Linkage maps for nine isozyme and four marker loci in sugarbeet (Beta vulgaris L.)

Summary An analysis of linkage in sugarbeet (Beta vulgaris L.) was conducted for nine isozyme loci, Ak ₁, Gdh ₂, Idh ₁, Lap, Mdh ₁, Mdh ₃, Pgi ₂, Pgm ₁,and Skdh ₂,and four marker loci, annuality (B), red hypocotyl-color (R), pollen fertility restorer (X), and monogermity (m). Four linkage groups were identified; R-B-Idh ₁, Gdh ₂-Mdh ₁, Ak ₁ -Lap, and Mdh ₃-Pgm ₁.In addition, X was linked to Mdh ₁and Skdh ₂with a recombination value of 13.4% and 34.7%, respectively, and m was linked to Pgm ₁with a recombination value of 35.8%. Pgi ₂was inherited independently of the four linkage groups. This locus showed a skewed ratio in F₂ progeny of a cross between self-compatible and self-incompatible lines and the allele derived from self-incompatible parents decreased markedly. On the other hand, the expected segregation ratio was observed in the backcrossed progeny and also in F₂ progeny of a cross between self-compatible lines. The results obtained suggest that Pgi ₂may be linked to a self-compatibility locus (S ^f)and the two loci may be assigned to an additional linkage group.