Morphological, anatomical and cytological characteristics of spontaneous hybrid Pyrus x myloslavensis

Pyrus ×myloslavensis is a hybrid with intermediate characteristics of leaves and fruits inherited from its parental species P. salicifolia and P. communis. The aim of this study was to determine whether these intermediate nature of this taxon would be visible in the pollen and seed anatomy and morphology. In addition, the authors evaluated self-compatibility and crossability based on the observation of pollen tube growth. The investigations were carried out using light, fluorescence and electron microscopies and flow cytometer. Based on pollen and seed morphology the current study confirmed a hybrid origin of the investigated taxon. Especially, pollen grains had most features similar to both parental species. In respect to epidermal micromorphology, the seeds of P. ×myloslaviensis were like P. salicifolia, but anatomical structure of the seed coat of the hybrid was more consistent with P. communis. The data obtained from the current experiment showed that P. ×myloslavensis was self-incompatible and cross-compatible only with one of four tested P. communis cultivars (‘Conference’) and with P. salicifolia. In turn, the average genome size of the hybrid was smaller than putative parents.