TAILIEUCHUNG - Abscission of fruiting structures in BT and non-BT cotton in relation to abiotic factors and agronomic intervention under rainfed condition

A two year field experiment was conducted to elucidate relation of abscission of fruiting structures in cotton (Gossypium hirsutum) with abiotic factors and effect of agronomic intervention viz., spacing (90 × 60 cm and 90 × 45 cm) and NPK levels (50:25:25, and 75: kg NPK ha-1 ) on abscission of fruiting structures, leaf reddening and chlorophyll content in Bt and non-Bt cotton of same genotype, following split plot design with 4 replicates at Akola. Abscission of fruiting structures increased linearly with increase in morning relative humidity and number of rainy days in a week. However, relations with minimum temperature, evening relative humidity and rainfall were non linear and varied according to their range. Minimum temperature range of 20-22 °C, evening relative humidity beyond 52% and rainfall more than 60 mm in a week were most critical for abscission. Bt cotton lost more fruiting structures through abscission, recorded maximum leaf reddening, but gave higher seed cotton yield. Whereas, non-Bt recorded maximum chlorophyll content. Spacing of 90 x 45 cm compensated abscission losses and recorded higher seed cotton yield than 90 x 60 cm. Application of 75: kg NPK ha-1 recorded higher seed cotton yield by minimizing abscission and leaf reddening with improvement in chlorophyll content but was at par with kg NPK ha-1. Thus, it can be conclude that to harness higher seed cotton yield under rainfed condition Bt cotton should be sown at 90 x 45 cm spacing and fertilized with kg NPK ha-1 . | Abscission of fruiting structures in BT and non-BT cotton in relation to abiotic factors and agronomic intervention under rainfed condition

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• Abscission of fruiting structures
• Abiotic factors
• Bt and non Bt cotton
• NPK levels
• Agronomic intervention