African Journal of Biotechnology Vol. 5 (22), pp. 2041-2048, 16 November 2006   

ISSN 1684–5315 © 2006 Academic Journals        

Full Length Research Paper

RAPD markers associated with resistance to blackleg disease in Brassica species

Anthony O. Ananga¹, Ernst Cebert¹*, Khairy Soliman¹, Ramesh Kantety¹, R. P. Pacumbaba¹ and Koffi Konan²

¹Department of Plant and Soil Sciences, Alabama A&M University, Normal Al, 35762, USA.

²Department of Food and Animal Sciences, Alabama A&M University, Normal Al, 35762, USA.

*Corresponding author. Phone: 1-256-372-4243. Fax: 1-256-372-5429. Email: ernst.cebert@email.aamu.edu.

Accepted 19 October, 2006

Abstract

Blackleg, caused by Leptosphaeria maculans, is a serious disease of Brassica species. Genetic analysis of resistance to L. maculans was carried out with 15 accessions from the USDA Brassica germplasm collections, representing diploids (A, C), and tetraploid (AC) genomes, respectively; and 9 cultivars from the National Winter Canola Variety Trials (NWCVT) all carrying AC genomes. All genotypes were screened for blackleg disease at the cotyledonary stage. The results indicated that 46% of the 24 genotypes were resistant, while 54% were susceptible. On the other hand, adult plant screening revealed that all the public genotypes were resistant. In an effort to identify molecular markers associated with resistance to blackleg disease, all genotypes were screened with 13 RAPD and 8 SSR markers producing 169 amplified products. Six RAPD markers (OPB01, OPE03, OPE16, OPF10, OPE12, and OPI01) were polymorphic, while the SSR markers were monomorphic. Chi-square analysis indicated that 5 amplified fragments (OPE03-4000, OPE16-1100, OPE16-1300, OPE16-1900, and OPI01-280) from RAPD primers were significantly associated with blackleg resistance. Thus this study demonstrated that RAPD primers could be effectively used to identify DNA markers that are associated with blackleg disease resistance, and that resistance to L. maculans might also exist in the A and C genomes.

Key words: Leptosphaeria maculans, Pathogenicity, Innoculum, Brassica napus.