Association of genes from different sources of resistance to major cacao diseases

Abstract

This study aimed to select genotypes resistant to witches’ broom (WB) and black pod (BP), major cacao diseases in Brazil, as well as incorporate resistance genes to moniliasis supplemented by clones EET75 and UF273, forming populations of second-cycle recurrent selection. Moniliophthora perniciosa (2 × 105 basidiospores/mL) was inoculated on 30-day-old seedlings from 72 different progenies, being assessed 60 days later, and a mixture of four isolates of Phytophthora palmivora (3 × 105 zoospores/mL) was inoculated on leaf discs from 58 progenies, observing lesions after seven days. Significant effects of progeny were observed in the tests of resistance to both diseases (p < 0.05). Scavina-6 expressed resistance to both pathogens, 26 crosses did not differ from free-pollinated progenies of Scavina- 6 for WB, and ten crosses were higher and 27 similar for BP. Eight crosses were largely resistant to both diseases.