Inheritance of resistance to spittlebug (Homoptera: Cercopidae) in interspecific Brachiaria spp. hybrids

Apomictic cultivars of several Brachiaria Griseb. spp., selected directly from collections of natural germplasm, are the most widely sown forages in the tropics. They are particularly well adapted to acid, infertile soils typical of the vast South American savannas. Species of several genera of spittlebugs (Cercopidae) cause widespread and severe damage to pastures of susceptible Brachiaria cultivars. Highly antibiotic genotypes have been identified. The potential for genetic manipulation of resistance in highly antibiotic genotypes was assessed. A positive correlation between topcross parent and F1 family mean for percentage of adult emergence of Aeneolamia varia F. on artificially infested plants in the greenhouse indicated that resistance is under genetic control and should be easily manipulated in a plant breeding program. In a field study, heritability of spittlebug damage score on naturally infested plants was estimated from replicated half-sib families. The estimate of heritability of half-sib family means was 0.44 (plus or minus 0.098) 5 mo after transplanting, further supporting the conclusion that resistance can be readily manipulated in a breeding program eng