Abstract:

Gynogenic embryos originating from unpollinated ovary culture were cultured on differentiation medium to induce homozygous autotetraploid cucumber. In total, thirty-three plantlets were regenerated, and seven were observed as autotetraploid (2n=4x=28) after chromosome counts. These autotetraploid plants were identified as homozygote after simple sequence repeat (SSR) analysis. Genetic stability of the progenies from self-crossing of these autotetraploid was studied, no ploidy variation occurred among these progenies after morphology and chromosome observation. Comparative studies were carried out between autotetraploid plants from ovary culture and autotetraploid plants from colchicines treatment, using parameters i-e, stainability of pollen grains, viability of pollen grains and number of seeds per fruit. Higher pollen fertility and number of seeds per fruit were found in the gynogenic induced autotetraploid plants. These results indicate that it is a method to induce autotetraploid through unpollinated ovary culture, and the obtaining of homozygous autotetraploid with higher fertility will be quite useful in cucumber breeding programs.

Key words: cucumber, Cucumis sativus L., ovary culture, autotetraploid