Inbreeding depression in crosses of coerulea clones of Walkers Cattleya (Cattleya walkeriana Gardner)

Orchids are among the most beautiful flowers and endangered due to habitat destruction and over-collection. Cattleya walkeriana is one of the most beautiful flowers joining the small sized plant with medium large and heavily scented flowers. It is widely known and appreciated by its beautiful clones and it has much to offer to breeders because their plants have besides other attributes as small habit and big flowers, many colour variations, form and precocity, becoming flower only four years in ex vitro culture. However, in some of the original places it is becoming a red listed species. Notwithstanding, very little is known about the genetics of these flowers and the variability in the species that is widespread in the Brazilian territory. The aim of this work was to estimate the variability among cultivated materials using the F statistics and to verify if there was inbreeding in plant crosses with similar characteristics, employing as a tool the RAPD simple methodology. The results obtained showed that RAPD was good enough to estimate the variability in C. walkeriana. The selected primers were able to define colour group, especially the coerulea. Inbreeding will occur in crosses of clones with the same colour.