Effect of low temperature on in vitro androgenesis of carrot (Daucus carota L.)

Low temperature (4A degrees C) is often applied to donor plants to induce androgenesis in subsequent anther culture. Material for Daucus carota L. (carrot) anther cultures was collected after 9, 12, and 21 d of cool treatment. The most effective treatment proved to be the use of 4A degrees C for 12 d, inducing 24.3 embryos per 100 anthers. Plants were regenerated from embryos, adapted, and then their ploidy and homozygosity were assessed. The analysis of ploidy performed by flow cytometry revealed that all plants obtained through androgenesis contained the amount of DNA corresponding to 2x chromosomes. When assessed for homozygosity, the population was found to consist mainly of homozygotes, 77.8% for glucose-6-phosphate isomerase (PGI, EC 5.3.1.9) and 75.0% aspartate aminotransferase (AAT, EC 2.6.1.1) which indicated the gametic origin of those plants. Distribution of homozygotes and heterozygotes did not depend on the applied thermal shock.