|Abstract or Summary
- Eastern filbert blight (EFB), caused by Anisogramma anomala (Peck) E.
Miiller, is a devastating disease to orchards of the European hazelnut (Corylus
avellana L.) in the Willamette Valley, Oregon. Host resistance is the most
desirable means of disease control. Fifty-eight hazelnut accessions, including
European cultivars and interspecific hybrids were evaluated for their response to
eastern filbert blight following greenhouse inoculation using an enzyme-linked
immimosobent assay (ELISA) and visual inspection. Of the fifty-eight accessions,
forty-four showed infections, twelve remained free of infection and two gave
inconclusive results. The twelve accessions showing complete resistance to the
disease are: European hazels 'Culpla' from Spain and 'COR 187' from Finland;
C. americana x C. avellana hybrids 'COR 506', 'G081S' and Weschcke selections
TP1, TP2 and TP3; C. columa x C. avellana hybrids Chinese Trazel Gellatly #6
and #11, Turkish Trazel Gellatly #3 and a [(C. columa x C. avellana) x C.
avellana] backcross hybrid 'Lisa'; and a C. heterophylla var. sutchuensis x C.
avellana hybrid 'Estrella #1'. These new sources of complete resistance can be readily crossed to European cultivars and thus useful in the hazelnut breeding
OSU 408.040 showed complete resistance in a previous study and appears
to be a new source of resistance apart from 'Gasaway'. Segregation analysis of
three progenies from crosses with susceptible genotypes [97035 (OSU 245.098 x
OSU 408.040), 97036 (OSU 474.013 x OSU 408.040) and 99035 (OSU 665.012 x
OSU 408.040)] indicated that a single gene controls the resistance. AFLP
methodology was employed to identify markers linked to EFB resistance in OSU
408.040. A total of 64 primer combinations were screened using progeny 97035.
Five AFLP markers linked in coupling, to resistance were identified, with
recombination as shown: A4-265 (9.2 cM), A8-150 (0.0 cM), B2-125 (4.1 cM),
C2-175 (5.9 cM) and D8-350 (2.5 cM). B2-125 was located on one side of the
resistance locus and A4-265, C2-175 and D8-350 on the other side. Three of these
markers (B2-125, C2-175 and D8-350) were also linked in coupling in a similar
order in the second population 97036. The markers identified in this study are the
first step toward marker-assisted selection for the OSU 408.040 source of
A Spanish cultivar 'Ratoli' showed complete resistance in a previous study
and also appears to be a new source of resistance. Segregation analysis of two
progenies [99035 (OSU 309.074 x Ratoli) and 99036 (OSU 665.012 x Ratoli)]
indicated that 'Ratoli' transmitted resistance to 67% of its progenies. AFLP
methodology was employed to identify markers linked to EFB resistance in 'Ratoli'. A total of 64 primer combinations were screened using progeny 99036.
Two AFLP markers linked to Ratoli resistance were identified with recombination
as shown: dAl-135 (13.7 cM) and C4-255 (4.2 cM). Marker dAl-135 is linked in
repulsion to the resistance locus, whereas, C4-255 is linked in coupling. C4-255
and dAl-135 are on the same side of the resistance locus. One of the markers C4-
255 was present in the second population 99035. Further effort is needed to find
additional markers closely linked to the resistance locus in 'Ratoli'.