GENOMIC TOOLS ENHANCE POWER AND PRECISION OF HAZELNUT BREEDING
European hazelnut (Corylus avellana L.) is the only economically important nut crop in the family Betulaceae. Because of its small genome size (~385 Mb/1C), relatively short life cycle, availability of a dense linkage map, and amenability to transformation by Agrobacterium, the European hazelnut could serve as a model plant for the Betulaceae. Genomic resources are being developed and used in the hazelnut breeding program at Oregon State University (OSU) to develop new cultivars that combine suitability to the blanched kernel market with resistance to eastern filbert blight (EFB) caused by the ascomycete Anisogramma anomala (Peck) E. Müller. Genetic resistance to EFB was first identified in the obsolete pollinizer Gasaway, and most advanced selections carry this resistance. In order to better understand the mechanism of resistance, map-based cloning of the Gasaway resistance gene was initiated by constructing a bacterial artificial chromosome (BAC) library for Jefferson, which is heterozygous for resistance. A high-resolution genetic map of the resistance region was created with 51 markers and the resistance phenotype in a mapping population of 1488 seedlings. In parallel, a physical map was constructed. The BACs in this region were sequenced using Illumina technology and the resistance region was identified as a single contig of three overlapping BACs. Ab initio gene annotation of the sequence information revealed five candidate genes, two of which are reported to have disease resistance properties. Additionally, 150 new SSRs were developed from mining the transcriptome sequences. Future studies will focus on the S-locus which controls sporophytic incompatibility and gene expression in styles after pollination.
Sathuvalli, V.R., Mehlenbacher, S.A., Peterschmidt, B.C. and Smith, D.C. (2014). GENOMIC TOOLS ENHANCE POWER AND PRECISION OF HAZELNUT BREEDING. Acta Hortic. 1052, 23-25
Corylus, filbert, map-based cloning, molecular markers