ABSTRACT
Wide hybrids for sugar beet (Beta vulgaris) improvement have been sought for introgression of high levels of resistance and even immunity to diseases and pests, notably to sugar beet cyst nematode. Unfortunately, many such hybrids are difficult to make, and once made, regular chromosome pairing and recombination between donor and recipient chromosomes is limited or non-existent. Taxonomic revisions over the past decade better reflect the biological relationships between species, and in the instance of sugar beet cyst nematode, transfer of resistance was accomplished through translocation of a chromosome segment from what is now recognized as species within a different genus. Other more closely related species also have potential for sugar beet improvement but their use has been more limited. Recent trends to access underexploited germplasm have targeted the wild beet forms of Beta vulgaris, and thus few breeding programs are using interspecific hybrids. However, genomic approaches applied to the wild relatives may uncover the genetic basis of high levels of disease and pest resistance and thus allow directed improvement of sugar beet by other means than direct inter-specific and inter-generic hybridization.
