Shaker-based microspore culture improves embryoid quality and regeneration efficiency in the production of doubled haploids from microspores of white cabbage (Brassica oleracea var. capitata)

Relevance. Doubled haploid (DH) technology enables accelerated breeding of homozygous lines in white cabbage; however, its efficiency is limited by genotype dependency. Optimizing culture conditions, including the use of a shaker platform, may enhance embryoid yield and regeneration potential. Methodology. We studied three white cabbage genotypes (No. 2502, 2503, and 2504). Microspores were cultured under both static and shaking conditions (40-50 rpm) for 30 days. On day 30, we assessed the developmental stages of the embryoids. After that, the embryoids were transferred to a regeneration medium and, after three months, we recorded successful regeneration into fully developed plants. Results. Shaker culture significantly increased the proportion of cotyledonary-stage embryoids (up to 81.7 % in genotype 2502) and reduced the frequency of abnormalities (down to 0 % in genotype 2503). Overall embryoid regeneration capacity under shaker conditions was 30.5 ± 5.4 %, compared to 19.2 ± 2.8 % under static conditions. Cotyledonary embryoids produced on the shaker showed the highest regeneration efficiency (36.5 %). These findings support the implementation of shaker-based culture in DH protocols for white cabbage to improve overall efficiency.