Grupamento de progênies obtidas de cruzamentos entre clones cerúleos de Cattleya walkeriana por meio de RAPD

Abstract

Cattleya walkeriana is widely grown by collectors and receive special attention by the breeders because it exhibit a rare colour variation and a great visual effect. RAPD markers (Random Amplified Polymorphic DNA) are one of the molecular markers most used in genetic studies. They have advantages, such as low amount of genomic DNA, hybridization absence, gene amplification at low costs and easy implementation. The DNA extracted from Cattleya walkeriana plants, wild and from cerulean offsprings, was amplified by elected RAPD primers. With the generated bands it was possible to estimate the fixation allelic index (FST) and to construct a dendogram. It could be inferred that Cattleya walkeriana is an allogamous species and that was a decrease in the genetic variability among the crosses as the recessive plants were used. Cerulean plants are difficult to obtain since they have all the pairs of genes in the recessive form. The inheritance for the trait in question is oligogenic and determined by genes that act in a complementary manner and are segregated independently.