Abstract
Coincidence of heat stress with reproductive stages of cotton accelerates phenology and deteriorates the quality of cotton fiber. A field study was conducted for 2 years to investigate the beneficial role of foliar selenium (Se) application in alleviating the adverse effects of heat stress on cotton growth, development and yield. The experiment was laid out in a randomized complete block design with split arrangement and replicated thrice. Three levels of heat treatment were assigned in the main plots, that is, H
0
= No heat stress; H
1
= Heat stress imposed at squaring and H
2
= Heat stress imposed at flowering. Four levels of foliar spray of Se at 0, 50, 100 and 150 mg/L were applied in each subplot. A remarkable decrease in phenology, quality attributes and seed cotton yield was observed under 'H
1
' and 'H
2
', compared to 'H
0
'. Similar improvements in phenology were recorded with all three doses of Se application, whereas only the highest Se dose 150 mg/L significantly improved seed cotton yield and fiber quality. Conclusively, heat stress was more detrimental at flowering than at the squaring stage for cotton crop in terms of the examined attributes. Application of Se at 150 mg/L is, therefore, recommended to alleviate heat stress, due to its proven beneficial effect on fiber quality and seed yield.