On the basis of diversity of wild types of the genus Prunus L. (P. cerasifera, P. armeniaca, P. persica, P. fruticosa, P. lannesiana, P. maackii, P. tomentosa, P. pumila, and P. incana) in the collection of the Krymsk Experiment Breeding Station, highly adaptive, medium or weak vigour clonal rootstocks for stone fruit crops with good compatibility with grafted cultivars were selected: for plum, apricot and peach - Kuban 86, VVA-1, Evrika 99, Zarevo (Glow), Alab 1, Speaker, Best, VSV-1; and for sweet cherries and sour cherries - L-2, LC-52, VSL-1, VSL-2, and RVL-9. Part of the rootstocks were tested and successfully used in different parts of Russia and some near and far countries. The applied integration of tissue culture in vitro in the selection process at the station considerably promoted the rapid introduction of new rootstocks into world production. Technologies were developed for microclonal reproduction, and green and woody cuttings. The revealed light rooting of woody cuttings of stocks Kuban 86, Evrika 99, Zarevo, Best, VSL-1, RVL-9 (50-80%) allowed to develop technology for growing of young plants on these rootstocks directly in the first field of the nursery.
, remaining taxa have been found on selected continents ( Table 1 ). Perhaps the most thorough research was carried out in Africa ( Gibbons, 1981 ; Boomker, 1982 ; Boomker & Taylor, 2004 ) but many regions of the world have not been sufficiently explored. In Europe, only C. curticei, C. oncophora, C. pectinata , and C. punctata represent the valid taxa. Due to polymorphism and/or inter-specieshybridization which may occur within the members of the genus ( Wyrobisz et al., 2016 ) species boundaries of currently deemed valid Cooperia spp. may be rather unclear. For