Distinguishing Apple Clones and Cultivars by Surface Morphology and Pollen Physiology

Pollen grains of 31 cultivars of apple ( Malus domestica Borkh.), including 13 “standard” and “spur” clones, were examined using scanning electron microscopy (SEM) and some physiological characters (germination, pollen tube length, and viability) for identification purposes. Sizes and shape of pollen were quite uniform within a given cultivar. The differences in the exine pattern may help for the identification of some cultivar, or of groups of genetically close cultivars. Size and number of the pits made the separation of some cultivars from others possible while slight differences in the ridge pattern and the physiological characters (viability and germination) were useful traits to discriminate standard from spur types within a given polyclonal cultivar.