Anatomical and physiological aspects of propagation of two low-chill peach cultivars by stem cuttings

Rooting abilities of stem cuttings of two low-chill peach cultivars, Flordabelle and Flordagold, were studied in 1988/1989 seasons: Jan., June, Aug. and Dec. Three wood positions of the shoot, basal, intermediate and terminal, were used as well as two auxin types, IBA and NAA, at concentrations of 0, 1000, 2000, 3000 and 4000 ppm. The cuttings were microscopically examined during various stages of adventitious roots development to determine their origin and detect barriers to root emergence. Rooted ability of sprouted nodal cuttings was also studied at 50% leafing out stage using IBA and NAA at 0, 750, 1000, 1500, and 2000 ppm. Results showed that Flordabell cuttings gave highest rooting percentage of 100% with basal and intermediate at 1000 ppm IBA and 96.7% with terminal at 1000 ppm IBA in Aug., 83.3% with basal cuttings at 1000 ppm IBA in June, and 60% with intermediate treated with IBA at 1000 ppm in Dec.. In addition, highest average root number per rooted cutting was 19 with intermediate cuttings at 4000 ppm IBA in Jan.; 18.7 with basal cuttings at 1000 ppm IBA in Aug., and 14 with terminal at 2000 ppm IBA in June. On the other hand, Flordagold cuttings gave highest rooting percentage of 88.9% with basal at 1000 ppm IBA in June; 88% with terminal at 3000 ppm in Jan.; 83.3% with intermediate at 1000 ppm IBA in Aug. However, highest average root number per rooted cuttings of 25.3 roots was obtained with basal cuttings at 3000 ppm IBA in Jan.; 12.8 with basal at 3000 or 4000 ppm IBA in Aug.; 11 roots with intermediate cuttings at 3000 ppm IBA in June. On the other hand, combined percent of callusing and rooting with many combination treatments reached 100% with the two cultivars in all collecting dates. The sprouted nodal cuttings showed that Flordabelle cuttings gave 27.8% rooting at 750 ppm IBA. The anatomical studies revealed three possible origins for adventitious roots formation. These are the cambium, phloem and cortex. Sclerenchymatous ring in Flordabelle and Flordagold peach stem cuttings was not found to restrict emergence of adventitious roots