Improving Onion (Allium cepa L.) Growth and Bulb Yield by Application of Salicylic acid and Azospirillum

The present investigation resulted that treatment (T17) Salicylic acid (250 mg/L) at 30 days after sowing and 30, 45, 60 days after transplanting with Azospirillum (5 kg ha−1) at 60 days after sowing was performed significantly superior over control such as highest plant height at harvest (49.97 cm), length of leaves (45.37 cm), number of leaf per plant (19.77), equatorial diameter (64.04 mm), polar diameter (61.40 mm), double bulb (0.33%), the lowest A, B and C grade bulb (38.49%), (66.37%) and (13.29%) respectively, bulb yield polt−1(14.90 kg), marketable bulb yield (28.53 t ha−1), total bulb yield high value in T11 (29.66 t ha−1). The minimum occurrence of purple blotch in month of February, March and April were recorded under (0.0%), (1.56%), (1.46%) respectively in T5-Salicylic acid (250 mg/L) at 30 days after sowing, 30, 60 days after transplanting followed by (T13) and (T17) over control T18. The minimum (0.0%) occurrence of stemphylium blight (January) was noted in T11-Salicylic acid (250 mg/L) at 30 days after sowing, 30, 45, 60 days after transplanting + Azospirillum (5 kg/ha) at 30 days after transplanting fallowed by (T13) and (T14). In February, March and April months it were noted under treatment (T17) and (T5) over control. The minimum (0.0%) occurrence of thrips in January was found under treatment (T11) and (T11) followed by (T12), (6.07%) occurrence in February was found under treatment (T17), (10.0%) occurrence in March was found under treatment (T17) followed by (T16) (T15), (7.12%) occurrence of thrips in April was found under treatment (T17) followed by (T5) (8.40%). The treatment (T11) recorded highest gross monitory return (Rs. 290660 ha−1) but net return (Rs. 225555 ha−1) and benefit cost ratio 3.44 recorded under (T12) followed by (T16) 3.42 and (T17) 3.40. However, minimum gross income (Rs. 220130 ha−1), net return (Rs. 155870 ha−1) with benefit cost ratio 2.42 was recorded in control.