No abstract

Doubled haploid lines of carrot can be obtained through androgenesis in anther cultures and in isolated microspore cultures. The two methods were compared using three carrot cultivars ('Kazan F1' , 'Feria F1' , and 'Narbonne F1') at the androgenesis induction stage, during plant regeneration from embryos, and during acclimatization of androgenetic plants as well as their characterization. It was found that cultivar was the main factor affecting the efficiency at each stage of plant production in both anther and isolated microspore cultures. The efficiency of androgenesis in anther cultures of 'Feria F1' was considerably higher in comparison with isolated microspore cultures, and more plants were obtained from the embryos of androgenesis-cultured plants. In 'Kazan F1' and 'Narbonne F1' , more acclimatized androgenetic plants were produced from anther cultures. Ploidy assessment of acclimatized plants of 'Narbonne F1' showed that the majority of the plants in the population derived from anther cultures had a doubled chromosome (DH) set. On the other hand, the majority of plants obtained from isolated microspore cultures were haploids. When assessing homozygosity, it was found among plants obtained in anther cultures that the percentage of homozygotes for phosphoglucose isomerase (PGI) and aspartate aminotransferase (AAT) depended on the cultivar. In contrast, the majority of plants derived from isolated microspore cultures were homozygous regardless of cultivar.

This study examines the influence of the polyamines putrescine and spermidine on the efficiency of androgenesis in anther cultures of 2 carrot cultivars, Kazan F 1 and Narbonne F 1 , and the effect of putrescine on the process of plant regeneration from androgenetic embryos. In the Kazan F 1 variety, an increase in the number of obtained embryos was achieved using each of the 2 polyamines separately and in combination. In contrast, no beneficial effects of polyamines on the efficiency of androgenesis were observed in the Narbonne F 1 variety. Putrescine added to the regeneration medium increased the number of obtained plants. For embryos obtained on induction medium without putrescine, the best concentration was 160 mg putrescine in 1 L of regeneration medium, and for those obtained on the induction medium with putrescine the best concentration was 0.5 mg putrescine per 1 L. All of the resulting plants, both in the experimental and control combinations, had a doubled set of chromosomes. The vast majority of them were homozygous for both isoenzymes, glucose-6-phosphate isomerase and aspartate aminotransferase, and the distribution of homo-and heterozygous received combinations with the polyamines and in the control was very similar.