Localization of Genetic Factors that Determine the Economically-Useful Traits of the PEAR (<i>Pyrus</i>) and Methods of Marker-Assisted Selection

DNA markers are an alternative method for accelerated identification of interested genes and loci at the early stages of ontogenesis, and, consequently, DNA markers are able to intensify the breeding process. This article represents overview of research on the localization of economically useful traits in the pear genome and the development and use of marker-assisted selection (MAS) techniques. At the moment, several traits have been localized in the pear genome, i.e.: resistance to scab European (V. pirina Aderh) and Asian (V. nashicola), black spot (Alternaria alternata (Fr.) Keissler), brown spot (Stemphylium vesicarium), fire blight (Erwinia amylovora), pear psylla (Cacopsylla pyri), pear sawfly (Caliroa cerasi), pear blister mite (Eriophyes pyri), self-incompatibility, dwarf trait. Major genes and loci of quantitative traits (QTLs) of fruits characteristics have also been identified, namely: skin color and rustiness of the fruit, size and weight of the fruit, taste, level of ethylene production, harvest time etc. It should be noted that currently Russian research is limited to the validation and use of MAS methods developed abroad. According to the experience of Japanese scientists, the use of MAS for several key traits has made it possible to triple the efficiency of the breeding process. Despite the currently limited list of MBC methods for pears, the high speed of genomic technologies development promises rapid development of new MAS methods in the future. In combination with new breeding technologies (New Breeding Techniques) based on accelerated flowering, the use of MAS for pears is a promising direction of breeding.