Natural triploids of wild cherry

Abstract

Research of triploid individuals was carried out in the French wild cherry ( Prunus avium L.) collection at the Institut National de la Recherche Agronomique (INRA), Orléans, France, using 12 microsatellite markers and the S gametophytic incompatibility marker. For 11 of 312 clones (3.5%), we found three different alleles or two different alleles included one doubled allele for 10–12 markers spread along five of the eight chromosome pairs in wild cherry. The cytometry analysis confirmed that triploidy was genome-wide. No new allele was observed among the triploids compared with the diploids of the wild cherry collection: these triploids probably result from diploids through the production of unreduced gametes, and not from interspecific hybridation. A comparison of the height growth, diameter growth, and resistance to leaf spot among 38–85 clones in four 6- to 10-year-old clonal field trials showed that six triploids were among the best compared with the diploids. The dimensions of the leaves were somewhat larger, and the petals were always larger for nine triploids compared with 20 diploids observed on plants of the wild cherry collection of INRA. Three triploids are already used as clonal variety or component of a seed orchard. We discuss the need to include more triploids in the wild cherry breeding programme.