Genetic variability in Brachiaria ruziziensis for resistance to spittlebugs
Fausto Souza Sobrinho, Alexander Machado Auad, and Francisco José da Silva Lédo
The aim of this study was to evaluate the resistance of B. ruziziensis clones to the spittlebug species Deois schach and Mahanarva spectabilis. Together with the cultivar Marandu (B. brizantha) and the progenies 77s, 85s and 106s as controls, 71 B. ruziziensis clones were evaluated in a randomized block design. Six spittlebug eggs about to hatch were artificially infested and 40 days later evaluated for the percentage of surviving nymphs and plant damage based on a rating scale. Analysis of variance identified significant differences for nymph survival and plant damage of both spittlebug species. Since nymph survival and damage scores of the clones 100, 95, 19, 42, 93, 4, 92, 47, 26, 63, and 58 were similar to Marandu, these can be considered resistant to insect pests. These results, besides demonstrating the existence of genetic variability for a possible selection, offer hope for an identification of B. ruziziensis spittlebug-resistant genotypes.