RECENT CONCEPTIONS ABOUT THE POSSIBLE ORIGIN OF THE CULTIVARS AND ROOTSTOCKS OF MALUS DOMESTICA BORKH.
The findings of recent, partly compiled, papers mainly from Russia (JUSPEPCUK 1939, LANGENFELD 1971, PONOMARENKO 1975, 1977) were as follows, that M.pumila as origin species should are substitute because of inexact definition. For these classification studies for distinctive features are used: a) the position of leaves in the buds, b) the behaviour of calyx (deciduous or persistent), c) the occurrence of stone cells in the fruit flesh, and d) the leaf character (lobed or unlobed).
Because of great variation of the above features, of general self-sterility and of frequent hybridization, in this genus, on principle, founded classifications are highly doubtful.
In spite of these facts, there is much to be said, that within the section Malus the series Pumiliae can be qualified, to which following three species are to place:
- M.sylvestris MILLER incl.M.praecox (PALL;) BORKH.
- M.orientalis UGLITZKICH and
- M.sieversii (LEDEB.) ROEMER incl.M.niedzwetzkyana DIECK
- M.domestica might be a hybrid-complex, who chiefly derived itself from
- M.orientalis and M.sieversii, however hardly or never at all from
- M. sylvestris, althought the last-called species is endemic in Europe.
The cultivated species M.paradisiaca MED. and M.sasyphylla BORKH. var. tomentosa GAMS, originated by some inter-or intraspecific crossings, are considered either as forrunner of M.dom. or arised from it.
Probably the rootstocks M1 and M9 are descendant from M.paradisiaca, M4 and M11, against this, such ones from M.dom.var.tomentosa.