Effect of PGRs and Nutrients on Growth, Physiological Parameters and Yield of Vigna mungo L. under Saline Stress

Abstract

Aim: Pots culture experiment was conducted in order to alleviate the salinity effect in Vigna mungo L. using plant growth regulators and nutrients by assessing growth, physiological and yield parameters. Study Design: The experiment was carried out with seven treatments of different PGRs and nutrients with three replications organized in a complete randomized design. Place and Duration of Study: The experiment was conducted in glass house, Department of Crop Physiology, TNAU, Coimbatore, Tamil Nadu, India during 2016. Methodology: Red sandy soil mixture was used for pots culture experiment using medium size pots with 12 kg capacity. The salinity was imposed by 125 mM NaCl concentration. Plant growth regulators and nutrients like jasmonic acid (50 µM), gibberellic acid (10 ppm), brassinolide (0.5 ppm), salicylic acid (100 ppm), ascorbic acid (100 ppm), benzyl amino purine (5 ppm), K2SO4 (0.5%) + FeSO4 (0.5%) + Borax (0.3%) and TNAU Pulse Wonder (1%) were used as foliar spray at 20 and 40 days after sowing except jasmonic acid, which used as seed soaking. The plant height, root length, chlorophyll content, soluble protein content, proline content and NR activity were estimated at 30 and 50 days after sowing. Finally the yield was recorded during harvest. Results: Salinity significantly reduces the plant height, root length, chlorophyll and soluble protein contents, NR activity and yield. However, the proline content was increased under saline condition over absolute control. Among the PGRs and nutrients, 0.5 ppm brassinolide showed its supremacy in terms of increased plant height, soluble protein, NR activity and yield compared to other treatments. However, benzyl amino purine recorded higher chlorophyll content (2.25 mg g-1) followed by TNAU Pulse Wonder (2.12 mg g-1) and brassinolide (2.04 mg g-1). Brassinolide registered the highest proline content of followed by ascorbic acid and TNAU Pulse Wonder. Brassinolide increased nitrate reductase activity up to 36.78 per cent followed by salicylic acid (32.18%) over control. Brassinolide recorded the maximum grain yield of 8.85 g plant-1 followed the salicylic acid (8.72) which is on par with TNAU Pulse Wonder (8.60 g). Conclusion: Salinity causes 40 per cent yield reduction in black gram. All the PGRs and nutrients improved the growth and yield of black gram under salinity. Brassinolide showed its supremacy of 21.07 per cent yield increment under salinity followed by salicylic acid (16.98%) and TNAU Pulse Wonder (13.21%).