Obtention of Embryos and Plants from In Vitro Culture of Unfertilized Ovules of Cucurbita pepo 

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Cucurbit Genetics Cooperative Report 8:66 (Article 24) 1985

Chambonnet, D. and R. Dumas de Vaulx
Institut National de la Recherche Agronomique, 84140 Montfavet, France

Unfertilized ovules of Cucurbita pepo have been in vitro cultured to obtain haploid plants from the embryo-sac cells. In our first experiments we obtained embryos coming from the internal part of the ovule without callus formation. The best results were obtained in culturing ovules excised one or two days before flowering. At this stage the ovules are not fertilized. The most efficient culture media were very similar to those used in our laboratory for pepper and eggplant anther culture (2,3). Under optimal conditions we could obtain the regular mean rate of 4 to 7 plants per 100 cultured ovules. The embryos directly gave plantelets after transfer to an hormone-free medium (1). Plants were then transplanted to soil.

Most of the plants were diploids but some were haploid-diploid chimeras, aneuploids or polyploids. The genetic analysis of the diploid plants is underway. Plants obtained from 8 heterozygous F1 cultivars were not similar to the mother donor plant. From each F1 cultivar, the regenerated plants showed different phenotypes. So, they did not come from maternal tissues. The first selfed progenies were observed and seemed homogeneous.

Further studies are under progress for:

  • increasing the embryo production
  • obtaining plants from different cultivars
  • genetical and cytological analysis

Literature Cited

  1. Dumas de Vaulx, R. and M. Pitrat. 1980. Application de la culture
    d’embryons immatures a la realisation de l’hybridation interspecifique
    entre Cucurbita pepo et C. ecuadorensis, F1 et BC1. Reunion Eucarpia
    “Applications de la culture in vitro a l’amelioration des plantes
    potageres”, Versailles, France, 126-130.
  2. Dumas de Vaulx, R., D. Chambonnet and E. Pochard. 1981. Culture in vitro
    d’antheres de piment (Capsicum annuum L.): amelioration des taux
    d’obtention de plantes chez differents genotypes par des traitements a
    +35°C. Agronomie, 1:859-864.
  3. Dumas de Vaulx, R. and Chambonnet, D. 1982. Culture in vitro d’antheres
    d’aubergine (Solanum melongena L.): stimulation de la production de
    plantes au moyen de traitements a +35°C associes a de faibles teneurs
    en substances de croissance. Agronomie, 2:983-988.