SEED ENHANCEMENT FOR SUSTAINABLE AGRICULTURE: AN OVERVIEW OF RECENT TRENDS Debasish Panda* and Sananda Mondal Department of Crop Physiology, Institute of Agriculture, Visva-Bharati, Sriniketan-731236 (West Bengal), India. Abstract Seed enhancements are post-harvest treatments that improve the performance of seeds such as germination, seedling growth and facilitate the delivery of seeds and other planting materials required at the sowing. Seed quality plays an important role in crop production and lack of quality seed is one of the major hindrances in bridging the yield gap. Seed enhancement process involves pre-sowing hydration treatments or priming, hardening, coating technologies, seed conditioning and pregermination but excludes treatments for control of seed borne pathogens. Some of the recent advances in seed enhancement techniques include nano-priming which involves soaking seeds in nano-particle solutions followed by drying and magneto priming which involves exposing of seeds to magnetic field. In magneto priming, magnetic field is used as a non-invasive physical stimulant to improve seedling vigour and stress tolerance of the crop in the field. Nanopriming can augment performance of seeds in many ways such as enhancing -amylase activity, increasing soluble sugar content to support early seedlings growth, up-regulating the expression of aquaporin gene in germinating seeds, increased stress tolerance through lower ROS production, creation of nanopores for enhanced water uptake etc. This paper reviews the scope and relevance seed enhancement for sustainable agriculture with a special emphasis on recent advances in seed priming technologies. Key words: seed enhancement, seed priming, germination, magnetopriming, nanopriming. Introduction Seed is the most important input for crop production. Availability of quality seeds of different crops is considered very crucial for achieving higher productivity of crops. The quality of seed is known to contribute greatly towards increase in yield and lack of quality seed adversely influences the production of food grains. Faster and uniform germination of seeds and seedling emergence are the vital factors that determines better field stand of crops (Mahakham et al ., 2017). The process of seed germination starts with uptake of water by the seed through imbibition and terminates with the protraction of the embryonic axis, typically the radicle, through the seed envelope resulting in the protrusion of root followed by shoot (Rajjou et al., 2012; Mahakham et al ., 2017). The performance of seeds in terms of germination, seedling growth and vigour can be increased by seed treatments involving numerous invigoration techniques. The techniques of seed invigoration are not new and there is evidence of pre- sowing soaking of seeds in water and honey to invigorate them by the farmers of ancient Greek civilization (Evenari, 1980). Invigoration of seeds involving different organic and inorganic substances have been developed and practiced by the farmers over the years. Seed enhancement or invigoration includes a wide variety of treatments of seeds which improves their performance attributes like germination and early seedling growth. Some of the commonly used seed enhancement methods are priming, steeping, hardening, pregermination, pelleting, coating, encrusting, etc. but they exclude treatments for management of seed borne pathogens. This seed invigoration technology which includes a range of physical, physiological and biological treatments helps the seed to overcome different germination constraints and favours uniform crop stand, early development and higher yields of crops (Afzal et al ., 2016). While conventional seed treatments are intended to eradicate the seed borne pathogens and pests, seed enhancement aims at invigoration of seeds to Plant Archives Vol. 20 Supplement 1, 2020 pp. 2320-2332 e-ISSN:2581-6063 (online), ISSN:0972-5210 *Author for correspondence : E-mail: debasishpanda0007@gmail.com