STUDY ON FIELD AND STORAGE PERFORMANCE IN TERMS OF DISEASES OF SIX BARI ONION VARIETIES

Abstract

The experiment was conducted in the field and store house of Spices Research Centre, BARI Shibganj, Bogura, Bangladesh during 2019-2020 to evaluate the field and storage performance of six varieties of BARI Piaz viz., BARI Piaz-1, BARI Piaz-2, BARI Piaz3, BARI Piaz-4, BARI Piaz-5 and BARI Piaz-6. The field experiment was conducted

for

producing bulbs and observing the field performance. In the field BARI Piaz-4 showed maximum plant height (50.39-71.50 cm), bulb length (7.57cm), bulb diameter (4.97cm), single bulb weight (71.33g) and yield (36.53t/ha). Where BARI Piaz-5 showed minimum plant height (43.05-58.61 cm), bulb length (4.84cm), bulb diameter (3.91cm), single bulb weight (41.17g) and yield (14.64 t/ha). On the other hand, highest disease incidence of purple blotch (4.19%) and Stemphylium (43.41%) were observed in BARI Piaz-5 where lowest disease incidence of purple blotch (3.49%) and Stemphylium (34.91%) were observed in BARI Piaz-4. After air dried the harvested onion bulbs of six varieties were stored in the store house. Bulbs were stored in a wooden structure under ambient condition. The average air temperature of the store house was 27.19-29.30℃ and humidity 61.63-80.90%. Different storage performances were recorded at an interval of 15 days viz., 15, 30, 45, 60, 75, 90, 105, 120, 135 and 150 DAI. Highest number of sprouted bulbs were observed in BARI Piaz3

at 15, 30, 45, 60, 75and 90 DAI. Where lowest number of sprouted bulbs were observed in BARI Piaz-4. Total percent of sprouted bulbs 8.51%, 38.51%, 46.34%, 14.33%, 29.67% and 15% were observed in V 1, V 2, V 3, V 4, V 5 and V 6 respectively. Highest number of rotten bulbs were observed in BARI Piaz-3 and lowest number of rotten bulbs were observed in BARI Piaz-4. Total percent of rotted bulbs 56.17%, 56.83%, 73.17%, 40.27%, 58.16% and 62.99% were observed in V 1, V 2, and V 6 respectively. At storage, total maximum bulb weight loss 78.70% was observed in BARI Piaz-3 where minimum weight loss 49.42% was observed in BARI Piaz-4. From the study it is found that BARI Piaz-4 performed best than the other varieties at storage. Where BARI Piaz-3 showed lower performance. Aspergillus niger, Fusarium sp. and Penicillium sp. have been found to cause diseases during postharvest storage condition. In this study, 65% rotten of onion bulbs by Aspergillus niger, 20% by Fusarium sp., 10% by Penicillium sp. and 5% by other pathogens were found.