Efficiency of seed bio-priming technique for healthy mungbean productivity under terminal drought stress

Recently, drought-induced damaging impact in reducing the crop growth and development is drastically ranked at the top under various abiotic stresses. And especially water stress at the reproductive growth stages termed as terminal drought has become a severe threat for mungbean productivity. To mitigate the drought stress condition, “bio-priming” has emerged as a newly agronomic and sustainable technique in improving the mungbean production. A 2-year field study during Kharif season 2017–2018 was conducted to investigate the efficacy of rhizobacteria seed priming in mungbean (AZRI mung-06), at Agronomic Research Area, Department of Agronomy, Bahauddin Zakariya University, Multan, Pakistan. The experiment comprised two factors containing F_A (seed treatments, control (dry seeds), hydro-priming, silicon (Si)-priming, and bio-priming (mixture strains of Pseudomonas fluorescens+Rhizobium phaseoli)) and F_B (irrigation water-regimes at various growth stages including leaf formation (L), stem elongation (S)+flowering (F)+pod formation (P) containing treatments are normal irrigation (I_L+S+F+P) and terminal drought stress (I_F+P)). All the treatments were arranged in randomized complete block design under factorial design and were replicated thrice. Results indicated that the exposure of drought stress at flowering and pod formation stages hampered the morpho-physiological growth and yield of mungbean. Nevertheless, seed priming treatments particularly bio-priming were effective in alleviating the detrimental effects of drought stress. Bio-priming significantly increased the yield and yield components (seeds/plant, 1 000-grain weight and harvest index) of mungbean and regulated the activities/levels of antioxidants (superoxide dismutase, catalase, peroxidase, ascorbic acid, and total phenolics) under drought stress. Compared with the control, bio-priming increased the seed yield of mungbean by 8–12% under normal as well as drought stress conditions during both years of study. Bio-priming also improved the nutrient uptake behavior followed by Si- and hydro-priming treatments under terminal drought stress. The study emphasized the effectiveness of bio-priming as dual seed treatment method may be helpful for vigorous germination of mungbean production along with plant tolerance against terminal drought stress. Among the various treatments, plants treated with bio-priming technique compensated the grain yield due to having strong antioxidant defense system and better nutrient uptake behaviour under terminal drought stress. Economic analysis also concluded that bio-priming is the easiest, cost-effective, friendly, and sustainable approach for the maximization of the mungbean production.