2014 Volume 79 Issue 4 Pages 567-573
The objective of this study was to evaluate the genetic relationship between five Vasconcellea species (V. cauliflora, V. goudotiana, V. quercifolia, V. monoica, and V. cundinamarcensis) and Carica papaya based on their chromosome features. To do that, five metaphase plates showing well spread and condensed chromosomes were used for the chromosome measurements: the absolute chromosome length (CL) and the lengths of the long (LA) and short (SA) arms. Further, we estimated the ratio between the arms (r), the centromeric index (CI), and the total length of haploid set (TLH). The Total Form index (TF%), the Rec, and the SYi were estimated for symmetry/asymmetry of the karyotype. Most species show karyotype formulae of nine pairs of metacentric chromosomes (9m) except for V. goudotiana, which has five pairs of metacentric chromosomes and four pairs of sub-metacentric chromosomes (5m+4sm). V. goudotiana had the longest total length of haploid set, whereas V. quercifolia showed the shortest one. Based on the estimates of symmetry/asymmetry indexes, four species have symmetric karyotype; moreover, V. goudotiana has asymmetric karyotype because it showed the lowest values of Syi and TF% index. The similarity matrix of five parameters for the six species was employed and based on the dendogram four clusters were formed; the first included C. papaya and V. cundinamarcensis, the second cluster was formed by V. monoica and V. cauliflora, the third by V. quercifolia and fourth by V. goudotiana. So, based on chromosome features V. cundinamarcensis, V. cauliflora, and V. monoica are closer to papaya than V. goudotiana.
