Résumé
F1 hybrids were obtained between two coffee species with the same chromosome number (2n = 22) but with different nuclear DNA contents (C. pseudozanguebariae (PSE) 2C = 1.13 pg and C. liberica dewevrei (DEW) 2C = 1.42 pg). Hybrids of second generation were obtained by open-pollination of the F1 hybrids. Genomic in situ hybridisation (GISH) and flow cytometry were used on 6 F1 hybrids and 7 hybrids of second generation in order to determine their parental chromosomic contribution and their nuclear DNA content (qDNA), respectively. GISH efficiently identified chromosomes from both species. F1 hybrids had qDNA intermediate between the parental species and contained 11 chromosomes from each species as expected. There was a linear relationship between the number of PSE chromosomes and the nuclear DNA content. This result allows flow cytometry to give a rough estimate of the parental chromosomic contribution in coffee interspecific hybrids. (Texte intégral)