Carboxymethylcellulose Coating Improved Germination and Early Seedling Vigour in Carbendazim Dressed Onion (Allium cepa L.) Seeds

Poor germination, vigour and emergence are major constraints significantly reducing the yield potential of the onion farming. Being a high value crop, the present study was designed to comprehend the physiological basis of the seed coating-induced improvement in germination of onion seeds. Investigations were carried out in the years 2021 and 2022 amongst seeds coated with various coating reagents—carboxymethylcellulose, chitosan and sodium alginate in a completely randomized design in Seed Physiology Laboratory, Punjab Agricultural University, Ludhiana, Punjab, India. The current investigation documented that onion seeds dually coated with fungicide (3 g carbendazim 50% Wettable Powder per kg seeds) followed by 1% carboxymethylcellulose was the most efficient treatment in convalescing low-vigour onion seeds which significantly improved germination, seedling vigour and plant stand under field conditions. Efficient reserve mobilization, utilization of free amino acids for protein reconstitution and lowered seed damage indices including electrolye leakage, lipid peroxidation and advanced oxidation of protein products were identified as the physiological basis of coating-induced enhancement in germination and seedling vigour. This was coupled with up-regulated activities of dehydrogenase and α-amylase enzymes aiding in efficient mobilization of starch which provided high energy substrates like soluble sugars resulting in establishment of vigorous seedlings than untreated control.