Use of S-alleles and microsatellite genotyping for parental identification and to verify interspecific hybridization in a Chilean Prunus rootstock breeding program

Abstract

The use of molecular markers to complement phenotypic selection has potential for making both scion and rootstock breeding programs more efficient. Additionally, molecular markers can be used for cultivar identification and to test the hybrid nature of the segregants. In Chile, the Centro de Estudios Avanzados en Fruticultura (CEAF), started a breeding program for Prunus rootstocks where a series of interspecific crosses are underway, based on a Prunus germplasm collection available at this center. Molecular markers were used for cultivar identification and for determining the hybrid nature of individuals coming from interspecific crosses. For cultivar identification, S-allele genotyping was used to characterize 23 Prunus rootstocks. Preliminarily, these results allowed the differentiation between genotypes coming from seed propagation from those clonally propagated. To test for true hybrids arising from interspecific crosses, S-allele genotyping were used together with microsatellite markers. A population of about 100 seedlings, arising from the cross of P. mahaleb × P. avium, both diploid species, turned out to be selfs of P. mahaleb. A second population of 26 seedlings obtained from the cross of P. avium (2n=16) × P. cerasus (4n=32), resulted, as expected, in triploid hybrids (3n=24). These results are useful both to make the program more cost-effective and to allow for better planning of the interspecific crosses.