Effects of methylene blue on microspore embryogenesis and plant regeneration in ornamental kale (Brassica oleracea var. acephala)

•This study aimed to develop an effective method to induce embryogenesis and to regenerate kale doubled haploid plants by treatment of microspore cultures with Methylene blue, whereby the time for breeding new hybrids may be significantly shortened.•In this paper, ploidy, self-incompatibility and uniformity of DH lines were analyzed, and only showed a slightly change.•All of the genotypic groups showed a good performance, which complying with the standard of hybrid seed production.