Genetic analyses of flowering time and disease resistance in a sour cherry population

The tetraploid Prunus cerasus L. (sour cherry) is an economically important Prunus species. The sour cherry is a segmental allotetraploid (2n=4x=32) and a hybrid of the diploid sweet cherry (P. avium L. – 2n=2x=16) and the tetraploid ground cherry (P. fruticosa Pall. – 2n=4x=32). In this study, we established a population by crossing the historic European sour cherry cultivar ‘Schattenmorelle’ and a clone ‘PC2’, leading to 102 F₁ individuals. These F₁ individuals and their parents were genotyped with the cherry 6+9K SNP array and the data was analyzed using the autopolyploid module of GenomeStudio. We also tested and mapped Prunus simple sequence repeat markers (SSRs) in this population. Furthermore, we established a genetic map and generated phenotypic data of the individuals to investigate the genetic basis of flowering time as well as resistance to cherry leaf spot, caused by the fungus Blumeriella jaapii Rehm. We identified and mapped QTLs of significant LOD scores for both traits to chromosomes in the ‘Schattenmorelle’ parental map. We present these preliminary results and discuss their implications.