Effect of foliar applied gibberellin and salicylic acid on physiology and yield of black gram under delayed sowing condition in Assam

An experiment was carried out to examine the effects of foliar applied gibberellic acid (GA₃) and salicylic acid (SA) in improving the productivity of black gram under delayed sowing condition in Assam, India. Five black gram genotypes viz. LBG-752, PU-30, PU-40, AZAD URD-3 and LBG-645 were sown in three different dates viz. 15th September (D₁), 1st October (D₂), and 15th October (D₃) and were foliar applied with three treatments viz. water spray (T₁), 50 ppm GA₃ (T₂) and 500 µML^− 1 salicylic acid (T₃) before flowering stage. Significant variations were recorded due to the genotypes, treatments as well as sowing dates in the morpho-physiological, biochemical and yield attributing parameters studied. The plant height, leaf area per plant, whole plant biomass, total leaf chlorophyll content, nitrate reductase enzyme activity, number of pods and seed yield per plant exhibited a declining trend under delayed dates of sowing compared to that of sowing of seeds on 15th of September (D₁). However, the proline content and lipid peroxidation were found to be increased under delayed dates of sowing in all the genotypes. The sowing of seeds on 15th of September was found to be the ideal sowing date for black gram in Assam (India) under delayed sowing condition. Furthermore, the GA₃ treated plants showed the best performance for most of the traits as compared to salicylic acid and control (water spray) under all the sowing dates and in all the genotypes. The genotype LBG-645 showed the best performance followed by AZAD URD-3 under delayed sowing dates.