FRUIT AND SEED DEVELOPMENT IN SUBTROPICAL PEACH CULTIVARS OF DIFFERENT RIPENING SEASONS

Fruits and seeds growth and development of six peach (Prunus persica L . Batsch) cultivars: Fla. 7-3 (ultra-early-maturing), Tropical (very e arly-), Joia-I (early-), Talisma (mid-), Biuti (late-) and Bolao (very late-) were measured from bloom date through harvest season in the Ju ndiai region (23-degrees-08'S), Sao Paulo State, Brazil. The period of duration of the stages I, II and III was determined for all cultivars . The results showed that about 98,5% of the fruit growth and developm ent occurred during the stages I and III. During the stage II, with a duration of 10 +/- 2 days, the mean fruit weight increased only one gr am, indicating the effects of the auxinic substances that decrease fle shy mesocarp growth and promotes pit hardening. Twenty days before mat uration, Fla. 7-3 and 'Tropical' duplicated the diameters and octuplic ated the fruit weights; the other cultivars presented a lower fruit de velopment. The integuments reached their maximum size at the end of st age II, when the embryo enhanced the development. The ultra-early and very early-maturing peach cultivars presented smaller embryos and litt le dry matter quantity. The Fla. 7-3 pits fissured mostly, aborting th e embryos by the rupture of vascular bundles.