The effect of culture media, explants and genotypes on adventitious shoot regeneration in spring rapeseed (Brassica napus L.) was examined. Hypocotyls and cotyledons of the doubled haploid lines NL-611, NL-662, NL-685 were induced to form callus by culturing on the Murashi geSkoog medium supplemented with different concentrations of 6-benzylaminopurine (BAP) and α-naphtylacetic acid (NAA) or zeatin and 2,4-dichlorphenoxyacetic acid (2,4-D). Adventitious buds were regenerated from the organogenic callus on the same medium. A large variation of shoot regenerability was observed, ranging within 0-37.5% for the frequency of bud formation and within 0-3.8 for the number of buds per explant. Generally, cotyledon-derived callus exhibited a higher bud regeneration frequency than hypocotyls, however, hypocotyl-derived callus developed a higher number of buds per explant. The maximum number of adventitious buds from hypocotyl-derived callus was obtained on a medium supplemented with 4.0 mg l -1 BAP and 0.05 mg l -1 NAA. Regenerated shoots were rooted in MS medium containing 0.1 mg l -1 NAA. Well rooted plantlets were acclimatized and subsequently established in soil.

Breeding linseed (Linum usitatissimum L.) using haploid techniques allows breeders to develop new cultivars in a shorter time period. Many research groups successfully created new linseed genotypes through anther culture; however ovary culture has been the subject of only a few earlier studies. In the present study, the effect of genotype and growth regulators combination on callus induction and shoots regeneration in ovary culture of nine commercially important linseed cultivars was investigated. Ovaries were cultured on modified MS medium supplemented with three different combinations of plant growth regulators. Variable callogenic responses were expressed by all of the genotypes tested on different induction media. The results suggested that specific combination of growth regulators for callus induction must be designed for each genotype. Shoot regeneration from ovary derived callus is a critical phase of the whole gynogenetic process. Differences in adventitious shoot formation frequency among genotypes were demonstrated and four responsive genotypes have been selected. Ovary derived callus from cultivar 'Mikael' manifested the highest adventitious shoot formation frequency with a high number of shoots per explant. The optimum ratio of growth regulators for shoot regeneration was shown to depend on the genotype. Cultivars 'Linola', 'Mikael' and 'Szaphir' showed the highest shoot regeneration frequency when callus had originated on induction medium supplemented with 2 mg L −1 BAP and 2 mg L −1 NAA, while combination of 1 mg L −1 BAP and 2 mg L −1 IAA promoted shoot formation in ovary-derived callus of 'Barbara'. The highest rate of shoots per explant has been obtained in second subculture.