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Background: Salicylic acid (SA) is an endogenous plant growth regulator plays a vital role in plant growth, ion uptake, transport, interaction with other organisms and in the responses to environmental stress. The aim of the study was to find the effect of salicylic acid on chlorophyll content, superoxide dismutase and malondialdehyde level of leaves and seed yield parameters of soybean. Methods: Field trials were conducted during kharif 2018 and 2019 at ICAR-Indian Institute of Soybean Research, Indore farm (22.78°N, 75.88°E), India. Salicylic acid applied as foliar spray with (50,100 and 200 ppm) concentrations at vegetative stage (22-25 days after sowing) and at pod filling stage (57-60 days after sowing). Chlorophyll content, lipid peroxidation activity and superoxide dismutase enzyme, plant height, number of pod per plant, seed yield and seed index were determined. Result: Chlorophyll content, antioxidant enzyme were enhanced and the level of lipid peroxidation of leaves was reduced as compared to untreated plant when salicylic acid applied at critical stage of crop growth. Significant increase in soybean seed yield was observed both with concentration of 100 and 200 ppm salicylic acid. Foliar spray with salicylic acid @ 100 ppm at vegetative and at pod filling stage was very effective for better seed production programme to improve quantity as well as quality of soybean seeds. [ABSTRACT FROM AUTHOR]

The critical problem of soybean seed is susceptibility to mechanical processes due to structural limitations of seed and seed coat. The X-radiography of soybean seed revealed the orientation of seed coat around the cotyledons and cultivars like JS 335, JS 9752, JS 71-05, JS 95-60, MACS 124, Pusa 40, Punjab 1 and Type 49 had very compact seed coat around cotyledons. In NRC 12, NRC 37, RKS 18 and SL 525 where the gap between seed coat and cotyledons was significantly very high and non uniform making seed coat very much vulnerable to cracking. Seed coat minerals- calcium, silicon, zinc, iron and lignin content were found to vary significantly among cultivars. Significant genotypic variability for strength of seed coat was observed among the soybean cultivars. A very close relationship was found between strength of seed coat and seed coat compactness. Highly significant correlation was found between mechanical strength and seed coat lignin, iron and zinc content. Quantitative and qualitative variation for seed coat protein among soybean cultivars was revealed and higher protein content was found linked with mechanically strong seed coat. The result revealed that selection for these seed coat parameters in varietal improvement programme may be very fruitful for development of varieties having resistance to field weathering and mechanical damage. [ABSTRACT FROM AUTHOR]

Loss of seed quality in soybean is a serious problem in tropical and subtropical region. Foliar application of salicylic acid (SA), GA3 and acetyl salicylic acid (50 ppm) at seedling and pod filling stage, K2HPO4 (2%), α-tocopherol (100 ppm) at flowering and pod filling stage was done on soybean varieties -- NRC 7 and JS 335. Foliar application of SA showed positive effect on seed yield, seed health, germination and seed vigour during storage. Plant height was significantly improved by the GA3 spray in both the varieties. Significantly higher seed yield was obtained with foliar spray of α-tocopherol. Application of SA was found effective to protect plants from various diseases to get quality seed. α-Tocopherol and K2HPO4 treatment significantly reduced MDA production in seeds. α-Tocopherol application increased super oxide dismutase activity as a result the lipid peroxidation of seed during storage was significantly reduced. Application of α-tocopherol, K2HPO4 and salicylic acid improved the storage or keeping quality of soybean seed. [ABSTRACT FROM AUTHOR]