Discriminação Varietal de cultivares em Urochloa brizantha por marcador molecular ISSR

Abstract

Approximately 80-90% of grassland areas in Brazil consist of the forage Urochloa, genus and the apomictic species Urochloa brizantha [syn. Brachiaria brizantha (Hochst. ex A. Rich.) Stapf.] the most used. Some genotypes of Urochloa have being widely used with a wrong nomenclature, even for species as for cultivars. In this way, the Urochloa cultivar identification is primordial for breeding programs and seed production. Considering the importance of genetic purity in comercialized seed lots, the present study aimed to investigate the potential of ISSR markers for discrimination of U. brizantha (Xaraés; Piatã, Basilisk; MG4; MG5; Marandú) in order to determine the degree of contamination of seed lots. ISSR markers showed a low degree of polymorphism . However, results showed it is possible to identify cultivars in pure samples of seeds Urochloa, requiring only ten primers. The cultivar Basilisk was confirmed as U. brizantha cultivar. It was not possible to differentiate samples intentionally contaminated at levels stipulated in the work. Further studies with other primers and other contamination levels will be important to detect varietal mixtures in cultivars U. brizanhta.