Genetic diversity in apple populations from Queretaro, Mexico revealed by RAPD markers

Apples (Malus domestica Borkh.) are the most important temperate fruit crop grown in Mexico, with 62 000 ha cultivated in 2003, and 700 of than are estiblished in Queretaro. Lack of germplasm control by growers or government means that some varieties and hybrids, are unknown. Woolly apple aphid (Eriosoma lanigerum) has a considerable effect on apple production in Queretaro and it is unclear whether or nit the material is grafted onto in resistant rootstocks. In order to evaluate the apple diversity in Queretaro, 65 samples of cultivars, landraces, hybrids and rootstocks were collected and analyzed using RAPD (Randomly Amplified Polymorphic DNA) markers. Ten primers were selected for the DNA analysis. One hundred and thirteen polymorphic and 29 common bands were amplified. Cluster analysis showed that the greatest distance observed in the dendro-gram was 0.71. The samples were separated in two conglomerates, the first group included almost all of the genotypes related to 'Golden Delicious' variety while the second included most of the samples corresponding to red apples and clonal rootstocks. Results indicate that the genetic diversity in apple is important in the region and that the RAPD method allowed to group genotypes with common characteristics, which will facilitate the genetic identification of varieties.