Effect of Plant Growth Regulators on Physiological Productivity and Seed Quality of Soybean [Glycine Max (L.) Merill]

The current study was carried out on soybean variety JS 20-98 seeds that were treated to varying concentrations of plant growth regulators (PGRs). These seeds were used in field studies using Randomised Block Design (RBD) with four replications, and the observations were recorded on phenophasic observations, such as days to 50% flowering, days to pod formation, days to seed formation, days to physiological maturity, and days to field maturity.Determination of dry matter production and its partitioning in various plant parts (leaves, branches, main stem, and pod) at 45 DAS, 60 DAS, 75 DAS, and 90 DAS. Physiological obsdervations (Growth analytical parameters), Leaf Area Index (LAI), Leaf Area Duration (LAD), Crop Growth Rate (CGR), Relative Growth Rate (RGR), Specific Leaf Area (SLA), Specific Leaf Weight (SLW), Biomass Duration (BMD), Chlorophyll Content Index (CCI), Relative Water Content (RWC). Yield and yield components included viz; plant height (cm), number of branches plant-1, number of pods plant-1, number of seeds pod-1, pod length (mm), pod width (mm), pod girth (mm), seed index (g), seed yield (g plant-1and kg ha-1), biological yield (g plant-1 and kg ha-1), harvest index (%). The biochemical estimation includes moisture (%), ash (%), crude fibre (%), total carbohydrate (%), protein (%), and fat (%). However, seed quality traits include germination (%), seedling length (cm), seed vigour index-I, seed vigour index-II, seedling dry weight (g), root length (cm), and shoot length (cm) in soybean. The treatment GA @ 3 ml L-1 (T5) produced the highest seed yield of 2429.93 kg ha-1, biological yield of 6804.47 kg ha-1, and harvest index of 35.71% among the six PGR treatments on soybean. The greatest value for seed quality parameters, especially germination (%), seedling dry weight (g), seedling length (cm), seed vigour index-I, and seed vigour index-II was recorded under the treatment GA @ 3 ml L-1 (T5).