Basal media optimization for enhanced embryogenesis and doubled haploid recovery in onion (Allium cepa L.)

This study investigates the efficacy of Gamborg B5 and Murashige and Skoog (MS) basal media for enhancing embryogenesis and doubled haploid (DH) recovery in onion (Allium cepa L.) through ovary culture. Four genotypes (E604, E606, E611, E247) were evaluated for embryogenic response, shoot regeneration, and ploidy stability. Results demonstrated a fivefold higher embryo induction rate in B5 medium (5.41%) compared to MS (1.05%), with genotype E247 exhibiting the highest response (6.0%). B5 medium also outperformed MS in shoot regeneration, yielding 34 shoots versus 4 shoots, and produced a higher proportion of haploids (67.64%) and DHs (23.52%) as confirmed by flow cytometry. The superior performance of B5 is attributed to its optimized ionic composition and compatibility with monocot physiology, minimizing somaclonal variation. These findings highlight B5 medium as the preferred choice for efficient DH production in onion breeding, accelerating homozygous line development. However, genotype-specific variability underscores the need for tailored protocols. Future research should explore molecular mechanisms underlying B5’s efficacy and validate the field performance of regenerants. This study advances haploid technology in onion improvement, offering a cost-effective and rapid breeding solution.