Regeneration of doubled haploid plants by androgenesis of cucumber (Cucumis sativus L.)

Six experiments (including pretreatment, embryonic callus induction media, preculture conditions, embryo induction media, embryo germination media, and genotypic effects) were conducted to develop an efficient cucumber (Cucumis sativus L., 2n = 2x = 14) anther culture protocol. Pretreatment and embryo induction were key factors for successful anther culture. Suitable temperature stress depended on the ecotype, i.e., cucumbers from cold areas responded well to cold shock whereas those from temperate areas responded well to heat treatment. The best medium for embryonic callus induction was MS medium supplemented with 4.44 mu M BA, 2.26 mu M 2, 4-D, 4.64 mu M KIN, 3% sucrose and 0.8% agar. For embryo induction, MS medium supplemented with 0.54 mu M NAA, 13.32 mu M BA, 3% sucrose and 0.8% agar was optimal, and for embryo germination MS medium containing 2.22 mM BA, 6% sucrose and 1.2% agar was best. Using this protocol, we produced callus from 16 genotypes and regenerated plants from three of 20 evaluated. Three embryos per anther and 42 DH per 45 anthers (93% success) were obtained for cv. Ningjia No. 1, which was an improved result over a previous report. The origin of regenerants from microspores was determined by cytological, morphological and AFLP analyses.