Effect of Various Stress Factors on the Induction of Androgenesis in Anther Cultures of Brussels Sprouts (Brassica oleracea L. var. gemmifera)

Six cultivars of Brussels sprouts were used in the experiments: Ajax F₁, Diablo F₁, Icarus F₁, Maximus F₁, Topline F₁, Philemon F₁. Three experiments were set up to study the effect of 3 stress factors on the induction of androgenesis: ‘warm’ (+35°C) thermal shock (stress), ‘cold’ (+4°C) thermal shock (stress), and stress caused by the cutting-off of the top ends of anthers before they were laid out on the induction medium. The obtained androgenic embryos of Brussels sprouts were used to regenerate shoots on medium B5 (Gamborg et al. 1968) with 20 mg·L^-1 kinetin and 20 g·L^-1 sucrose, which were then induced to take root on medium B5 containing 1 mg·L^-1 IAA and 30 g·L^-1 sucrose.

The ‘warm’ (+35°C) shock for 24 hours proved to be an effective stimulus for inducing androgenesis in anther cultures of Brussels sprouts. The ‘cold’ (+4°C) thermal shock was less beneficial. Extending the time of treatment with low temperature (to 48, 96, and 144 hrs) was also less effective than the +35°C ‘warm’ shock for 24 hours. Differences were found in the response of the cultivars, and even clones, to the types of shocks employed. For Maximus F₁ - the less embriogenic cultivar - the most beneficial stimulus proved to be the cutting-off of the top parts of anthers prior to setting up cultures.

As a result of the three passages, from each surviving embryo the authors managed to obtain a number of plants sufficient for carrying out further stages of the breeding process.