Use of genetic resources and partial resistances for apple breeding

Summary

Modern apple breeding strategies are mainly considering the most advanced selections and culti-vars as parents. This tends to lead to a narrowed genetic basis. The introgression of traditional va-rieties and accessions of the gene pool is often feared due to undesirable characteristics that might be incorporated. However, there is scope for considering a wider genetic basis in apple breeding to support sustainable fruit production systems. The focus at Agroscope Changins-Wädenswil (ACW) is put on high fruit quality combined with low susceptibility to scab (Venturia inaequalis), fire blight (Erwinia amylovora), and powdery mildew (Podosphaera leucotricha). The Swiss scab and fire blight resistance research programs are focused on developing and applying molecular markers for resistance factors. In this context we are also mining our national germplasm collections of heritage varieties. Heritage varieties are traditional and/or special use apple varieties. Many of them were discovered in the course of a national inventory over the past 5 years. As a result of this inventory, 1’100 apple and 670 pear accession are being added into the germplasm collections. They will be evaluated in the coming years for different fruit and tree characters.