Physiological and biochemical responses of palak (Beta vulgaris var. bengalensis) seeds to TNAU Vidhai Amirtham biopolymer coating

Palak (Beta vulgaris var. bengalensis), an important leafy vegetable, may exhibit poor and non-uniform germination. Seed coating with a bio-based polymer offers a low cost seed enhancement approach. A laboratory experiment was carried out at the Department of Seed Science and Technology, Tamil Nadu Agricultural University (TNAU), Coimbatore, to standardise the polymer-to-water ratio of TNAU Vidhai Amirtham, for Palak cv. All Green. Seeds were coated with 7, 8, 9 and 10 g polymer combined with 40, 50 and 60 mL water resulting twelve treatments along with hydropriming and untreated control with four replications in a completely randomised design (CRD) The 7 g polymer + 60 mL water treatment (T₃) recorded the highest germination (94 %), germination speed (9.81), root length (10.6 cm), shoot length (7.0 cm), vigour index I (1654) and vigour index II (0.658), significantly exceeding the untreated control, representing improvements of 34.3 % in germination and 96.9 % in vigour index I over the untreated control. T₃ also recorded the highest α-amylase activity (2.789) and dehydrogenase activity (1.921 OD), consistent with enhanced metabolic activity and reserve mobilisation during germination. Catalase and peroxidase activities showed no significant treatment effect, suggesting that antioxidant enzyme responses were not major determinants of the observed treatment differences. These results identify 7 g polymer + 60 mL water as the most effective TNAU Vidhai Amirtham coating combination for improving physiological and biochemical seed quality in palak, suggesting its potential as a low-cost, chemical-free seed enhancement strategy for improving field establishment and stand uniformity in leafy vegetable nurseries and seed production systems.