by
W. Lahera, A. Alvarez and S. Gámez
Forest Research Institute
Calle 174 # 1723
Pto Siboney, Municipio Playa
Ciudad de La Habana, Cuba
Cedrela odorata L. is one of the most important timber-producing species in Cuba. It is found in the archipelago of the Antilles and, on the mainland, along the Gulf of Mexico from just south of the town of Tampico to the Yucatan Peninsula; and from the State of Sinaloa to the State of Guerrero on the Pacific side of Mexico. It is also probable that the species is native to some countries in the Central American region and in the northern parts of South America (Betancourt 1987).
At the 5th Session of the FAO Panel of Experts on Forest Gene Resources held in Rome in 1981, Cedrela odorata was included in the list of priority species in need of attention (FAO 1984). This listing underlined the importance of early action in the conservation and exploration of genetic variation of the species and in its reproduction and sustained use. The recommendations of the FAO Panel of Experts were in line with those made by Pennington (1968) and Lamb (1969), who stressed that this species, of great commercial value due to its superior timber qualities had, over the years, become increasingly scarce due to over-exploitation.
A genetic improvement programme in Cedrela odorata was started in Cuba in 1973. A clone bank was established in 1975 in Guisa (Granma), at an altitude of 260 m a.s.l.; it contains genetic material of more than 250 plus trees from throughout the country. This is likely to be the largest existing collection of this species; it is, indisputably, the largest collection of genetic materials maintained within its natural distribution range. Within the framework of the programme, four progeny trials and a clonal seed orchard were also established between 1986 and 1990. The seed orchard is approximately 10 ha in extent.
One of the parameters frequently studied in clonal material of species of economic interest is repeatability, which gives an indication of levels of broad sense heritability (total genetic variation plus environmental effects) (see e.g. Becker 1967, Gálvez 1980).
Based on studies of 100 of the clones contained in the clone bank in Guisa, repeatibility values were estimated for height and diameter at 1.3m (DBH), at age 14, including between 3 and 5 grafts per clone in the assessment. The repeatability value (broad sense heritability) for height was found to be 0.85; and that for diameter 0.62. This indicates that these two characteristics are under medium to strong genetic control and that acceptable genetic gains can be expected from a genetic improvement programme focussed on them.
Work in Cedrela odorata has largely been limited, to date, to provenance work (see e.g. Anon 1981–82), research on vegetative propagation (for work carried out in Colombia, Costa Rica and Venezuela, see Guevara 1988; Díaz et al 1992; and Quijada and Gutiérrez 1971), and selection for resistance to shoot borer (see e.g. Newton 1990). It is hoped that the present report is of interest to other institutes dealing with the species, as it reports on aspects of basic importance for a tree improvement programme which to our knowledge have not earlier been documented.
REFERENCES
Anon. (1981–82). Annual Report, Unit of Tropical Silviculture. Commonwealth Forestry Institute, Oxford (U.K.):p.4.
Betancourt, A. (1987). Silvicultura Especial de Arboles Maderables Tropicales. La Habana, Cuba. Edit. Ctfco.-Tecn. 427pp.
Díaz M., E.R.A., Salazar, R. y Mésen, F. (1992). Enraizamiento de estacas juveniles de Cedrela odorata L. Silvoenergía No 51, junio de 1992. CATIE, Turrialba (Costa Rica)
FAO (1984). Informe de la Quinta Reunión del Cuadro del Expertos de la FAO en Recursos Genéticos Forestales. FO:FGR/5/Rep. FAO, Roma. 107pp.
Guevara M., G. (1988). Experiencias Colombianas con Cedro (Cedrela odorata L.). Corporación Nacional de Investigación y Fomento Forestal, CONIF. Serie Documentación No 12 (Noviembre de 1988). Bogotá, Colombia. 86pp.
Lamb, A.F. (1969). Especies Maderables de Crecimiento Rápido en la Tierra Baja Tropical. En: Bol. Inst. Forestal Latinomericana 30–31/15–54. (Mérida, Venezuela).
Newton, A. (1990). Selección por resistencia al perforador de la Meliáceas. Noticiero: Mejoramiento Genético y Semillas Forestales para America Central No5, Agosto 1990, pp.4–7. CATIE, Turrialba (Costa Rica).
Betancourt, A. (1987). Silvicultura Especial de Arboles Maderables Tropicales. La Habana, Cuba. Edit. Ctfco.-Tecn. 427pp.
Pennington, T.D. (1968). Manual para la Identificación de Campo de los Principales Arboles Forestales Tropicales de México. Instituto Nacional Forestal, Mexico. 413pp.
Quijada, R.M. and Gutiérrez, V. (1971). Estudio sobre la Propagación Vegetativa de Especies Forestales Venezolanas. Revista Forestal Venezolana 14(21):43–56.
Forest Genetic Resources No. 22. FAO, Rome (1994)
Manuscript received July 1994. Original Spanish.
