The article highlights results of research over simulative apomixes in pear and its utilization for obtaining haploids and homozygote diploids. It has been established that over 50% pear varieties with failed remote hybridization are capable of generating seeds of apomictic origin producing diploid plants. Genotypes displaying maximal inclination to apomixes have been singled out. Apomictic pear seedlings obtained from foreign pollination within the limits of the same combination are inherent in profound morphological diversity. Fruit-bearing apomicts originated from one and the same maternal plant differ to the same extent as hybrid seedlings of the same family. Genetic markers have enabled to establish that these are embryo sacs in which meiosis has completed that give rise to apomictic seeds. In vitro method as used for the purpose of increasing apomictic plants output has been illustrated. The greatest induction of apomictic shoots in vitro has been reached by alternation of BAP cytokinin at concentration of 1mg/l and 2 mg/l on the background of GA3 amounting to 1,5 mg/l. Grafting with shoots in vitro on non-sterile rootstocks of pear (Pyrus communis) has increased the output of plants up to 80%. A cytological assessment of 9 apomictic samples is provided. The cytological analysis of samples of apomictic forms has certified the presence of simulative haploid parthenogenesis in pear.

The study results for many years (1972- 2006) of pear gene pool in the All- Russian Research Institute of Horticultural Breeding are given. The cultivars and selections have been singled out for wide dissemination and use in breeding.

To analyse the modern classification and nomenclature of species of pome fruit crops which varieties are listed in the State Register of Plants Varieties Suitable for Dissemination in Ukraine, and improve terminological system of the Ukrainian names of both species and garden crops. Results. Fruit cultivars and most apple clonal rootstocks belong to Malus pumila, and ornamental cultivars belong to Malus gloriosa. The most common scientific name of the cultivated apple, especially among horticulturists, is Malus domestica, although according to the principle of priority the name Malus pumila should have the advantage. As far as Nomenclature Committee for Vascular Plants has rejected the proposal to conserve the name Malus domestica, Malus pumila is correct name for the cultivated apple. The use of synonymic name Malus domestica should be avoided in both scientific and scientific-popular papers for stability of nomenclature. Pear cultivars listed in the State Register of Plants Varieties Suitable for Dissemination in Ukraine are presented by Pyrus communis, and pear rootstocks – by Cydonia oblonga. Fruit cultivars of the latter belong to separate fruit crop named quince. An apple-quince hybrid was registered as universal clonal rootstock for pome fruit crops. The State Register of Plants Varieties Suitable for Dissemination in Ukraine also contains nonconventional fruit crops such as Chaenomeles and hawthorn that consist of some species and nothospecies. Conclusions. In scientific publications one should stop the use of synonymic name Malus domestica in favour of the correct name for cultivated apple Malus pumila. Apple, pears and Chaenomeles cultivars listed in the State Register of Plants Varieties Suitable for Dissemination in Ukraine have a complex multispecies origin whereas quince, hawthorn and pear roostock cultivars systematically are monospecies. A universal roootstock of pome fruit crops is Cydolus, or apple-quince, that resulted from interspecies hybridization between quince and apple. Refusal Refuse to use obsolete names of fruit plants species will promote harmonization of professional language.

The development features of four samples of apomictic plants during micropropagation are presented. These plants have been derived from embryos after pear pollination with the pollen of Chaenomeles japanica at 55 and 70 days of their development. Different responses of samples on the tested concentration of cytokinin (6BAP) and its combination with gibberell acid are shown. Tendency of increasing of the coefficient of the reproduction of separate numbers of apomictic plants has been noted under changing of BAP concentration from 1 mg/l to 2 mg/l or BAP combination with GA3. For the purpose of optimization of the stage of conglomeration forming (buds and shoots) BAP concentration 1 and 2 mg/l should be alternated in a passage on the background of GA3 1,5 mg/l. For the first time the origin of apomictic plant roots during rhizogenesis has been retraced and the anatomical structure of roots in conditions in vitro has been studied. Root formation in vitro occurs in internal tissues of a shoot. Roots of apomictic plants formed in vitro are primary as in plants developed in vivo.