ISHS Acta Horticulturae 116: Symposium on Postharvest Handling of Vegetables
PERFORMANCE OF NOR2 HYBRIDS OF TOMATO (LYCOPERSICON ESCULENTUM MILL.) DURING STORAGE AT CONTROLLED TEMPERATURES |
| Authors: | A. Sozzi, F.L. Gorini, G.P. Soressi |
| Abstract:
"Red" and "yellow-pink" fruits from the cvs UC-82 and Gimar, from their NOR2 hybrids and from the cv. Roma (test), were stored at 5°C and 12°C and examined after 30, 60 and 90 days. NOR2 hybrids performed better than cultivars but they showed a progressive fruit decay after 30 days storage. After 60 days storage, however, the quality of sound, NOR2/+ "yellow-pink" fruits was as good as the one of the normal "red" at harvest time. The temperature of 12°C extends the storage life of both "red" and "yellow-pink" fruits whereas 5°C is suitable only for storing "red" fruits for a month. These results emphasize the possibility of developing F1NOR2 hybrids with fruits able to be stored at 12°C maintaining acceptable characteristics for over a month. The non-ripening (NOR) mutant (Tigchelaar et al., 1973) and its NOR2 allele (Soressi, 1975) delay the ripening process of the tomato fruit by retarding carotene development partially suppressing respiratory level, poligalacturonase (PG) activity and ethylene production (NG and Tigchelaar, 1877). As a consequence the softening process of the fruit either on or off the plant is retarded (Buescher et al., 1976; Rossi, 1976; Allavena et al., 1978). Although the NOR gene has been described as a recessive one it exerts a profound effect on the ripening of the fruit from heterozygous at this locus. The NOR/+ fruits, in fact, have a storage life (Palmieri et al., 1975) and a PG activity (Buescher et al., 1976) intermediate to both parents. The reduced pectolytic activity in the fruit is probably responsable for the slower softening and for the enhanced storage life of NOR hybrid fruits which however attain an acceptable flavour, texture and colour. This appears of great interest for improving the keeping quality of tomato fruits as required by fresh market and processing (Palmieri et al., 1975; Buescher et al., 1976; NG and Tigchelaar, 1977; Allavena et al., 1978; Tigchelaar et al., 1978). This paper deals with the performance, in terms of ripening index, colour, firmness and other fruit quality parameters, of NOR2 hybrids during long storage at controlled temperatures. | |
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