Lack of antibiosis against Mahanarva spectabilis (Distant) (Hemiptera: Cercopidae) in Cenchrus purpureus (Schumach.) Morrone germplasm
Alexander Machado Auad, Luís Augusto Calsavara, Fausto Souza Sobrinho, Francisco José da Silva Lédo, Juarez Campolina Machado and Antônio Vander Pereira
Abstract: This study examines Cenchrus purpureus with the aim of identifying genotypes and select plants progenitors resistant to Mahanarva spectabilis (Distant, 1909) for future recurrent selection from the elephant grass germplasm bank. Six M. spectabilis eggs were inserted into each plant of 138 elephant grass genotypes. After 35-45 days the percentage of nymphal survival was assessed. Despite the large variation in insect survival there were no significant differences in the joint analyses of bioassays conducted from 2008 to 2024. None genotype yielded an insect survival rate of less than 30%, and fewer than 10% of the genotypes showed a survival rate of less than 50%. These genotypes should be intercrossed, forming a new population each year, with the aim of increasing the presence of favorable alleles for resistance to this insect pest, with the goal of producing genotypes that achieve future M. spectabilis nymph mortality greater than 70%.