Effect of soluble silica on the plant growth, leaves chlorophyll content and bulb quality of the garlic (Allium sativum L.) against drought stress

Garlic is an aromatic spice with nutritional and medicinal values. Climatic variations such as drought, adversely affect Garlic’s morpho-physiological, biochemical attributes and diminish its bulb quality. Soluble silica is a plant-available form of silicon (Si). Silica is beneficial for plant’s healthy growth especially against stress conditions. The present study was aimed to evaluate the effect of soluble silica on the garlic plant growth, leaves chlorophyll content and bulb quality against drought stress.

Garlic was cultivated during the Rabi season (2019-2020) in the experimental field Lohar pipliya (Dewas), India. Randomized experimental blocks consisted of six treatments as follows: T₁-Control (well-watered), T₂-Drought stress (water supply reduced by about 50%), T₃-Drought + a basal dose of NPK fertilizers (BDF) in soil, T₄, T₅, T₆-Drought + BDF + foliar sprays of 7.5, 10 and 12.5 ml L^-1 soluble silica respectively. Silica sprays were applied seven-time at a regular interval of 15-days. After 120days of sowing, plant growth in terms of plants height and number of leaves plant^-1 were measured. 120-days leaves chlorophyll, MDA and proline content were estimated. Garlic bulb’s quality in terms of fresh-dry weight and diameter were recorded at the final harvest.

Results revealed that drought significantly reduced Garlic’s plant height, bulb quality (weight and diameter), chlorophyll (Chl-a and Chl-b) and increased MDA, proline content in contrast to the well-watered garlic. Fertilizers (BDF) feebly improved garlic bulb quality. However, fertilizers (BDF) supplemented with soluble silica sprays (7.5 ml L^-1<12.5 ml L^-1<10 ml L^-1) significantly increased plant height, bulb weight and diameter, leaves chlorophyll, proline and reduced MDA content over the drought-stressed Garlic. Fertilizers (BDF) supplemented with Soluble silica maintained plant water content, reduced oxidative stress and increased leaves chlorophyll content. These resulted in good quality garlic bulbs in terms of weight and diameter despite the drought stress.