Comparative Postharvest Losses of Short Day Onion (Allium cepa L.) Cultivars in Uncontrolled Storage Conditions

This research was conducted at the Behbahan Agriculture Research Station, Behbahan, south-west of Iran, for two years from 2016 to 2018 to study the postharvest losses of short-day onion cultivars in uncontrolled storage conditions (no heating, cooling and ventilation systems). Seeds were sown in nursery in early October and seedling transplanted at 2-3 leaf stage. Bulbs were harvested when 50-80% of foliage had dried and fallen and prepared for the experiment in both years. In the 1st year of experiment, the average of daily storage temperature and relative humidity ranged from 14.5 to 40.5°C and 27 to 60%, respectively. The average of daily storage temperature and relative humidity varied from 15 to 38 °C and 30 to 71%, respectively, in the 2nd year of experiment. This research was performed using a split plot experiment based on a randomized complete block design encompassing 80 treatments with 4 replications. Main plot consisted of 10 cultivars (‘Seba’, ‘Texas Early White’, ‘Imperateriz’, ‘Siroos’, ‘7030’, ‘X P red’, ‘Sapidan’, ‘Golden I’, ‘Texas Early Grano’ and ‘Primavera’) and bulbs evaluation in storage  at eight times  (one months after  start of storage with one month interval) was considered as sub plot. The monthly bulb weight losses percentage decreased with time. The minimum weight loss (9.56%) was recorded in ‘Seba vultivar. The damage of black mold increased until the fourth month of storage and then decreased. ‘Sapidan’ was the most sensitive cultivar to damage of black mold (23.23%). The highest percentage of bulb rotting (29.65%) was observed in ‘Texas Early White’ cultivar. Bulb sprouting was observed from the fifth month of storage and the highest bulb sprouting (19.88%) belonged to ‘Siroos’ cultivar. Results were suggestive of difference in storability among cultivars, the maximum and minimum storability being recorded in ‘Seba’ and ‘Sapidan’, cultivars, respectively.