EPAGRI hybrid apple cultivars resistant to Glomerella leaf spot have the Rgls resistance gene

Abstract

Abstract Glomerella Leaf Spot (GLS) is the main disease of the ‘Gala’ apple cultivar in Brazil. Recent studies have suggested that the resistance of apple trees to GLS is controlled by a recessive gene called Rgls. This study investigated whether EPAGRI new apple cultivars have this resistance gene. The cultivars evaluated were ‘Fuji Suprema’ and ‘Gala Real’, which are standards of resistance and susceptibility to GLS, respectively, and the new apple cultivars selected by the phenotypic resistance to GLS: ‘Monalisa’, ‘Luiza’, ‘Venice’, ‘Isadora’ (hybrids) and ‘Gala Gui’ (spontaneous 'Gala' mutant). The DNA of cultivars was extracted and amplified using the SSR S0506206 molecular marker. RT-PCR was performed, and its products were evaluated by electrophoresis in 2% agarose gel. The new hybrid apple cultivars exhibited amplified DNA fragments similar to those of ‘Fuji Suprema’, indicating the presence of the Rgls gene. However, ‘Gala Gui’ cultivar showed amplified DNA fragments similarly to the ‘Gala Real’ susceptible cultivar. The results suggest that the genetic resistance of apple trees to GLS may be regulated by genes other than Rgls, particularly for spontaneous 'Gala' mutants that are phenotypically resistant to GLS.

Keywords

• Colletotrichum spp.
• genetic resistanc
• molecular markers