Abstract
Fruit picking requires maintaining high fruit quality throughout the picking process. Mechanization can reduce harvesting costs and dependence on seasonal labor. However, fresh fruit damage restricts mechanical harvesting and the number of fresh market crops currently mechanically harvested is small. Citrus production in Spain is primarily destined for the fresh market and citrus harvesting is only performed by hand. Apart from the variety, there are other factors that could affect citrus fruit damage susceptibility such as season, date of harvest, type of citrus fruit and other factors. It is important to assess the effect of different factors in citrus fruit damage susceptibility in order to determine varieties and conditions adequate for mechanical harvesting. Nine citrus varieties (clementines Orogrande and Marisol; oranges Navel lane late, Sanguinelli and Valencia late; hybrids Ortanique, Fortuna and Nova; and lemon Fino), along a five season period were evaluated. Two different experiments were carried out: field damage test and free dropping laboratory test. In the field test, fruit damage was calculated as the percentage of damaged fruit collected on the ground during mechanical harvesting. In the laboratory test, fruit damage was calculated as the percentage of damaged fruit in a free-falling test from 2 m height. Fruit damage was significantly related to citrus variety. Oranges and hybrids presented significantly higher fruit damage than lemons and clementines (21.3 % and 28.7% of damage fruit compared to 9.5 % and 10.8 % respectively). Orogrande fruit damage susceptibility during mechanical harvesting depended on the season. Fruit damage susceptibility was significantly higher in 2010 season and lower in 2008 season. Marisol fruit damage susceptibility during mechanical harvesting depended on the date of harvest. Damage susceptibility was significantly lower in the beginning of the harvesting season (October) compared to the end of the harvesting season (December). However in Valencia late no significant differences were found between damage susceptibility in April and in June. No significant differences were found between fruit damage susceptibility measured with field test and measured with free dropping laboratory test in Ortanique variety. Results have shown that citrus fruit damage susceptibility is related to variety, citrus fruit type, season and date of harvest.
