Recent Progress of Asparagus Breeding in Italy

Asparagus breeding in Italy is based on production of doubled haploid androgenetic (DH) clones and synthesis of two ways and three ways all-male hybrids obtained by mating DH male clones with DH or hererozygous female ones. 167 DH female and male clones out of 1,803 so far obtained, were selected in the field for plant vigour and/or resistance to rust (Puccinia asparagi) and tolerance to purple spot (Stemphylium vesicarium). By mating DH or heterozygous clones with DH male clones 450 F-1 "two ways" and "three ways" all-male hybrids were evaluated for green or white spear production. At present four out of nine F-1 all-male hybrids so far released commercially are widely spread in north Italy and one in south Italy. However, the results obtained during the last ten years demonstrated that probability to find new superior hybrids is very low. Therefore the breeding programme has been oriented toward the production of new DH clones by applying recurrent in vitro anther culture of the best anther donor genotypes and by the introgression of rust resistance and spear traits from tetraploid cultivar 'Montina' (A. maritimus), A. acutifolius and A. officinalis 'Violetto d'Albenga' into the existing DH clones. Following in vitro anther culture of tetraploid lines derived from interspecific crosses and of 'Violetto d'Albenga' cultivar, di-haploid (DiH) clones with the desired traits were obtained. Two DH and three heterozygous female clones with different level of resistance to rust were mated with the two more vigorous and rust resistant DiH male clones. Results obtained demonstrated the complete rust resistance can be introgressed from 'Montina' (A. maritimus) into DH clone, but molecular markers are necessary to assist and speed up the selection process.