Abstract

                                High temperature is a critical barrier in most cotton growing areas, limitingcotton growth and development. The present study aimed to evaluate theeffects of foliar spray on KC 3 cotton variety grown under ambient (32.66°C)and high temperature (37.21°C) stress in open-top chamber (OTC) with atemperature of 5°C from the ambient temperature for 10d from flowering toboll development stage. Foliar spray of kaolin @ 3% and calcium carbonate @5% were sprayed separately to the set of pots both in ambient and elevatedtemperature on 70th day of flowering. Observations on morphological andphysiological parameters were recorded on viz., plant height (cm plant-1), leafarea (cm2 plant-1), relative water content (%), canopy temperature (°C), SPAD,chlorophyll fluorescence (Fv/Fm ratio). Kaolin @ 3% foliar spray significantlyincreased the plant height, leaf area, relative water content, chlorophyllcontent and reduced the canopy temperature both in high temperature andambient temperature conditions. Among these treatments, T2 - kaolin 3%(Ambient) followed by T5 - Kaolin 3% (elevated temperature of 5 °C) recordedhigher values as compared to calcium carbonate treatment both in ambienttemperature and high temperature condition.

Key words : Cotton; High temperature; Foliar application; Morpho-Physiological parameters