GENETICALLY STABLE SOMATIC EMBRYOS OF F1 CUCUMBER (CUCUMIS SATIVUS) HYBRIDS
Explants were taken from hypocotyls, cotyledons and leaves of five cucumber cultivars. The maximum callus weight in the induction medium was 1215.4 mg with the cv. Natica using hypocotyl explants and the minimum was 487.6 mg with cv. Mascot using leaf explants. When auxin was available in the induction phase somatic embryos were obtained; the absence of cytokinin caused a reduction in the number of embryos. The number of somatic embryos increased with sucrose concentration to a maximum of 9% sucrose. Three weeks on induction medium was needed for production of somatic embryos; prolonged incubation (6 weeks) gave poor somatic embryo numbers. As auxin concentration decreased in maturation medium somatic embryo yield increased; the highest number was obtained in the absence of auxin. Generally, the culture of callus on maturation medium in darkness was superior to 16 h light for somatic embryogenesis. Leaf explants of the cultivar Profito gave 37.3 embryos per replicate which was the highest number recorded. In addition, this cultivar yielded embryos in the shortest time period (6 weeks). Satisfactory somatic embryo numbers were obtained after three weeks on induction medium, plus three weeks on maturation medium, or four weeks on induction medium, plus two weeks on maturation medium, or five weeks on induction medium, plus one week on maturation medium. Comparison of characteristics of cucumber plants derived from somatic embryogenesis with those obtained from seed showed no significant difference in phenotype of plants, or fruits, or genotype (using RAPD DNA tests).
Suliman Elmeer, K.M. and Hennerty, M.J. (2007). GENETICALLY STABLE SOMATIC EMBRYOS OF F1 CUCUMBER (CUCUMIS SATIVUS) HYBRIDS. Acta Hortic. 764, 49-56
somatic embryogenesis, callus formation and RAPD