Screening and genetic studies on resistance to Soil-born Cereal Mosaic Virus (SBWMV) in rye

Abstract

Due to several reasons soil-borne viruses such as the furoviruses, i. e., cereal mosaic virus (SBCMV) and wheat mosaic virus (SBWMV) as well as the bymovirus wheat spindle streak mosaic virus (WSSMV) gained importance in cereal breeding including rye. High yield losses are recorded, today. Since there is no or little resistance to these viruses in modern rye cultivars, an extended screening for resistance was initiated. In addition to earlier screenings, 37 rye genotypes were tested for resistance. Among them, three genotypes were found with persistent resistance to SBCMV. They belong to Secale montanum and S. vavilovii species, i. e., wild types of rye. One accession, PC2243 (S. montanum), was used as a resistance donor for the present genetic study. In F2 generation, it was observed that resistance to SBCMV is independently inherited from WSSMV. The evaluation of the ELISA values pointed to a 3:1 distribution assuming duplicate dominant epistasis. Molecular marker analysis supports this segregation pattern. By composite interval mapping a QTL on chromosome 2R could be detected. It can be assumed that there is a DNA region of about 13 cM on the long arm of chromosome 2R (2RL) harboring SBCMV resistance with the closest markers “C9654_1947” and “isotig11640”.Moreover, genotypes with a yellow seed coat showed practically no infection with SBCMV. Thus, the resistance gene could be linked to the allele an1 determining non expression of anthocyanins. This locus was also mapped earlier on chromosome 2R.