An experiment was conducted at Horticultural College & Research Institute to find out the response of aggregatum onion to different spacing and levels of organic, inorganic and biofertilizers in respect of bulb diameter, bulb length, shape index and flowering. The experiment was laid out in split plot design with 30 treatments replicated thrice. Three spacing viz., S, 45x5, S, 45x10, and S, 45x15 cm formed the main plot treatments. The subplot treatments consist of 10 combinations involving three levels of N (20, 40 and 60 kg ha), three levels of P (20, 40 and 60 kg ha') and constant level of K (30 kg ha) along with FYM 25 tha, Azospirillum at 2 kg ha' and phosphobacterium at 2 kg ha'. An organics alone and absolute control without nutrients were also adopted. The increase in length of bulb and shape index were higher at closest spacing of 45x5 cm, while the widest spacing of 45x15 cm registered the greater bulb diameter. Manurial treatments had significant influence on the bulb characters, which showed an increasing trend with increasing level of nutrients. Spacing and nutrients had no influence on the days taken for flower initiation, days to 50 per cent flowering and days for maturity. Interaction effect revealed that application of 60:60:30 kg NPK ha, FYM. at 25 t ha, Azospirillum at 2 kg ha and phosphobacterium 2 kg hat along with closest spacing of 45x5 cm recorded the higher bulb length (5.70 cm) and shape index (1.09 %).
Muthuramalingam et al. (Mon,) studied this question.