Mixed models in the selection of interspecific crosses of Psidium spp. resistant to myrtle rust

Myrtle rust severely impacts guava cultivation. Currently, no rust-resistant guava cultivars have been found. This study aimed to identify rust-resistant plants from interspecific crosses of Psidium spp. using mixed models. Twenty-six crosses were evaluated in a greenhouse from September to October 2020. Inoculation was performed on young leaves and floral buds, and characteristics such as the latent period, infectious period, and area under the disease progress curve were measured to determine variance components and genetic parameters. Genotypic values were analyzed, and clones were ranked using mixed models. The genetic, environmental, and broad-sense heritability values varied from moderate to high. Mixed models revealed genetic variability for rust resistance. Clones from the Cv1 x Cv11 and Cv8 x Cv11 crosses were immune to rust. The P36 x P11 cross exhibited variability. The results of this study indicate the selection of clones that are immune and resistant to rust for use in future recombination.