In Vitro Propagation of Poplar and Aspen

Abstract

Poplar and aspen belong to the genus Populus, and family Salicaceae. They are dioecious, with male and female flowers (catkins) occurring on separate trees. The diploid chromosome number in poplar and aspen is 2n = 38. The genus Populus is comprised of five sections, consisting of more than 30 species widely distributed in the Northern Hemisphere (20, 22). The five sections of the genus Populus are: 1) Turanga, consisting of a single species, P. euphratica Oliv., which is native to western and Central Asia, as well as North and Central Africa; 2) Leucoides, contains four species, none of which are of economic importance; 3) Leuce, a large group further divided into two subsections: Albidae, consisting of white poplars, P. alba L. and P. monticola T. Brand, and Trepidae, consisting of aspens (several species); 4) Tacamahaca, collectively known as balsam poplars, is the largest section of the genus, and contains several species of economic importance; and 5) Aigeiros, the “true poplars”, to which more than 90% of the cultivated poplars (mainly cottonwoods and black poplars) of the world belong. Three main species are included in the section Aigeiros: eastern cottonwood (P. deltoides Marsh.), distributed over most of the United States of America and southern Canada; arid-zone cottonwood (P. fremontii Wats.), distributed over south-western portion of the United States; and black poplar (P. nigra L.), a native of Eurasia.