Soybean is highly sensitive to soil moisture stress. Due to climate change, erratic weather events hamper soybean production and productivity by disturbing the plant’s phenology, metabolism, and other physiological processes. Different seed rates, tillage, and drainage methods may have a high impact on the phenology and productivity of Soybean. Under flatbed sowing, the plant root will suffer from water logging due to high rainfall. In M.P., farmers apply high seed rates and narrow spacing of plants and rows to avoid less plant populations' risk. Under prevailing high-density planting, at the seed rate of 70 kg ha-1 and flatbed sowing method, plant growth is restricted due to limitation of radiation and nutrients. Hence, the seed rate and sowing method need revision in an era of climate change. Therefore, we hypothesized that adopting a lower seed rate under ridges and furrow sowing would improve phenology, seed yield, and seed quality over the prevailing seed rate of 70 kg ha-1 and the flatbed sowing method. Studies revealed that phenological development was significantly affected by seed rate during the entire span of Soybean. The minimal increment of 2.05 %, 2.53% on days to flower initiation, days to 50% flowering was observed in 50 kg ha-1. For seed quality attributes, 60 kg ha-1 was found to be superior in the enhancement of germination percentage (1.88%) and seedling length (2.36%) over control (70 kg ha-1). Ridges and furrows sowing method exhibited superiority for seed quality attributes in terms of enhancement in germination percentage (4.56%), seedling length (2.20%), vigour index I (1.46%), and vigour index II (3.0%). This proves our hypothesis that a lower seed rate of 60 kg ha-1 under ridges and furrows sowing method leads to improved seed yield and seed quality over 70 kg ha-1 flatbed sowing method. Hence, a reduced seed rate of 60 kg ha-1 under ridges and furrows sowing method has been recommended for realizing optimum soybean seed yield and quality under changing climate scenario.

Seed rate, sowing method, phenology, seed quality traits, soybean

Seed yield (g plant-1) is maximum at a reduced seed rate of 60 kg ha-1 due to reduced days to flower initiation, pod formation, and seed formation, physiological maturity and harvest maturity. Seed yield (g plant-1) is superior for ridges and furrows over the flatbed sowing method by 9.79%. The superiority of lower seed rate in seed yield per plant is due to the rapid progression of phenological stages, which might be due to lower plant density and better availability of light and radiation to the canopy. Seed yield (kg ha-1) is maximum at a higher seed rate of 70 kg ha-1 due to the higher plant population. Seed quality attributes viz., germination percentage and seedling length, seed vigour, i.e., seed vigour index I and II are not affected due to variation in seed rate, sowing method, and interaction.

Madhana Keerthana S, R. Shiv Ramakrishnan, Ashish Kumar, Nidhi Pathak, P.S. Pawar and Dibakar Ghosh (2022). Seed Rate and Sowing Method induced Variation in Phenology, Seed Yield and Seed Quality of Soybean [Glycine max (L.) Merill]. Biological Forum – An International Journal, 14(4a): 541-547.