Progress in the development of garden asparagus resistant to Asparagus virus 1 (AV-1)

A genetically determined resistance to the Asparagus virus 1 was identified within the Mediterranean wild relative Asparagus amarus. Field experiments under climatic conditions in Germany showed for A. amarus a relative low yield potential (~20%) compared with various cultivars of A. officinalis. Analyses of volatile organic compounds revealed a number of significant differences. Furthermore, the wild relative is hexaploid (2n=6x=60), expresses a strong bitter taste and is frost tolerant up to -15°C. A backcross programme was started for introgression the AV-1 resistance from the wild relative into the genome of garden asparagus. Interspecific hybrids were obtained by reciprocal crosses between A. amarus and tetraploid A. officinalis via embryo rescue approach. Four F1 progenies were cloned in vitro and transplanted in the field. Two progenies showed resistance to AV-1, while two progenies were susceptible.