Resistance to Polymyxa betae in Beta Species of the Section Procumbentes, in Hybrids with B. vulgaris and in Monosomic Chromosome Additions of B. procumbens in B. vulgaris

Abstract

AbstractResistance to Polymyxa betae was studied in Beta species of the section Procumbentes, in hybrids of B. vulgaris with B. procumbens or B. patellaris, and in monosomic additions of chromosomes of B. procumbens in B. vulgaris. In all experiments P. betae infested with beet necrotic yellow vein virus (BNYVV) was used. This virus causes rhizomania in sugar beet, and the effect of vector resistance was studied by measuring virus concentrations. Cystosori of P. betae were not found in the wild species and the hybrids. Virus concentrations in these plants were low, and in half the number of plants the virus could not be detected. Results of experiments with the monosomic additions indicate, that resistance to P. betae in B. procumbens is located on chromosomes 4 and 8. Some cystosori were present in these addition types, while cystosori were abundantly present in other addition types and all sib‐plants. Virus concentrations in the addition types 4 and 8 were lower than in their sib‐plants, but in almost all plants the virus could be detected. A significant correlation (r = 0.91; P < 0.05) between average numbers of cystosori and average virus concentrations was found when addition families of type 8 were tested together with B. procumbens and B. vulgaris cv. ‘Regina’.