Effect of Length of Cuttings, Substrate pH and Mineral Nutrition on Rooting of Pyrus communis Cultivars

摘要

Cultivars of the genus Pyrus, commonly known as pear, are generally propagated, by budding on root-stocks,, Pyrus cvs. on their own roots may overcome the problems of Pyrus cvs, on the often used quince rootstock in calcareous soils and the problem ofpoor winter hardiness. Because small cuttings are difficult to root, at the first time investigations on propagation of long cuttings (100 cm) of Pyrus culti-vars were initiated. The influence of pH and application of a slow release fertilizer on rooting in Pyrus communis cv.'Williams Christ' long cuttings was investigated. The highest rooting percentage was observed at a pH of 5.7 in the substrate, while application of 2 kg m~(-3) Plantacote Mix 4M~R was optimal for rooting. The pH of the substrate affected the root number and the length of the roots. Use of Plantacote Mix 4M~R did not improve root length. The pH of the substrate and the use of slow release fertilizer influenced the length of side branches. The influence of apical and basal positionand length of cuttings on rooting proper ties of Pyrus communis cv. 'Conference' was studied in an unheated greenhouse experimental set-up. The length of cuttings did not significantly affect rooting percentage. Cuttings taken from the basal parts had higher rooting than cuttings from apical parts. Long cuttings tended to have the highest number and length of side branches per cutting. Most of the rooted long cuttings develop flower buds before transplanting in the field. Loss of rooted cuttings due topoor overwintering is a common problem in many nurseries. The effect of two overwintering methods on subsequent field establishment was studied. Field establishment of rooted Pyrus cv. cuttings was more successful after leaving the cuttings in an unheated greenhouse in winter and planting out in spring as compared to field planting in autumn.