Response of Black Gram to Seed Biopriming with Facultative Halophilic Bacteria under Salinity

Abstract

Under high salinity conditions, plant growth promoting halophilic bacteria (PGPHB) can thrive and greatly encourage plant growth. The use of PGPHB is minimal and less discussed in sustainable agriculture and abiotic stress control. The focus of the current investigation is to improve the growth of black gram by inoculating with of halophilic bacteria under salinity stress. Four PGPHB bacteria, viz., Bacillus safensis strain Lewis_Bac_3 (HB-5), Pseudomonas stutzeri strain MN1 (HB-13), Staphylococcus xylosus strain C5 (HB-18) and Pseudomonas sp. (GP-21: reference strain) were inoculated to black gram seeds to evaluate their plant growth promoting ability at 4 dS m-1 and pH >8.5. Increase in root length, plant height, and number of branches have been reported in consortium treatment (T8), indicating that salinity does not affected black gram photosynthesis and nutrient absorption in consortium treatment. Corroborating evidence revealed higher nodulation and total nitrogen and phosphorous content in the same treatment, in comparison with control. Due to salinity stress, decreased blooming was reported in control, conversely, consortium treatment showed 29.3 flowers/plant. A positive correlation with yield was demonstrated by number of pods and seeds per pod of black gram. In addition, there is a strong association between pods per plant and the amount of flowers per plant, nutrient content, and length of root. The decrease in control plot yield was due to shoot and root development resulting from insufficient nutrients availability. In this study we also found positive correlation between% P in plant and yield. Hence, we conclude that PGPH bacteria helps in the reduction of salt stress and significantly increase black gram growth and yield under mild salinity stress.