The aim of the planned project is to accomplish an early and reliable selection of growth types of the columnar apple, that are best suited for commercial growing systems, on very young plants from crossings. To achieve this, a combination of a few molecular markers will be identified. In combination with other already known markers such as the one for the typical apple aroma (Rowan et al., 2009; Souleyre et al., 2014) an early selection system for the combination of valuable traits including the growth habit of the future trees will be established. To further develop the early selection system, a fast breeding approach will be adopted to allow for a very efficient development of new varieties for the growers. This will allow for a fast introduction of an effective and economically sound production system for a regional production of cider apples for the fruit juice industry. The very effective production system will allow for a production where both, grower and juice industry, work on an economically feasible basis providing income opportunities for both sides.

Two independent progenies from crosses of a heterozygous columnar parent and a parent with normal growth type (expected outcome for each progeny 50% heterozygous columnar, 3 trees per individual, 300 individuals per progeny) have been produced in preparation for this project. The trees will be phenotyped in the winter 2017/2018. For genotyping, random tagging Genotyping by Sequencing (rtGBS) approach followed by sequencing, alignment to the reference genome, a SNP detection and a genome wide association study using the data from the phenotyping will be used to find QTL ́s and the respective markers for the wanted growth type. The results will be validated using an independent progeny of similar size.