Heterochromatin and rDNA sites in Coffea L. chromosomes revealed by FISH and CMA/DAPI II:: C-canephora cv. Apoata, C-salvatrix and C-sessiliflora

Cytogenetic studies in coffee species present a lack of information caused by some cytological characteristics, such as small chromosomes, symmetric karyotypes and the remarkable genetic homogeneity presented by the genus Coffea. Cytomolecular techniques based on in situ hybridization brought up new possibilities to improve the knowledge of cytogenetic characters and cytological processes involved in speciation of taxa with these cytological features. In the present work we analyzed one cultivar (C canephora cv. Apoata) and two wild diploid species (C salvatrix and C. sessiliflora) of the Coffee Germplasm Bank of IAC attempting to cytogenetic characterization. Chromosome banding with fluorochromes DAPI and CMA(3) and in situ hybridization with specific probes for rDNA sites 18S-5.8S-26S (probe pTa71) and 5S (probe pScT7) were carried out. For C salvatrix and C sessiliflora the CMA3 positive bands agreed with the in situ hybridized rDNA sites in number, size and position. The little variation in number and length of the rDNA sites between species of coffee is discussed.