PERFORMANCE OF ASPARAGUS GENOTYPES IN FUSARIUM-INFESTED AND UNINFESTED SOIL

For the breeding of asparagus (Asparagus officinalis), satisfactory screening methods for Fusarium resistance are not available, as the pathogenicity of the fungus is dependent on stress conditions caused to the plant and on environmental adaptation of genotypes. With this research the tolerance degree to Fusarium spp. under field conditions of eight commercial cultivars and fifty-six experimental hybrids was investigated through the comparison of results obtained from two adjacent trials: one on soil virgin to asparagus (Fusarium-uninfested) and one on soil where previous asparagus crops had shown severe crown and root rot attributed to the pathogen (Fusarium-infested). The parents of experimental hybrids were doubled haploid (DH) clones, selected for their capacity to survive on Fusarium-infested soil. After the first two years of harvesting, the ratio between total spear yield on Fusarium-infested and uninfested soil was found the most suitable parameter to evaluate the degree of Fusarium tolerance of the tested genotypes.