Cabbage (Brassica oleracea L. var. capitata) is an important leafy vegetable crop, and the development of homozygous parental lines is essential for F₁ hybrid breeding. Isolated microspore culture (IMC) provides a rapid approach for producing haploid and doubled haploid (DH) lines. However, its efficiency in cabbage remains highly dependent on genotype, donor plant growth conditions, and culture conditions. This study aimed to optimize key factors affecting microspore embryogenesis and plant regeneration in a Korean green cabbage (‘SJ-Ca 13’) and to evaluate the ploidy and genetic characteristics of regenerated plants. Microspore yield and embryogenesis were strongly influenced by flower bud size. Bud size of 4.0 ± 0.5 mm yielded the highest number of microspores (4.17 × 10⁴ per bud) and exclusively produced microspore-derived embryos (2.33 embryos per Petri dish), whereas smaller or larger buds failed to induce embryogenesis. Heat shock treatment at 32.5 °C was essential for embryogenesis, with 24 or 48 h of treatment inducing embryo formation, while prolonged exposure (72 h) completely inhibited embryogenesis. Efficient shoot regeneration was achieved when microspore-derived embryos were cultured on semi-solid MS medium with reduced salt strength (1/3×) and higher agar concentration (1.0%), resulting in the highest shoot regeneration rate. Ploidy test revealed that 50% of regenerated plants were spontaneous doubled haploids. SSR analysis using 26 markers detected no genetic polymorphism among regenerated plants. Overall, this study establishes an efficient IMC and regeneration system for cabbage and demonstrates its potential for rapid DH line production to support cabbage breeding programs.

Radish (Raphanus sativus L.), a root vegetable belonging to the Brassicaceae family, is considered one of the representative crops displaying sporophytic self-incompatibility (SSI). The utilization of a self-incompatibility system in F₁ breeding can improve the efficiency of cross-combinations, leading to a reduction in breeding time and aiding in the development of novel F₁ varieties. The successful implementation of this system necessitates the rapid and accurate identification of S haplotypes in parental lines. In this study, we identified a total of nine S haplotypes among 22 elite radish lines through Sanger sequencing. Subsequently, we obtained sequences for showing a 95% similarity to nine S haplotypes, along with sequences identified by other researchers using BLAST. Following this, multiple sequence alignment (MSA) was conducted to identify SRK and SLG sequence similarities, as well as polymorphisms within the class I and II groups. Subsequently, S haplotype-specific marker sets were developed, targeting polymorphic regions of SRK and SLG alleles. These markers successfully amplified each of the nine S haplotypes. These markers will play a crucial role in the rapid and precise identification of parental S haplotypes in the radish F₁ breeding process, proving instrumental in the radish F₁ purity test.

Radish (Raphanus sativus L.), a root vegetable belonging to the Brassicaceae family, is considered as one of the representative crops displaying sporophytic self-incompatibility (SSI). The utilization of a self-incompatibility system in F1 breeding can improve the efficiency of cross combinations, leading to a reduction in breeding time and aiding in the development of novel F1 varieties. The successful implementation of this system necessitates the rapid and accurate identification of S haplotypes in parental lines. In this study, we identified a total of 9 S haplotypes among 22 elite radish lines through Sanger sequencing. Subsequently, we obtained sequences for showing 95% similarity to 9 S haplotypes, along with sequences identified by other researchers using BLAST. Following this, multiple sequence alignment (MSA) was conducted to identify SRK and SLG sequence similarities, as well as polymorphisms within the class I, II groups. Subsequently, S haplotype-specific marker sets were developed, targeting polymorphic regions of SRK and SLG alleles. These markers successfully amplified each of 9 S haplotypes. these markers will play a crucial role in the rapid and precise identification of parental S haplotypes in the radish F1 breeding process, proving instrumental in the radish F1 purity test.

Sug-Youn Mo·Su A Oh·Soo Bin Choi·Han yong Park. J Plant Biotechnol 2025;52:215-22. https://doi.org/10.5010/JPB.2025.52.024.215

Han Yong Park ･You Kyoung Kim ･Soo Bin Choi ･Sug Youn Mo. J Plant Biotechnol 2023;50:82-8. https://doi.org/10.5010/JPB.2023.50.011.082