MULTIVARIATE-ANALYSIS OF WITHIN-TREE FACTORS ACCOUNTING FOR THE VARIATION OF PEACH FRUIT-QUALITY

The colour, firmness and flavour of 101 peach fruit from the south side of the tree were related to the characteristics of fruit-bearing shoots using a multivariate approach. The variability of quality was high between fruit. Fruit from the upper parts of the tree were more purple, less orange-red, less firm, had a higher sucrose content, a lower citric acid content and a higher pH than fruit from the lower parts. Fruit well exposed during the day had a purple skin, whereas less exposed fruit were more orange-red and had higher luminance (L*) and chrominance (a*, b*). Fruit exposed to light essentially in the afternoon were more purple, less yellow and orange and more firm, had a higher citric acid content, lower sucrose and malic acid contents than fruit exposed to light in the morning. Colour variables were weakly correlated to the total leaf area. Fruit borne by thick shoots with high total leaf area, high leaf area per fruit late in season and a high yield were sweet and had high malic acid content. Sour fruit were linked with high total leaf area and high leaf area per fruit early in season. A semantic model for quality elaboration is proposed.