Physiological and Yield Parameters of Multiplier Onion (Allium cepa l. var aggregatum Don.) var. CO(On)5 as Influenced by Zinc and Boron Application

The field experiment was carried out in the College Orchard, Horticultural College and Research Institute, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu during 2013 - 2014 to study the effect of zinc and boron on seedling transplanting of multiplier onion CO(On)5 at different levels of both foliar and basal application. The eleven treatments consisted of different combination of the soil and foliar application of zinc sulphate as zinc source and borax as boron source replicated thrice in a randomized block design. The foliar spray was given 30 and 45 days after transplanting for both zinc sulphate and borax. Nitrogen, Phosphorus, Potassium, and Sulphur were applied @ 90-60-60-20 kg ha?1, respectively as basal dose. Results were found to be significant in most of the physiological and yield contributing parameters of multiplier onion. The total chlorophyll content (1.38 mg 100 g?1), total dry matter production (5.31 t ha?1) and bulb yield per hectare (16.9 t ha?1) were highest in zinc sulphate by 0.5% foliar spray. The highest benefit: cost ratio (2.08) was recorded in T3 (zinc sulphate foliar spray @ 0.5 % at 30 and 45 DAT).