Effect of foliar spray of hydrogel and salicylic acid on growth parameters of late-sown Indian mustard (Brassica juncea L.) under rainfed conditions

Introduction

Indian mustard (Brassica juncea L.) is an important oilseed crop grown extensively in India during the Rabi season. It belongs to the family Brassicaceae and is valued for its edible oil and proteinrich seed meal. The crop plays a vital role in meeting the edible oil requirement of the country and contributes significantly to the income of farmers, particularly in rainfed agricultural areas. Mustard is cultivated under a wide range of climatic conditions, but its productivity is often affected by moisture stress and unfavorable environmental conditions. Late sowing is one of the major factors responsible for reduced growth and productivity in mustard. Delayed sowing exposes the crop to lower temperatures during early growth and higher temperatures during reproductive stages, which negatively affect vegetative development and overall crop performance. Under rainfed conditions, insufficient and uneven rainfall further aggravates moisture stress, resulting in poor plant growth, reduced branching, and lower chlorophyll formation. Limited soil moisture also restricts nutrient absorption and physiological activities within the plant, ultimately leading to weak crop growth and reduced yield potential. Growth parameters such as plant height, number of branches per plant, and chlorophyll content are important traits that determine the growth and vigor of mustard plants. Better vegetative growth helps in efficient utilization of sunlight, improved photosynthesis, and higher dry matter production. Therefore, improving these growth characteristics is essential for obtaining better crop productivity under moisture-limited conditions. Hydrogel is a moisture-retaining polymer that can absorb and store large quantities of water and release it slowly according to crop requirement. Its application in soil helps maintain adequate moisture around the root zone and reduces the harmful effects of drought stress. Hydrogel also improves water use efficiency and supports better plant growth under rainfed conditions. The use of hydrogel has gained importance in dryland agriculture because of its ability to conserve soil moisture and improve crop establishment. Salicylic acid is an important plant growth regulator involved in various physiological and biochemical activities of plants. It helps plants tolerate stress conditions by improving photosynthesis, chlorophyll synthesis, nutrient uptake, and enzyme activity. Foliar application of salicylic acid has been found effective in promoting plant growth and enhancing stress resistance in many crops. It also encourages cell division and vegetative development, leading to improved plant height and branching. The combined use of hydrogel and salicylic acid may help improve growth performance of late-sown mustard under rainfed conditions. Hydrogel ensures better moisture availability, while salicylic acid enhances physiological efficiency and stress tolerance in plants. Their combined effect may improve plant growth and overall crop performance under moisture stress conditions. However, limited information is available regarding the effect of hydrogel and salicylic acid on growth parameters of late-sown mustard grown under rainfed environments. Keeping these facts in view, the present investigation entitled "Effect of Foliar Spray of Hydrogel and Salicylic Acid on Growth Parameters of Late-Sown Indian Mustard (Brassica juncea L.) under Rainfed Conditions" was undertaken to study the influence of hydrogel and salicylic acid on plant height, number of branches, and chlorophyll content of mustard under moisture stress conditions. Hydrogel is a super absorbent polymer capable of absorbing and retaining large quantities of water in the soil and releasing it gradually according to plant requirement. Application of hydrogel improves soil water holding capacity, reduces moisture loss, and maintains favorable moisture conditions around the root zone. Under rainfed conditions, hydrogel helps plants tolerate drought stress by ensuring continuous water availability during critical growth periods. Hydrogel application has also been reported to enhance nutrient availability, root growth, and dry matter accumulation in several field crops. Salicylic acid is an important plant growth regulator and signaling molecule involved in regulating physiological and biochemical processes in plants. It plays a significant role in enhancing plant tolerance against abiotic stresses such as drought, salinity, and temperature fluctuations. Foliar application of salicylic acid improves chlorophyll synthesis, photosynthetic activity, enzyme function, nutrient uptake, and cell division. It also promotes vegetative growth and improves physiological efficiency of crops under stress conditions. Application of salicylic acid has been found beneficial in increasing plant height, branch formation, and chlorophyll content in many oilseed crops. The combined use of hydrogel and salicylic acid may provide an effective approach for improving growth performance of mustard under late-sown rainfed conditions. Hydrogel helps in conserving soil moisture, while salicylic acid enhances physiological activities and stress tolerance in plants. However, information regarding their combined influence on growth parameters of Indian mustard under moisture stress conditions is limited. Therefore, the present investigation entitled "Effect of Foliar Spray of Hydrogel and Salicylic Acid on Growth Parameters of Late-Sown Indian Mustard (Brassica juncea L.) under Rainfed Conditions" was undertaken to evaluate the effect of hydrogel and salicylic acid on important growth parameters of mustard and to identify suitable treatments for improving crop growth under rainfed conditions.

Materials and Methods

The present investigation entitled "Foliar Spray of Hydrogel and Salicylic Acid on Late-Sown Indian Mustard (Brassica juncea L.) under Rainfed Conditions" was conducted during the Rabi season of 2025-26. The details regarding the materials used and experimental techniques adopted during the course of study are described in this section. The field experiment was carried out under normal field conditions at the research farm of the Department of Agronomy, Faculty of Agricultural Sciences and Allied Industries, Rama University, Kanpur-209217, Uttar Pradesh. The experimental farm is situated in the central-western region of Uttar Pradesh and is geographically located at 26.449923° North latitude and 80.331874° East longitude, with an elevation of approximately 567 meters above mean sea level. The region experiences a subtropical climate with distinct summer and winter seasons, which is suitable for cultivation of mustard during the Rabi season under rainfed conditions.

Result and Discussion

The foliar application of hydrogel and salicylic acid significantly improved plant height of Brassica juncea under late-sown rainfed conditions at all growth stages. Plant height increased progressively from 40 DAS to 80 DAS in all treatments. The lowest plant height was recorded in the control treatment (T₁), while the highest values were observed in T₇ (salicylic acid @ 150 ppm). Among hydrogel treatments, T₄ performed best. Salicylic acid treatments showed superior performance over hydrogel treatments due to improved photosynthetic activity, better nutrient uptake, enhanced cell elongation, and increased moisture stress tolerance. The results indicated that salicylic acid effectively promoted vegetative growth in mustard.

Number of branches plant -1

The foliar application of hydrogel and salicylic acid significantly increased the number of branches per plant in Brassica juncea under late-sown rainfed conditions. Branch formation improved continuously from 40 DAS to 80 DAS in all treatments, indicating better vegetative growth with crop advancement. The control treatment (T₁) recorded the lowest number of branches at all growth stages. Among all treatments, T₇ (salicylic acid @ 150

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