Determination of incompatibility S-alleles and relationships among them in F1 progenies of two cultivars of hazelnut (Corylus avellana L.)

Incompatibility in hazelnut (C. avellana L.) is the sporophytic type and under the control of a single S-locus with multiple alleles. Compatibility of pollen-stigma in hazelnut is an important consideration in planning crosses in breeding program and in choosing pollinizers for orchard planting. In this study، fluorescence microscopy was used to determination of S-alleles and compatibility relationships among in 24 progeny of TGL × Cosford. Four pollen testers، selected for each one of the four alleles under investigation (S2، S3، S7 and S11). When stiminate catkins elongated and were about to shed pollen، they were collected and dried. The catkins were discarded، pollen collected and stored in freezer (-20 0C). In each seedling trees، two branches emasculated، and bagged. Female clusters were detached from bagged limbs، when style protrude 2-6 mm. Five clusters from each seeding progeny pollinated with each pollen testers. About 20 to 24 hours after pollination، the stigmatic styles were detached from buds and squashed in aniline blue dye and examined with fluorescence microscope (40x and 100x). In this research، S-alleles determined in 22 progenies. However in two progenies، distinguished only one S-allele. In a compatible pollination، pollen germinates well، the pollen tubes penetrate the stigmatic surface and produce a mass parallel tubes. But in incompatible reactions، pollen germination was often reduced، and pollen grains that germinate produced short tubes.