Gynogenesis in Polish onion cultivars

During the two years of the studies (1997-1998) 32802 flower buds of thirty Polish onion genotypes were plated on different media. In total 310 embryo s (0.9%) were obtained, out of which more than a half underwent regeneratio n. It was established that 3.5-4.5 mm long flower buds were the most respon sive to gynogenesis. Out of 6 studied media combinations the highest yield of gynogenic embryos was produced on the B5 or BDS media containing 2.0 mg/ L 2,4-D and 2.0 mg/L 6BA (denoted as A1 and F6 induction media, respectivel y) followed by the R regeneration medium (BDS supplemented with 1.0 mg/L NA A and 2.0 mg/L 2iP). It was observed that the cultivars differed with regar d to their demands for media composition. The yield of embryos strongly dep ended on the genotype. For 9 genotypes the induction of gynogenesis failed, 12 genotypes yielded 0.2-0.8% embryos, eight produced 1.0-4.3% embryos whi le only one gave 10.0% embryos.