metabolism and energy homeostasis; which resulted in better seed cotton yield (> 30% than the drought susceptible varieties) under limited irrigation conditions. Significant associations of simple sequence repeat DNA markers with plant height, carotenoid content, chlorophyll content, wax content, and seed cotton yield were identified. Especially, the DNA markers BNL1153 (chromosome 25) and BNL3031 (chromosome 9) might be the markers flanking the genes involved in the biosynthesis of proteins/enzymes (such as Late Embryogenesis Abundant proteins; chaperones; antioxidants; L-ascorbate peroxidase; enzymes in the ABA, proline, carotenoids and epicuticular wax biosynthesis) catalyzing the metabolic pathways leading to water-deficit tolerance in cotton and thus would be valuable resources for molecular breeding programs to develop water-deficit-tolerant cotton cultivars.