Description and Postharvest Physiology of Some Slow-ripening Nectarine Genotypes

Abstract

The postharvest behavior of several slow-ripening nectarine genotypes that originated from ‘Fantasia’ was investigated. These fruit were firmer and greener than ‘Fantasia’, had higher phenolic compounds and soluble solids contents, a higher pH, lower titratable acidity, and equal or greater levels of total and reducing sugars. Changes in flesh color and firmness during storage were much slower than in ‘Fantasia’, but the rate of softening varied among the genotypes. Although all of the genotypes tested seemed to be climacteric-type fruit, the preclimacteric period at 20°C could exceed 1 month, and C 2 H 4 production was much lower than in ‘Fantasia’. Application of C 2 H 4 during the preclimacteric period stimulated respiration rates, with the maximum response occurring at 10 ppm. A 2nd application of C 2 H 4 resulted in a 2nd increase in respiration, as with nonclimacteric fruit. Incidence of internal breakdown generally was severe compared to ‘Fantasia’ following 4 weeks of storage at 5°, although the genotype P19-11 appeared to be somewhat resistant to chilling injury.