Polyploidization Facilitates BiotechnologicalIn VitroTechniques in the GenusCucumis

Abstract

Prezygotic interspecific crossability barrier in the genusCucumisis related to the ploidy level of the species (cucumber (C. sativus), ; muskmelon (C. melo) and wildCucumisspecies, ). Polyploidization of maternal plants helps hybridization among otherCucumisspecies by overcoming prezygotic genetic barriers. The main objective of this paper is to compare the results of several methods supporting interspecific crosses in cucumber without and with polyploidization (comparison between diploid (2x) and mixoploid (2x/4x) cucumber maternal plants). Mixoploid plants were obtained afterin vivoandin vitropolyploidization by colchicine and oryzalin. Ploidy level was estimated by flow cytometry. Embryo rescue,in vitropollination, and isolation of mesophyll protoplast were tested and compared. Positive effect of polyploidization was observed during all experiments presented by higher regeneration capacity of cultivated mixoploid cucumber embryos, ovules, and protoplasts. Nevertheless, the hybrid character of putative hybrid accessions obtained after crossin vivoandin vitropollination was not confirmed.