PHYSIOLOGICAL LOSS DURING STORAGE OF SWEET ONION IN REPUBLIC OF MACEDONIA

The local old sweet onion population 'buchinska arshlama' is mainly grown in the region of Pelagonia, South-West part of the Republic of Macedonia. It is traditionally grown by seedlings during the period of March until the middle of September. Growers commonly store this type of onion in bulk, covered with foil, without any controlled conditions. The aim of this study was to determine the physiological loss of the onion 'buchinska arshlama' stored traditionally and in cold rooms from October to April. The results show that although the mass of bulbs decreases, both in the traditional storage and in cold rooms, it was more advanced in traditional storage. Largest losses were measured at the end of storage period. The percentage of sprouted bulbs traditionally stored in all years (2010/2011, 2011/2012 and 2012/2013) was the highest in April and accounted for 32.06%, 10.85% and 40.22%, respectively, due to higher temperatures in that period. In cold room storage the percentage of sprouted bulbs is low and is the highest at the end of storage. The percentage of diseased bulbs depends on the year of production. This work confirms the existence of significant differences between storage conditions and production years during sweet onion storage, regarding physiological loss during storage period. Buchinska arshlama is well stored traditionally until the month of February. After that cold room storage is required in order to reduce the progressive physiological loss of bulbs.