Impact of Plant Growth Retardants and Detopping on Growth Parameters in Soybean (Glycine max L. Merrill)

Abstract

The present study was executed with the prime objective to study the effect of different concentrations of chlormequat chloride, paclobutrazol and detopping on morpho-physiological parameters of soybean variety NRC-37. The field trial was carried out inkharif 2023 at Department of Plant Physiology, Anand Agricultural University, Anand in randomized block design with ten treatments replicated thrice. The growth retardants were sprayed at 30 and 45 days after sowing. Detopping was done on 45 days after sowing. Morphological parameters like plant height and number of leaves per plant were recorded lowest with increasing concentrations of growth retardants. Paclobutrazol @ 100 mg/l recorded the lowest plant height and number of leaves per plant. Chlormequat chloride @ 750 mg/l promoted early flowering and recorded highest stem and total dry weight. Minimum values for leaf area index and leaf area ratio were observed with chlormequat chloride @ 750 mg/l and paclobutrazol @ 75 mg/l at different growth stages. Net assimilation rate and crop growth rate also observed similar trends recording higher values in chlormequat chloride @ 750 mg/l and paclobutrazol @ 75 mg/l at various crop growth stages. Foliar application of chlormequat chloride @ 750 mg/l or paclobutrazol @ 75 mg/l exerted a profound effect on the growth characters in soybean crop.