Somaclonal Variation in Populus Hybrids Regenerated from Protoplast Culture

Abstract

Protoclones were regenerated from the poplar hybrid NC5339 (Populus alba × P. grandidentata ‘Crandon’). Morphologic variation primarily in leaf characteristics has been observed in four vegetative generations under both greenhouse and field conditions. Three variant tree types have been identified: (1) Normal growth rate with long leaves that have reduced pubescence on the underside of the leaves. Leaves show sectoring of pubescence levels. (2) Slower growing with thick, dark green, heavily pubescent leaves in highly convoluted, brittle leaves. (3) Dwarf fast-growing tree with ovate, pale green leaves and a tendency for heavy branching. Leaves show sectoring of pubescence levels. Possible explanations for the variation observed are offered.