GROWTH, YIELD AND QUALITY OF SOYBEAN AS INFLUENCED BY PLANT GROWTH REGULATORS AND THEIR STAGES OF APPLICATION

Abstract

A pot experiment was conducted at Sher-e-Bangla Agricultural University, Dhaka during November, 2013 to March, 2014 with a view to find out the influence of different plantgrowth regulators and their stages of application on the growth, yield and quality of soybean cv. BARI Soybean-6. The experiment was consisted of four plantgrowth regulators viz., Control (water) (H0), Salicylic acid 50 ppm (H1),Gibberellic acid(GA3) 100 ppm (H2),Kinetin500 ppm (H3) and four stages of application i.e., Vegetative stage (S1) at 25 Days after sowing (DAS), flower initiation stage (S2) at 40 DAS, pod initiation stage (S3)at 50 DAS and flower + pod initiation stage (S4) at 40 and 50 DAS.The two factor experiment was set up in a Randomized Complete Block Design (RCBD) with five replications. The different plant growth regulators and / or stages of application showed significant effect on plant height, chlorophyll content (SPAD value), average length of internode,100-seed weight, seed yield,harvest index, protein content and moisture percentage in seed of soybean. Results revealed that salicylic acid gave the highest seed yield (4.12 g plant-1), which was statistically similar to GA3 (3.52 g plant-1) and kinetin (4.09g plant-1). Application of plant growth regulators atflower + pod initiation stage was found to be the most effective that produced the highest seed yield (4.54 g plant-1), which was statistically similar to vegetative (3.54g plant-1) and flower initiation stage (3.15 g plant-1). Among the treatment combinations the application of salicylic acid at flower and pod initiation stage showed the highest seed yield and maximum proteincontent compared to those of other growth regulators. So salicylic acid acts an important role for increasing soybean yield as well as protein content, when it was applied at flower and pod initiation stage.