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Segregation of resistance characters in some apple progenies after artificial infection with Venturia inaequalis

Ion, L., Hoza, D., Asanica, A., Neagu, T., Ciomaga, F., Moale, C.
Acta horticulturae 2013 no.981 pp. 157-161
DNA, Malus floribunda, Venturia inaequalis, apples, chemical control, cultivars, disease control, fungicides, genetic markers, greenhouses, growers, income, loci, marker-assisted selection, orchards, pathogens, progeny, spraying equipment, spring, trees
Apple scab, Venturia inaequalis (Cke) Wint., is a major problem in Romanian apple orchards and is responsible for serious economic losses. The purchase of spraying equipment and phytopharmaceutical products is very expensive in comparison to the income of local apple growers. This is one of the reasons why reduced fungicide sprayings are becoming more and more important. Current disease control is achieved mainly through scheduled applications of fungicides. The Venturia inaequalis is an aggressive pathogen difficult to control once it is established in an orchard. Because a chemical control is so difficult, it was desirable to promote the breeding of cultivars resistant to this pathogen. Prospecting through Romanian apples collections has leaded us to the discovery of several sources of resistance to Venturia inaequalis. The different columnar or spur apple varieties were chosen among the different sources of resistance as it could also be used to develop a valuables resistant variety. This new program was started in spring 2010. The artificial inoculation in the greenhouse was performed with race 6 on trees of Malus floribunda 821. A large variation in resistance and (or) susceptibility was observed among the individuals of the progeny. The breeding of apple cultivars resistant to Venturia inaequalis could be much improved by marker-assisted selection. A molecular marker closely linked to the resistance locus called Vf could replace selection based on infection studies. To find such molecular markers, DNA of progenies from crossings of a resistant and a susceptible apple tree will be subject to bulked segregant analysis.