Effect of Planting Date, Spacing and Nitrogen Level on Growth, Yield and Quality Seed Production of Onion (Allium cepa L.)

Abstract

The experiment was conducted at the Agronomy Field Laboratory, Department of Agronomy and Agricultural Extension, University of Rajshahi during the period from October 2008 to April 2009 to study the effect of planting date, plant spacing and levels of nitrogen on the growth, yield contributing characters, yield and quality of onion seed. There were three planting dates viz. November 05, November 25 and December 15; four plant spacings viz. 25cm x 10cm, 20cm x 15cm, 25cm x 15cm and 25cm x 20cm and four nitrogen levels viz. 0 Kg ha·1, 100 Kg ha·1 , 150 Kg ha·and 1 200 Kg ha· • The experiment was laid out in Split-Split plot Design having three replications. The planting dates were assigned in the main plots, plant spacing in the sub plot and the nitrogen level in the sub- sub plots. The size of each unit plot was 1.5 m x 1.0 m. The results of the experiment revealed that planting date had significant effect on all the parameter studied except plant heights at 30 DAP. Plant spacing and nitrogen levels were also significant on vegetative growth, yield contributing traits, yield and quality of onion seed. Planting date November 05 gave the tallest plant, highest number of leaves planf1 , tillers planf1 , number of umbels planr1 , number of flowers umber1 , number of seeded fruits umber1 , highest percentage of fruit set, seed weight umber1, thousand seed weight, germination percentage of seeds and finally produced highest seed yield (482.46 Kg ha.1 ). The lowest values of all the parameters were found in the planting date Decemberl 5 except days to 50% bulb emergence. Planting bulbs with closer spacing gave the highest seed yield unit area·1 whereas bulbs with wider spacing produced the highest seed weight planf1 • The closest spacing of 25 x 10 cm2 produced the highest seed yield ha.1 (501.39 kg) but the seed yield planf1 was higher (1.41g) in widest spacing of 25 x 20 cni. --------