Analyses of economically important traits in ornamentals with complex genomes

Abstract

In contrast to model plants and major agricultural crops genetic research and breeding in ornamentals is difficult due to some problems specific to ornamentals. Due to a large variety of cultivated ornamental crops resources for research and breeding for individual crops are smaller as compared to major agricultural crops. In addition, polyploid large genomes, long generation times and recalcitrance for biotechnological approaches are also negative factors. Here, examples from our research on resistance of roses to pathogens will be presented. In tetraploid progenies with a tetrasomic mode of segregation the development of new markers linked to resistance genes is difficult due to a low sensitivity for markers linked in repulsion. An alternative approach uses linkage disequilibrium in an association set of 96 rose varieties to detect markers associated to pathogen resistance and other traits. As markers an Axiom SNP array and KASP markers were used. Examples for associated markers and their validation in independent populations as well as technical challenges of SNP calling in tetraploids will be shown. Finally first results for the RNAi and CRISPR based knock down and knock out of rose MLO genes will be presented.