Ethylene Production by Fruit of Some Slow-ripening Nectarine Genotypes

Abstract

Abstract The relationship between the ripening behavior and C2H4 production of 4 slow-ripening nectarine [Prunus persica (L.) Batsch] genotypes was investigated. While there was no change in C2H4 production and little ripening in fruit kept for one month in air at 20°C, continuous exposure to 1300 μl·liter−1 propylene (C3H6) stimulated ripening and C2H4 production in these genotypes. The concentration of 1-aminocyclopropane-1-carboxylic acid (ACC) in freshly harvested fruit was less than 0.05 nmol·g−1 and rose 6- to 8-times during the rise in C2H4 production. ACC levels remained low in preclimacteric fruit of all genotypes except P19-70, in which ACC concentration increased without an accompanying increase in C2H4 production. Wounding had little effect on C2H4 production by these 4 genotypes, but addition of one mm ACC stimulated C2H4 production by tissue plugs 35 to 70 fold. Delaying the harvest by up to 6 weeks had no effect on fruit weight or firmness, but flesh color and pH increased while titratable acidity and soluble solids content decreased; the onset of C2H4 production during storage at 20° was advanced, while the ability to convert ACC to C2H4 declined. In no case did C2H4 production rates by these fruit reach the levels of normal nectarine genotypes. We conclude that these slow-ripening genotypes lack the capacity to produce normal C2H4 levels for nectarines.