Antioxidant and Physiological Responses of Upland Cotton Accessions Grown Under High-Temperature Regimes

Increased temperature caused by climate change is exerting negative impacts on productivity of cotton crop. Therefore, breeding cultivars tolerant of high temperature are need of the time. Realizing the situation, 154 accessions of upland cotton were sown under alpha lattice design in three replications in two sowing dates. The first sowing date was planned to coincide the flowering stage with maximum annual temperature (± 48 °C) of the region. The data were recorded at appearance of first flower for physiological traits like viability of pollen grains and cell membrane thermostability. Enzymatic and non-enzymatic antioxidants, i.e., peroxidase activity and proline contents were also quantified along with hydrogen peroxide. K-means cluster and biplot analysis revealed the differential response of genotypes. FH-Lalzar, IUB-13, GH-Mubarak and Shahkar exhibited higher values for antioxidants and physiological traits. The yield and fibre quality of these genotypes were also superior as compared to others. It was suggested that diversity in germplasm for aforementioned traits can be utilized in further breeding programs.