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The effects of silver thiosulfate (STS) on stored and freshly made cuttings of `Royalty' rose (Rosa hybrids) were examined in relation to rooting and subsequent budbreak. STS pretreatment at 0.5 mm during storage stimulated budbreak but decreased the percentage of cuttings that rooted and the number of roots. IBA at 4.9 to 9.8 mm inhibited budbreak but this effect was partially reversed by STS. Spraying the cuttings with 1.0 mm STS once daily during the first 5 days of the rooting period also reduced rooting but prevented IBA-induced leaf senescence. Ethephon and spermine, each applied at 0.5 mm before rooting, had no effect on rooting or budbreak. Chemical names used: (2-chloroethyl)-phosphonic acid (ethephon); indole butyric acid (IBA); N,N'-bis(3-aminopropyl) -l,4-buanediamine (spermine).
Softwood shoots of apple (Malus domestica Borkh.) rootstocks M.9 and MM.106 were banded with Velcro for up to 20 days before cuttings were propagated. Percent rooting and the number of roots per cutting were significantly improved by banding for 10 to 20 days, with and without IBA application. As the duration of stem banding increased from 0 to 20 days, percent rooting and the number of roots of both M.9 and MM.106 cuttings increased linearly or curvilinearly. Stem banding also stimulated budbreak of cuttings. In M.9, banding resulted in a higher survival rate and increased new shoot growth of transplanted cuttings after 4 months. Percent budbreak and new shoot growth were highly correlated with the number of roots per cutting in both cultivars. The effects of stem banding on budbreak and subsequent growth of the cuttings were largely due to the enhanced rooting of cuttings. Chemical names used: 1H-indole3-butyric acid (IBA).
Single-node `Royalty' rose (Rosa hybrida L.) cuttings were used to examine the relationship between adventitious root formation, budbreak, and ethylene synthesis following IBA treatment. IBA was applied as a lo-second basal quick dip before rooting, and AIB, GA3, STS, and ethephon were applied either as basal dips or foliar sprays. IBA application increased rooting and inhibited budbreak of cuttings. IBA 2 600 mg·liter-1 greatly inhibited budbreak during 4 weeks of rooting. IBA treatment stimulated ethylene synthesis, which was inversely correlated with budbreak of cuttings. Ethephon also significantly inhibited budbreak. Budbreak of rose cuttings was completely prevented by repeated ethephon sprays used to maintain high endogenous ethylene levels during the first 10 days. Treatment with STS, an ethylene-action inhibitor, improved budbreak. The inhibition of budbreak by IBA treatment resulted primarily from elevated ethylene levels. Root initiation and root elongation of cuttings initially inhibited budbreak, but later promoted budbreak. Chemical names used: indole-3-butyric acid (IBA); gibberellic acid (GA3); silver thiosulfate (STS); AIB, aminoisobutyric acid (AIB); (2-chloroethyl)-phosphoric acid (ethephon).