CONTRIBUTION OF BIOTECHNOLOGY IN GENETIC STUDIES AND BREEDING OF LOQUAT AT IVIA, SPAIN

Loquat [Eriobotrya japonica (Thunb.) Lindl.] is a member of the Rosaceae, subfamily Pomoideae which contains a number of important fruit crops including apple and pear. Breeding and cultivar improvement of loquat is focused on selecting new genotypes with high fruit quality, resistance to pests and diseases and an extended flowering and ripening season which would allow a longer productive calendar to satisfy the requirements of the market. Conventional breeding of fruit trees is constrained by their long juvenile periods, the size of the progenies and the space and labor cost. The new techniques of biotechnology base on recombinant DNA technology has become a powerful tool and offers an alternative to overcome limitations of conventional breeding. Development of molecular markers linked to the traits of interest has the advantage of selecting the desirable genotypes in the early stages of development of the plants. Molecular markers as random amplified polymorphic DNA (RAPDs) have been used for identification of accessions and genetic diversity studies. The transportability of markers between species from a common genus was demonstrated. Recently, simple sequence repeat or SSRs from apple has been applied to genetic studies of loquat. According to the conservation of genome organization between close related species, several molecular resources developed on apple as linkage maps and resistance genes will be available for loquat. Development of SSRs from loquat is another alternative to produce a high output marker system suitable for construction of linkage maps, which could include position of traits. Development of markers tightly linked to important traits, quantitative character dissection, using linkage maps and candidate genes approaches, are the new genomic tools provided by the biotechnology to improve genetic studies and breeding of loquat.