Polymorphism in cherry plum (<i>Prunus cerasifera</i>) and its significance for stone crop breeding

A gene pool of cherry plum (Prunus cerasifera Ehrh.) numbering over 1000 accessions including wild forms and released cultivars of various origins has been gathered at the Krymsk Experiment Breeding Station, a branch of VIR. The study of the morphological diversity of cherry plum, or myrobalan plum, made it possible to clarify its position within the system of the genus Prunus L., and to propose an intraspecific system composed of three subspecies: Prunus cerasifera subsp. cerasifera – the typical cherry plum, P. cerasifera subsp. orientalis (M. Pop.) Erem. et Garcov. – the oriental cherry plum, and P. cerasifera subsp. macrocarpa Erem. et Garcov. – the large-fruited cherry plum with the following several varieties: Armenian (P. cerasifera subsp. macrocarpa var. nairica (Koval.) Erem. et Garkov.), Georgian (var. georgica (Erem.) Erem. et Garcov.), Iranian (subsp. macrocarpa var. iranica (Koval.) Erem. et Garcov), Pontic (subsp. macrocarpa var. pontica (Koval.) Erem. et Garcov.), Tauric (subsp. macrocarpa var. taurica (Kost.) Erem. et Garcov.), and the red-leaved cherry plum (Pissard plum) (subsp. macrocarpa var. pissardii (Carriere) Koehne).The most important role of interspecific hybridization involving the species P. cerasifera is in the origin of a number of Prunus L. species, including domestic plum P. domestica L., Fenzl’s almond P. fenzliana Fritsch, and black apricot P. dasycarpa Ehrh., has been established.The cherry plum gene pool had been found to contain donors of a number of traits of importance for breeding, which were used to create an assortment of Russian plum (Prunus × rossica Erem., hybrid myrobalan plum) cultivars and clonal rootstocks of stone fruit crops. Among them, the Russian plum ‘Globus’, ‘Kubanskaya Kometa’, ‘Gek’, ‘Kolonnovidnaya’, ‘Iyulskaya Roza’, and clonal rootstocks ‘Kuban 86’, ‘VVA 1’, ‘Evrika 99’, ‘Best’, ‘Zarevo’ have been regionally adapted and got a wide distribution.An outstanding general combining ability was demonstrated by cherry plum cvs. ‘Pionerka’, ‘Purpurovaya’, ‘Otlichtnitsa’, ‘Ashtarakskaya 2’ and ‘Tsiteli Drosha’, which were used in breeding a number of cherry plum cultivars at the Krymsk EBS, e.g. cherry plums ‘Neberdzhaevskaya Rannyaya’, ‘Kremen’, Russian plum ‘Kubanskaya Kometa’, ‘Iyulskaya Roza’, ‘Naydena’, ‘Gek’, ‘Podarok Sad-Gigantu’, etc.Most effective was the hybridization of Crimean, Armenian and Georgian cherry plum cultivars with the Chinese plum (Prunus salicina Lindl.) ‘Burbank’, ‘Gigant’, and ‘Skoroplodnaya’. As clonal rootstocks, the hybrids of myrobalan plum with peach (‘Kuban 86’ and ‘Fortuna’ rootstocks), with cherry plum ‘Sapa’ (‘Evrika 99’ and ‘Spiker’ rootstocks), as well as with low micro-cherry (rootstock ‘Best’) and Louiseania ulmifolia (Franch.) Pachom. (rootstock ‘Upriamets’) turned out to be very valuable.