Heat stress at reproductive stages of cotton cause adverse effects on agronomic, physiological attributes and worsens the fiber quality of cotton. A field study was conducted to see the foliar spray of benzoic acid (BZA) could help to alleviate the negative effects of heat stress on agronomic, physiological quality traits of cotton. Two levels of heat treatment were assigned in the main plots, that was, H₀ = no heat stress; H₁ = heat stress imposed at squaring for the period of 7 days. Six levels of foliar spray of benzoic acid i.e. control, water spray, 0.25, 0.50, 0.75 and 1.00 mM were applied in each subplot during heat stress imposition. The crop was sown on 75 cm apart ridges and plant to plant distance was maintained at 30 cm. All other agronomic practices were kept normal and uniform. The standard procedures were adopted for recording the data on various cotton parameters. A remarkable decrease in agronomic, physiological and quality attributes was observed under heat stress compared to control. Foliar application of benzoic acid significantly improved agronomic, physiological and fiber quality. Conclusively, heat stress was more detrimental at squaring for one week than no heat stress for cotton crop in terms of the studied traits. Foliar BZA 0.75 mM is, therefore, recommended to mediate heat stress, due to its beneficial effect on agronomic, physiological and fiber related parameters of cotton.

Key words: Cotton; fiber quality; Cell membrane thermostability; Chlorophyll; high temperature