The effects of plant growth regulators on in vitro gynogenic embryo formation in onion (Allium cepa L.)

Different combinations of plant growth regulators were tried on in vitro gynogenesis by flower bud and ovary culture for two open pollinated Turkish onion cultivars, “Bayram 1” and “Yakut” and a synthetic population of “OH-1”, which serves as a responsive control for extraction of gynogenic haploids of onion for two years (2011 and 2012). In 2011, modied Dunstan and Short (BDS) medium supplemented with 1 and 2 mg L-1 of 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzylaminopurine (BAP) and their combinations were used. Taking into account the first year results, combinations of 2 mg L-1 2,4-D and 1 and 2 mg L-1 of BAP were used in second year experiment. Auxin (2,4-D) and cytokinin (BAP) combined together induced callus development in two onion cultivars (Bayram 1 and Yakut), but haploid plants were obtained only from “OH-1” with 2 mg L-1 of 2,4-D and 1 mg L-1 of BAP combination. Results showed that genotype is more important factor for inducing in vitro gynogenesis than plant growth regulators.   Key words: Allium cepa L., gynogenesis, haploidy, onion.