© 2004 Heron Publishing—Victoria, Canada
Influence of nutrient application rate on growth and rooting potential of the West African hardwood Triplochiton scleroxylon
J. McP. Dick (1, 2), R. R. B. Leakey (1, 3), C. McBeath (1), F. Harvey (1), R. I. Smith (1) and C. Woods (4)
1. Centre for Ecology and Hydrology, Bush Estate, Penicuik, EH26 0QB, Scotland, U.K. / 2. Author to whom correspondence should be addressed (jand@ceh.ac.uk) / 3. Agroforestry and Novel Crops Unit, School of Tropical Biology, James Cook University, P.O. Box 6811, Cairns, QLD 4870, Australia / 4. Centre for Ecology and Hydrology, Merlewood, Grange-over-Sands, Cumbria LA11 6JU, U.K. / Received December 18, 2002; accepted June 14, 2003; published online December 1, 2003
Summary
Effects of stock plant nutrition on growth and subsequent rooting of leafy stem cuttings of the commercially important west
African tree Triplochiton scleroxylon K. Schum. were investigated to identify the primary morphological variables influencing adventitious root formation. Potted
plants were watered as required with one of four balanced nutrient solutions (0, 15, 63 or 125 mg N l–1). Increasing the nutrient supply to stock plants increased growth rate and rate of adventitious root production of subsequently
harvested cuttings, but an optimum nutrient regime was not identified. Rooting percentage increased from 27% in cuttings harvested
from stock plants receiving a low nutrient supply to 64% for cuttings harvested from stock plants receiving eight times the
amount of nutrients extractable from plants under typical field conditions in West Africa. The ability of a cutting to retain
its leaf during propagation and the length of the cutting were the primary measured characteristics associated with rooting
and accounted for 43% of the variance fitted in the model. The length of the new shoot, total leaf area and within-shoot position
(node position) were also significantly associated with rooting. After these characteristics were fitted to the model, the
genetic origin (clone) was not statistically significant. We conclude that genetic variation in rooting potential is mediated
through variations in morphological and physiological traits, rather than through genetic variation in cell differentiation
or related aspects of root initiation.
Keywords:
genetic variation, photosynthesis, vegetative propagation.
