Propagation of Ornamental Plants
9(4): 181-184, 2009
SHOOT FORCING AND ROOTING OF BETULA NIGRA L.
Laurie J. George and John E. Preece*
Department of Plant, Soil and Agricultural Systems, MC 4415, Southern Illinois University, Carbondale, IL 62901-4415, USA, *Fax: + 1 618 453 7457, *E-mail: jpreece@siu.edu
Abstract
Betula nigra trees (6-12 years-old) were cut into twelve 50-cm long segments from the ground up to study the effects of position on production and rooting of forced softwood cuttings. Immediately after cutting, the segments were placed horizontally in flats containing perlite so the one third of the stem in contact with the medium was buried. Shoot forcing was in a greenhouse and under intermittent mist with a natural photoperiod. The forced softwood shoots were then harvested as cuttings and treated with 0.3% IBA in talc for rooting under fog. Number of cuttings produced and rooted was highest from the lowest two segments (lowest 1 m of the tree) and decreased in a quadratic manner as position of origin along the main stem was farther from the ground. Mean number of roots on cuttings that formed adventitious roots decreased linearly as position of origin of the stem was progressively farther from the ground. Stem segments began producing the first rootable cuttings five weeks after forcing began and continued for 16 weeks and shoot production from the combined forced 6 m of stem per tree followed a quadratic curve and peaked 4-10 weeks after the first cuttings were harvested.
Key words: clone, cutting, epicormic shoots, propagation, River birch, tree
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