Harvest time and storage of “Soreli” kiwifruit (Actinidia chinensis Pl.)

Abstract “Soreli” is a yellow-fleshed tetraploid selection of Actinidia chinensis developed at the University of Udine (Italy) and released in 2008. It crops heavily, ripens early-mid October in the northern hemisphere, and produces large, single fruit with intense yellow flesh color. Because they mature early in the season, fruit are sometimes harvested prematurely and the low quality of these fruit threatens the development of the cultivar in the market. We report in the present paper a two-year trial on harvest time (at approx. 7.0 and 8.5 °Brix), the monitoring of ripening in cool store and the final quality of fruit. The second year a treatment with 1-MCP (1-methylcyclopropene) in the cool store was included in the experimental plan. Fruit were stored in the cool store with temperatures maintained at 0.0  0.5°C with ethylene removed. Ripening was monitored at two-weekly intervals until February of the following year. Considering the two harvest times, fruit of the first harvest were firmer, but their soluble solids concentration (SSC) at consumption time was 0.7 °Brix lower than fruit harvested later in both years. Ripening followed rather different patterns in the two years. Firmness decreased rapidly the first year, but in the second year did not fall below 4 kg cm-2 until 4 February when the trial was stopped. The first year the soluble solid content reached c. 14 °Brix when fully ripe, whereas in the second season fruit reached only 12 °Brix, probably because of a long period of rain in May and the beginning of June. Treatment with 1-MCP when fruit entered the refrigerated cell enhanced fruit storage, with differences more evident in fruit harvested later in the season. Soluble solids content, acidity and dry matter content were not influenced by the 1-MCP treatment. No significant difference among harvesting time and 1-MCP treatment was recorded for the other parameters analysed, such as core firmness and flesh color. Remarkably no fruit decay was found amongst any of the samples.