G. NARENDRA*, T. RAGHAVENDRA, K. MOHAN VISHNU VARDHAN, D. VENKATESH BABU AND P. LATHA

Department of Crop Physiology, S.V. Agricultural College, ANGRAU, Tirupati-517 502.

ABSTRACT

A field experiment was conducted during Kharif 2024 at RARS, Nandyal to study the impact of plant growth regulators on photosynthesis and yield Parameters in high-density of cotton. The Bt cotton hybrid Navneeth-BG II was grown under three different spacings (90 × 60 cm, 90 × 30 cm, and 90 × 15 cm) and with four treatments including control, detopping at 20th node, mepiquat chloride at 50% squaring, mepiquat chloride at 50% squaring and 50% flowering applications. Results showed that wider spacing improved physiological traits like photosynthesis and stomatal conductance, while closer spacing produced higher seed cotton and lint yields due to higher plant population. Application of mepiquat chloride, especially at 50% squaring, enhanced boll number, yield, and source–sink balance. The combination of closer spacing and mepiquat chloride at 50% squaring proved most effective for maximizing yield and improving physiological efficiency under high-density planting.

KEYWORDS: Bt-cotton, Detopping, HDPS, Mepiquat Chloride, Navneeth BG II.