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Downy mildew (Plasmopara viticola) is the main grapevine disease in

-The evolution of leaf scald (Xylella fastidiosa) resistance was evaluated in individuals of seven plum segregating populations, consisted of seedling progenies originating from crosses involving nine plum cultivars, with varied levels of resistance. Plants were submitted to artificial inoculation in 2001 and evaluated annually from 2002 to 2007 for the evolution of leaf scald symptoms. All populations showed an evolution of symptom severity during the evaluated period. The population Amarelinha x Carazinho was the most resistant while populations Chatard x Santa Rosa and Chatard x Simka were the most susceptible ones. The populations Chatard x Harry Pickstone and Chatard x Angeleno exhibited an intermediate behavior. The analysis of genetic segregation of microsatellite markers and disease resistance curves in different populations indicated that inheritance to leaf scald resistance is polygenic and predominantly recessive, with an eventual presence of major QTLs in susceptible parents.

• Premise of the study: Microsatellite primers were identified and characterized in Acca sellowiana in order to expand the limited number of pre-existing polymorphic markers for use in population genetic studies for conservation, phylogeography, breeding, and domestication.• Methods and Results: A total of 10 polymorphic microsatellite primers were designed from clones obtained from a simple sequence repeat (SSR)–enriched genomic library. The primers amplified di- and trinucleotide repeats with four to 27 alleles per locus. In all tested populations, the observed heterozygosity ranged from 0.269 to 1.0.• Conclusions: These new polymorphic SSR markers will allow future genetic studies to be denser, either for genetic structure characterization of natural populations or for studies involving genetic breeding and domestication process in A. sellowiana.

Abstract:Among the cultivation problems of apple production in Brazil, Apple Leaf Spot (ALS)