Note. The ripening of Prunus persica fruits with a dominant flat allele

The changes of peaches (Prunus persica, L.) with a predominant flat allele were studied during their ripening on the tree. Physicochemical and physiol ogical parameters were analyzed between days 101 and 121 after fruit set. D uring this period, the weight ranged from 65 g (corresponding to fruit grow th stage III) up to a stabilized weight of 90 g when the fruit was ripe. Th e color changes that characterized fruit ripening began to appear on day 11 2 after fruit set, with a decrease in the hue angle value both in the skin and pulp. Firmness diminished along the experience from 6.75 to 3.03 Monet units in ripe state. Ripened fruit was also characterized by a soluble soli d content of 13.43 degrees Brix and 0.178% malic acid as titratable acidity . The ripeness index increased throughout maturation from 25.41 at the outs et to 44.42 on day 112 after fruit set, and 75.45 at the end of the experim ent. The fruit showed a clear climacteric behavior with increased ethylene production and respiration rate. The onset in both processes started on day 112 after fruit set, reached a maximum on day 116, and decreased thereafte r. Changes in the content of free and conjugated 1-aminocyclopropane-1-carb oxylic acid (ACC) were coincident with those of ethylene evolution througho ut ripening. In regard to polyamine levels, putrescine showed a peak slight ly later than that of ethylene and ACC.