Onions (Allium cepa L.) are a globally significant horticultural crop, ranking second only to tomatoes in terms of cultivation and consumption. However, due to the crop’s complex genome structure, lengthy growth cycle, self-incompatibility, and susceptibility to disease, onion breeding is challenging. To address these issues, we implemented digital breeding techniques utilizing genomic data from 98 elite onion lines. We identified 51,499 high-quality variants and employed these data to construct a genomic estimated breeding value (GEBV) model and apply machine learning methods for bulb weight prediction. Validation with 260 new individuals revealed that the machine learning model achieved an accuracy of 83.2% and required only thirty-nine SNPs. Subsequent in silico crossbreeding simulations indicated that offspring from the top 5% of elite lines exhibited the highest bulb weights, aligning with traditional phenotypic selection methods. This approach demonstrates that early-stage selection based on genotypic information followed by crossbreeding can achieve economically viable breeding results. This methodology is not restricted to bulb weight and can be applied to various horticultural traits, significantly improving the efficiency of onion breeding through advanced digital technologies. The integration of genomic data, machine learning, and computer simulations provides a powerful framework for data-driven breeding strategies, accelerating the development of superior onion varieties to meet global demand.

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.