Institut für Züchtungsforschung an gartenbaulichen Kulturen
In 2022, asparagus was cultivated on about 200.000 hectares worldwide with the highest production in China, Europe and Peru (FAOSTAT, 2024). Virus diseases are quite common in asparagus production and can reduce the vigor, yield and economic lifetime of asparagus plants. Severe stunting and yellowing can be observed for infected plants with both asparagus virus 1 (AV1) and cucumber mosaic virus (CMV). Mixed infections can lead to crop losses between 20% and 49.5%, respectively (Kegler et al. 1991, Knaflewski et al. 2008). Histopathological analyses have shown that in AV1 infected cells, organelles such as chloroplasts and mitochondria are partially destroyed (Lantos et al. 2023). As far as known, asparagus is the only natural host for AV1 and the virus is transmitted non-persistently by vectors, primarily aphids (Gaafar et al. 2024). AV1 is now widespread in all asparagus growing areas worldwide (Lantos et al. 2023, Gaafar et al. 2024). While no cultivars of A. officinalis are known to be resistant to AV1 (Howell 1985, Kegler et al. 1999, Knaflewski et al. 2008, Nothnagel et al. 2017), some resistances have been identified in various asparagus wild relatives (Nothnagel et al. 2014, 2017). In the meantime was realised the transfer of AV1 resistances from A. prostratus (AV1pro) and A. amarus (AV1ama) into pre-breeding material of A. officinalis (Plath et al. 2018, Nothnagel et al. 2022). For AV1pro resistance, a monogenic dominant inheritance was demonstrated in the breeding material and closely linked KASP markers on chromosome 2 were developed (Nothnagel et al. 2022). In current studies, further backcrosses have been performed to select individual plants that show significantly reduced introgression compared to lines described in former publications.Furthermore, initial WGS analyses on BC4 lines of A. amarus x A. officinalis showed that AV1ama resistance is most likely due to an introgression in the terminal region of chromosome 10.The AV1ama resistant BC4 material has predominantely reached the diploid chromosome level, but the fertility (seed formation) is still limited.The aim of the project is the further development of advanced introgression lines with AV1 resistance, from the wild species A. prostratus and A. amarus as pre-breeding material to transfer into the commercial asparagus breeding.
Limgroup B.V.
