Gametic embryogenesis through isolated microspore culture in Corylus avellana L.

Haploid technology is a valuable plant breeding tool for obtaining homozygosity particularly in woody plants. Hazelnut, the world’s sixth ranking nut tree crop is a monoecious, anemophilous species. It is characterized by a sporophytic incompatibility system that prevents production of homozygous plants with conventional methods, involving several self-pollination cycles. In this study, gametic embryogenesis, in particular isolated microspore culture, was tried with five genotypes. Two culture media were tested and four temperature stress treatments were applied to the isolated microspores that were cultivated at the vacuolated developmental stage. To our knowledge, this is the first report of early embryos being recovered from the five hazelnut genotypes via isolated microspore culture. Analysis of the embryo genotypes using SSR markers demonstrated the embryos had a single allele per each locus whereas the parent cultivar was heterozygous, indicating they developed from haploid microspores. The response to the culture treatments, was, however, genotype-dependent, as previously reported for male gamete embryogenesis in other fruit crops.