Salinity Stress Alleviation by Foliar Bio-Stimulant, Proline and Potassium Nutrition Promotes Growth and Yield Quality of Garlic Plant

Soil salinity is one of the major yield-limiting factors for crop production in many agricultural regions all over the world. Besides following efficient management practices at the field scale to reduce accumulation of salts in the effective root-zone, the effective use of treatments to alleviate the effects of salinity stress and improve crop salt tolerance is a promising solution to ensure crop production in such adverse conditions. A field experiment was carried out to investigate the effect of foliar spray with plant-based biostimulant (i.e. with and/or without 3% yeast extract), three levels of proline (0, 25, and 50 mM), and combined with potassium fertilizers, as potassium sulfate, 48% K2O (0, 50, and 100 kg/fed.) on growth promotion, chemical composition of garlic leaves, bulb quality parameters as well as yield and its components of garlic plant grown under moderate saline soil. Results revealed that the interaction between foliar spray with yeast extract at 3% and proline at 50 mM combined with proper K level at 100 kg/fed., was the best interaction treatment for increasing vegetative growth parameters, i.e. plant height, number of leaves per plant, and mineral contents (N, P, K, S, Ca and Mg in leaves), and proline content of garlic leaves after 135 days from planting time, total yield/fed., and garlic yield quality parameters at harvesting time. In conclusion, the detrimental effects of salinity stress can be alleviated by stress tolerance-inducing compounds, such as yeast extract and proline with proper application rate of K fertilization during the growing season of garlic crop.