Foliar applications of growth regulators (GR) in early autumn induced leaf retention (LR) on peach [Prunu,s persica (L.) Batsch.] and `Montmorency' tart cherry (Prunus cerasus L.) trees. In `Johnson Elberta' peach, the relative effectiveness of GRs on LR was NAA = Promalin (BA + GA4+7) > GA4+7 > GA3 > BA > control, and on leaf detachment pull force (PF) NAA > BA + GA4+7 > GA4+7 = GA3 > BA3 > BA > control. Relative GR-induced chlorophyll (CL) content in retained leaves was BA + GA4+7 > GA4+7 > GA3 > BA > control > NAA. Relative xanthophyll (XN) content of retained leaves was NAA > control > BA > GA3 = GA4+7 = BA + GA4+7. Treating only half of a peach tree with NAA did not affect LR on the untreated side. NAA decreased subsequent bud and flower size in peach. Bud hardiness was enhanced by NAA in `Johnson Elberta' peach but not in `Redhaven' peach or in `Montmorency' tart cherry. NAA increased hardening on both the leafy treated (foliated) and untreated (defoliated) sides of half-treated `Johnson Elberta' trees. Increased endodormancy duration, as measured by GA3 forcing of terminal leaf buds, was proportional to LR. Chemical names used: N-(phenylmethyl)- 1H-purin-6-amine (BA); (1a,2ß,4bß,10ß)-2,4a,7-trihydroxy-l-methyl-8-methylenegibb-3-ene-l,lO-dicarboxylic acid,l,4a-lactone (GA3, GA4+7); l-naphthaleneacetic acid (NAA).
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