Effect of different set sizes, spacings and nitrogen levels on the growth and bulb yield of onion

Influence of two set sizes viz. 1 .6 and 2.44g/set, three plant spacings viz. 20cm x 1 0cm, 20cm x 15cm and 20cm x 20 cm and four doses of N viz. 0, 60,120 and 180 kg/ha on the growth and bulb yield of onion was studied. Larger set produced the highest bulb yield (22.6t/ha) over smaller one (19.9 t/ha) . Smaller set gave more number of single bulbs and took shorter growing period. The closest spacing produced the maximum number of single bulbs (31.6%) and the highest bulb yield (23.7 t/ha). N at zero level gave the highest number of single bulbs. N at 120 kg/ha produced the maximum bulb yield (28.5 t/ha), but N at 180 kg/ha gave the highest plant height and required the longest growing period. Interaction effects of all possible combinations caused significant variation on bulb yield and related components. Larger set with the closest spacing gave the highest bulb yield (25.6 t/ha). Smaller set with nitrogen at zero level produced the maximum number of single bulbs. The closest spacing with 120 N/ha gave the highest bulb yield (31.6 t/ha). Maximum bulb yield (33.7 t/ha) was recorded from the combination of larger set x closest spacing x 120 kg N/ha. Smaller set x closest spacing x zero level N produced the highest number of single bulbs.