New breeding technology approaches to improve apple and pear cultivars

Genome editing and cisgenesis are powerful techniques for achieving precise genome modifications, and are of particular interest for crops presenting a long juvenile phase and high heterozygosity, like fruit trees. Apple (Malus × domestica) and pear (Pyrus communis) are two important pome fruit crops worldwide but, in recent years, several challenges, such as pathogen attacks, unfavourable conditions during flowering and extreme weather events produced significant yield losses. Accordingly, various new breeding techniques (NBT) approaches have been started in apple and pear with the aim to obtain improved cultivars for some of these traits; e.g., resistance to fire blight and self-compatibility. Nowadays, a fire blight resistance gene (FB_MR5) and another candidate for the same trait (MF_Mfu10) have been identified in wild apples. The recent availability of Malus/Pyrus hybrids opens the possibility to consider the transfer of apple resistance genes to pear as a cisgenic approach. In addition, the availability of apple fire blight susceptibility genes (i.e., DIPMs) makes it possible their knockout by the CRISPR/Cas9. Finally, for improving pear productions, self-compatible pear genotypes are under development by DNA editing. The first results of these experiments will be presented.