In vitro ovary culture of cucumber (Cucumis sativus L.) for haploid plant production

In order to produce haploid plants through ovary culture in cucumber (Cucumis sativus L.), a factorial experiment based on randomized design was conducted with three replicates under in vitro conditions. The ovaries of Sina, a hybrid variety of cucumber were harvested one week after flowering. They were cultured in the MS medium containing different concentrations of (0, 0.8 and 1.2 mg/L) TDZ and BAP, respectively. The best calli and the highest percentage of calli were obtained in the culture medium containing 0.8 mg/L TDZ and BAP. Then, 3 week-old explants were transferred to the differentiation medium; MS medium, supplemented with NAA, IBA, IAA, 2,4-D, Pic at 0.05 mg/L and 3 cytokinins including TDZ, BAP, Kin with 0.5, 1 and 1.5 mg/L, respectively, with a total of 15 treatments and 3 replicates. They were subcultured once every two weeks. The highest percentage of callus formation was obtained in the presence of 0.05 mg/L NAA and 1.5 mg/L TDZ. The highest percentage of embryogenesis (93.33%) was observed in the presence of IAA at 0.05 mg/L and 0.5 mg/L Kin. Application of IBA at 0.05 mg/L with 0.5 mg/L Kin increased the embryogenic calli formation. Also, the highest regeneration percentage (83.33%) was found in all 4 treatments including 0.05 mg/L IBA, with 0.5 mg/L TDZ, 0.05 mg/L IBA with 0.5. 0 mg/L BAP, 0.05 mg/L 2,4-D with 1.5 mg/L BAP and 0.05 mg/L Pic, with 1.5 mg/L BAP. After transferring the explants to the second step culture media, the embryo-like structures (ELS) developed into plantlets. Finally, complete plantlets were obtained after rooting the plantlets on the MS medium with no supplement. In addition, the results of chromosome counting showed that among 10 regenerated plantlets, one plantlet was haploid, and 9 plantlets were diploid.