Mist propagation of peach and almond × peach hybrids

Several factors contributing to the successful rooting of stem cuttings of four peach clones and one almond × peach hybrid under intermittent mist were tested. With the almond × peach cross, leaf-bud cuttings were also tested.Severe cutting back of adult peach mother trees in winter favoured rooting of the cuttings, but less severe cutting back induced maximum roots per cutting.For short periods vermiculite was found to be a suitable medium. Sand alone or mixed with vermiculite or gravel gave poor results. Gravel alone or mixed with vermiculite was intermediate. For growing the rooted cuttings for a longer period, a mixture of perlite and peat was very suitable.A period of illumination of 3 h starting at midnight with incandescent light improved rooting of peach cuttings in August and October, but not in June.With cuttings obtained from old fruit-bearing peach trees highest rooting rates were obtained in July, but best root development occurred when rooting was carried out in October. In July rooting rate of basal cuttings was much higher than that of terminal ones. Success with leaf-bud cuttings (including a small branch piece) obtained from young mother trees of the almond × peach hybrid was only achieved at the end of May or in June.Dipping the base of peach cuttings in water before rooting was of advantage with one cultivar rooted in September, but of no advantage with another cultivar rooted in June.When the base of stem cuttings was dipped for a prolonged period in IBA solutions of various concentrations, highest rooting rates were obtained with 25–50 ppm IBA for peaches and with 200 ppm for the almond × peach hybrid. The addition of Phygon XL to this solution was of some advantage for peach cuttings. The concentration inducing maximum root development was higher than that required for maximum rooting and callusing. The optimal IBA concentration for rooting of almond × peach leaf-bud cuttings was 100 ppm.Penetration of the IBA into the leaf-bud cuttings reached a maximum 45 min a after floating them on a 100 ppm solution.Transplanting cuttings which had been rooted under mist was somewhat difficult; however, high rates of survival were obtained with cuttings planted in September which had developed a good root system.