COMPARISON OF HORMONAL LEVELS IN NORMAL AND DWARF PEACHES

Hormonal levels of two cultivars "Bonanza", a brachytic dwarf phenotype, and "Cresthaven", a normal phenotype, were tested. Five fractions of GA-like substances, one of auxin-like materials and another having inhibitory activity of ABA were extracted from the shoots, the shoot apices and leaves removed in spring when the new growth was 45 and 60 mm long, respectively, and again in the fall just before leaf fall. For comparative purposes, shoot samples consisted of 15 sub-apical buds from the current season's growth while the apices were confined to the terminal 15 mm. Leaves were taken from these shoot samples.GA-like substances were assessed by the barley endosperm bioassay (Ryugo-Sansavini, 1972) and auxin-like and inhibiting substances by the wheat coleoptile straight growth bioassay (Filiti, Cristoferi, 1977).