RELATIONSHIP BETWEEN PARENTAL CHROMOSOMIC CONTRIBUTION AND NUCLEAR-DNA CONTENT IN THE COFFEE INTERSPECIFIC HYBRID C-PSEUDOZANGUEBARIAE X C-LIBERICA VAR DEWEVREI

F-1 hybrids were obtained between two coffee species with the same chr omosome number (2n = 22) but with different nuclear DNA contents CC. p seudozanguebariae (PSE) 2C = 1.13 pg and [C. liberica var 'dewevrei' ( DEW) 2C = 1.42 pg]. G2 hybrids were obtained by open-pollination of th e F-1 hybrids. Genomic in situ hybridisation (GISH) and flow cytometry were used on six F-1 hybrids and seven G2 hybrids to determine their parental chromosomic contribution and their nuclear DNA content (qDNA) , respectively. GISH efficiently identified chromosomes from both spec ies. F-1 hybrids had a qDNA intermediate between that of the parental species and contained the expected 11 chromosomes from each species. T here was a linear relationship between the number of PSE chromosomes a nd the nuclear DNA content, which indicates that flow cytometry can be used to give a rough estimate of the parental chromosomic contributio n in G2 hybrids.