STUDIES IN THE HETEROSIS OF HYBRID STRAWBERRY PLANTS AT THE EARLY STAGES OF DEVELOPMENT

Abstract

The article comprises the results of the comparative studies of the hybrids froili the reciprocal crosses of different strains of one species of strawberry (Fragaria vesca L.) and of their parental forms. The object of these studies was the manifestation of heterosis at the early stages of the development of the hybrid plants under different conditions of cultivation. It has been shown that the potential (genetic) heterosis of hybrid plants has different values (as determined by the comparison with the parental plants) at different stages of their ontogeny (the phasic development of heterosis). The environmental conditions favourable for the development of the hybrid plants stimulate a more conspicuous manifestation of heterosis. Distinct differences were observed between the reciprocal hybrids in the energy of germination and in the type of differentiation of the first leaves This suggests that the early ontogenetic stages of the hybrid strawberry are determined not only by the genotype of the hybrid embryo, but also by the cytoplasmic factors of the egg-cell.