POTENTIAL MATURITY INDEXES AND DEVELOPMENTAL ASPECTS OF MELTING-FLESHAND NONMELTING-FLESH PEACH GENOTYPES FOR THE FRESH-MARKET

Potential maturity indices were determined for two melting-flesh (FL 9 0-20 and 'TropicBeauty') and two nonmelting-flesh ('Oro A' and Fl 86-2 8C) peach [Prunus persica (L.) Batsch.] genotypes. A range of developm ental stages was obtained by conducting two harvests and separating th e fruit based on diameter. Fruit in each category were divided into tw o groups. One group was used to determine potential maturity indices: soluble solids, titratable acidity, soluble solids to titratable acidi ty ratio, peel and flesh color on the cheeks and blossom end, cheek an d blossom-end firmness, ethylene production, and respiration rate. The other group was stored at 0 degrees C for 1 week and ripened at 20 de grees C for 2 days to simulate handling conditions and presented to a trained sensory panel, which rated the fruit for three textural aspect s (hardness, rubberiness, and juiciness) and six flavor aspects (sweet ness, sourness, bitterness, and green, peachy, and overripe character) . Principal component (PC) analysis was used to consolidate the result s of the descriptive sensory evaluation into a single variable that co uld be correlated with the objective measurements at harvest. The attr ibutes that best correlated with the first sensory PC of each genotype , and thus are promising maturity indices, were as follows: for FL 90- 20, peel hue, peel L, and cheek firmness; for 'TropicBeauty', peel L, cheek firmness, and blossom-end firmness; for 'Oro A', cheek firmness, blossom-end firmness, and cheek chroma; and for 86-28C, blossom-end f irmness, cheek hue, and cheek firmness.