Assessment of Dihaploid Sugar Beet Lines for Resistance to Powdery Mildew and Cercosporose

G. KIKINDONOV
Agricultural Institute, BG-9700 Shumen, Bulgaria

Abstract

KIKINDONOV, G., 2002. Assessment of dihaploid sugar beet lines for resistance to powdery mildew and cercosporose. Bulg. J. Agric. Sci., 8: 515–518

Results from testing dihaploid sugar beet lines for their resistance to the fungal diseases powdery mildew and cercosporose are reported.
Half of the tested multigerm dihaploids are with higher resistance to the agent of powdery mildew (Erysiphe communis Grev. f. betae Jacz.), and nearly all of them have higher resistance to the agent of cercosporose (Cercospora beticola Sacc.) than the initial multigerm population. The tetrahaploids, spontaneously arisen during diploidization of haploid regenerates of the same origin, are significantly more resistant to both diseases, compared with the initial population. Tetrahaploids 49 and 55 exceed the Group Standard with well-proven differences.
The ratings of one and the same genetic material in different doses show, that the higher genes dose does not determine a higher resistance to the agents of the diseases.
The monogerm dihaploid line 19–66 has a significantly higher resistance to powdery mildew and cercosporose than the initial form, and the Group Standard.
The higher relative values of the resistance to the fungal diseases, demonstrated by the dihaploid lines, obtained through induced gynogenesis, are new contribution as results and are indication for the effectiveness of dihaploidy method for creation of resistant to certain pathogens initial material for sugar beet breeding.

Key words: dihaploid, resistance, powdery mildew, cercosporose
Abbreviations: Dh-dihaploid, Th-tetrahaploid, MM-multigerm