Marcadores moleculares para detecção de variabilidade genética em variedades de palma forrageira

Abstract

The cactus forage (Opuntia fícus-indica) is one of the basic sub-existence supports in dairy farming, mainly in the arid and semiarid regions. The culture of this plant is acknowledged within research programs for the development of sustainable agriculture in the northeast region of Brazil. The analysis of genetic variability is of great importance in the conservation and characterization of germoplasm in order to group the material and allow for a more adequate management of the collections. This work aims at genetically characterize, by means of ISSR and RAPD molecular markers, the variability in five varieties of O. ficus-indica, which stand out for their agronomic characteristics, in order to obtain information which will aid future improvement programs of this culture. Out of the 20 primers used, five ISSR and six RAPD primers were selected because they present better polyphormic patterns. The dendrograms, which were formed based on the two markers used, grouped the cacti varieties into four subgroups. Results revealed high genetic similarity between the varieties assessed; however, some differences were made evident. The Chili Fruit variety was isolated in one subgroup; varieties Copena F1 and Clone IPA 20 were grouped together, as well as varieties Copena VI and Redonda. These results are still preliminary and further analysis with larger amount of primers of the used markers may be useful in the study of the genetic diversity among the varieties of cactus forage assessed in this study. The knowledge of the distribution of the genetic variability among the cacti together with the study of promising genotypes based on morphologic characters, will allow for improvers to have faster genetic gain for this forage, besides the possibility of using these markers as molecular descriptors. KEYWORDS: