Flow cytometry and RAPD markers applied to parentage analysis within Actinidia genus

Two A. arguta female clones were planted together with A. deliciosa cv. Hayward and with A. deliciosa pollinators in a geographically isolated commercial orchard with no other cultivars close by. Seeds were collected from these two female clones of A. arguta and were supposed to be 5x interspecific hybrids between A. arguta (2n=4x) and A. deliciosa (2n=6x). However, ploidy level determination of the progenies showed unexpected results: some individuals were pentaploid, as expected, but the others were diploid. Random amplified polymorphic DNA (RAPD) markers generated via the polymerase chain reaction amplification of genomic DNA sequences appears to be very useful for analyzing genetic relationships in plants. Here, the analysis of the progenies and the putative parents revealed the presence of bands common to both the A. deliciosa males and the pentaploid individuals, though absent from the diploid individuals. This study not only provides evidence of the existence of 5x and 2x progenies from 4x x 6x crosses but also demonstrates the usefulness of flow cytometry and DNA markers for parentage determination.