Location: Horticultural Crops Research2010 Annual Report
1a. Objectives (from AD-416)
Develop improved germplasm and cultivars of hazelnut with resistance to eastern filbert blight and suitability for the kernel market.
1b. Approach (from AD-416)
The general approach relies upon plant breeding complemented by marker-assisted selection. Two strategies are proposed, one utilizing a known dominant gene (from 'Gasaway') for resistance to eastern filbert blight (EFB), with the second strategy seeking and exploiting other sources of EFB resistance. For the first strategy, seedlings from crosses will be screened initially for the presence of the 'Gasaway' gene using DNA markers that flank the resistance gene. Seedlings with the DNA markers will be planted in the field, and their nuts will be evaluated as trees begin to bear. Selections with desirable nut and kernel traits will then be evaluated for EFB resistance in the greenhouse and in the field. In the second strategy, germplasm lacking the 'Gasaway' resistance gene will be evaluated for susceptibility to EFB. Germplasm exhibiting resistance will be incorporated into the breeding program as it is discovered. DNA markers for each new resistance gene will be identified for use in marker-assisted selection. The linkage map for hazelnut will be continually enhanced by adding new simple sequence repeat (SSR) loci. Dominant EFB resistance genes will be assigned to linkage groups based on linkage with mapped SSR loci. A draft genome of the Oregon isolate of the fungal pathogen will be obtained using two next-generation DNA sequencing approaches (Illumina and Roche 454). SSR and other types of markers will be developed from the draft sequence and used to distinguish fungal isolates. Documents SCA with OSU. Replacing 5358-22000-030-01S (9/04). Formerly 5358-22000- 030-02S (6/07). Formerly 5358-22000-034-01S (9/2009).
3. Progress Report
Nurseries are currently propagating new cultivars and advanced selections that combine the eastern filbert blight (EFB) resistance allele from 'Gasaway' and desirable nut characteristics, precocity and yield. 'Jefferson' (OSU 703.007) with complete resistance and large nut size was released as a replacement for 'Barcelona', and is being widely planted in the Willamette Valley. 'Jefferson' plantings include late-shedding pollinizers 'Eta' (OSU 984.075) and 'Theta' (OSU 1001.008). New cultivar 'Yamhill' (OSU 542.102), released in January 2008 for the kernel market, has complete resistance and high yield efficiency. Several buyers have expressed an interest in 'Yamhill' kernels. In vitro cultures of several promising selections are being established and maintained at the USDA Repository. To date, breeding efforts for EFB resistance have focused on the 'Gasaway' allele, but other sources of resistance are needed to ensure durable resistance to this disease. Additional resistant genotypes of European hazelnut have been identified and used in breeding, including "Weschcke hybrid" OSU 408.040, the Spanish cultivars 'Ratoli' and 'Culpla', a cultivar from the Republic of Georgia (Georgian 759.010), Russian selection OSU 495.072, and Serbian cultivar 'Crvenje'. Controlled pollinations have been made with good susceptible selections. Seedling populations segregating for resistance were scored for disease response in December 2008 and 2009. All of the new resistance sources appear to be controlled by single loci. The microsatellite markers developed by Kahraman Gurcan in his Ph.D. research have been used in fingerprinting and mapping. Four refereed journal articles were published from Kahraman's thesis. EFB resistance from OSU 408.040 maps to Linkage Group 3 (LG3), resistance from 'Ratoli' maps to LG7, and resistance from Georgian OSU 759.010 maps to LG2. Thus all are different from 'Gasaway' resistance (LG6) and each other. Selection OSU 1187.101, which originated from nuts purchased in the village of Holmskij (southern Russia), was found to be completely resistant to EFB. Two additional selections from nuts collected in southern Russia and three from the Crimea were completely resistant. Methods of ADODR monitoring included phone calls, e-mail and site visits.