© 2003 Heron Publishing—Victoria, Canada
Somaclonal variation in Coffea arabica: effects of genotype and embryogenic cell suspension age on frequency and phenotype of variants
H. Etienne (1, 2, 3) and B. Bertrand (2, 4)
1. Laboratorio de Biotecnología, CATIE, Apartado 11, 7170 Turrialba, Costa Rica / 2. Centre de Coopération Internationale en Recherche Agronomique pour le Développement-Cultures Pérennes (CIRAD-CP), Genetrop,
IRD, 911, Avenue Agropolis, BP 5045, 34032 Montpellier, France / 3. Author to whom correspondence should be addressed (herve.etienne@cirad.fr) / 4. Instituto Internacional de Cooperacion Agricola (PROMECAFE/IICA), Apartado 55, 2200 San José, Costa Rica / Received April 5, 2002; accepted October 12, 2002; published online March 17, 2003
Summary
We determined how age of embryogenic cell suspensions affects somaclonal variation in five F1 hybrids of Coffea arabica L. Batches of plants were produced either directly from embryogenic callus, or after 3, 6, 9 and 12 months of embryogenic
cell suspension culture. Seven phenotypic variants were characterized. Based on vigor and productivity of the regenerated
plants, we classified the variants in order of increasing severity of physiological disorders as: Juvenile leaf color, Giant,
Dwarf, Thick leaf (Bullata), Variegata, Angustifolia, and Multi-stem. The Dwarf, Angustifolia and Multi-stem variants were
the most frequent among the regenerated plants (1.4, 4.8 and 2.9%, respectively). The frequency (f) of variants increased exponentially with the age (t) of the embryogenic suspension, in accordance with the function f = 0.99e0.267t. For all genotypes, somaclonal variation was low (1.3%) in plants produced from embryogenic callus or 3-month-old cell suspensions
and increased in frequency with increasing suspension age (6, 10 and 25% in plants produced from cell suspensions aged 6,
9 and 12 months, respectively). Large differences in somaclonal variation among genotypes were found only in plants produced
from 12-month-old cell suspensions. For two genotypes, the oldest suspensions produced a majority of somaclonal variants (80–90%),
whereas somaclonal variation ranged between 8 and 18% in the other genotypes. Cell suspension age and genotype also affected
the type of variant produced. The severity of somaclonal variations increased with cell suspension age. For all genotypes
combined, the Angustifolia variant was the most common. The other somaclonal variations were specific to certain genotypes
or distributed randomly among the genotypes.
Keywords:
coffee, field trial, somatic embryogenesis.
