Shoot Selection and the Rooting and Field Performance of Tropical Pine Cuttings

Abstract

Several morphological features were significantly related to the rooting response, and subsequent field performance as rooted cuttings, of shoots collected from hedged stool plants of an F1 hybrid between Pinus caribaea var. hondurensis and P. tecunumanii. Results indicate that it will be possible to manipulate rooting and field performance by shoot selection at the time of harvest of cuttings. The cutting which best meets the objective of maximum rooting without loss of field performance is the terminal segment from a shoot over 30 cm in length, with an actively growing juvenile bud, primary needles in excess of 25 mm, secondary needles present but less than 10 mm in length, and basal diameter over 2 mm. The use of second and third segments of shoots, where these have the appropriate features, would permit greater utilization of material with only a minor decrease in rooting. Primary needle length was the best morphological predictor of both rooting and field height growth. Significant positive genetic correlations suggest that within-family selection for primary needle length will involve selection for clones which root well and which display good height growth in the field, perhaps as a result of slower stool plant aging. For. Sci. 38(1):95-101.