Krystyna Górecka

Microspores were cultured on the modified B₅ liquid medium containing 2.4D (0.1 mg L⁻¹), NAA (0.1 mg L⁻¹), L-glutamine (500 mg L⁻¹), L-serine (100 mg L⁻¹), and sucrose (100 g L⁻¹). The developmental stages of microspores and divisions were observed. Initially, the formation of binuclear and multicellular structures was noticed. Plants regenerated in the cultures in which the tetrad stage of microsporogenesis had predominated. Embryoids were still forming 24 weeks after the cultures were set up. Six weeks after the transfer of androgenetic embryos onto the B₅ regeneration medium, they were converted into complete plants. Out of 90 androgenetic plants planted in a growth chamber, 42 plants adapted to the new conditions. All of those plants proved to be diploids in cytometric analysis.

Regeneration and Evaluation of Androgenetic Plants of Head Cabbage (Brassica Oleracea Var. Capitata L.): Plant regeneration from head cabbage embryos obtained in anther culture, the way of colchicine using for doubling number of chromosomes in haploid plants and estimation of the double haploid plants with regard to vigour, typicality of leaves and fertility were worked out. The best medium for plant regeneration from androgenetic embryos was B5 medium, enriched with sucrose 20 g.L^-1 and kinetin 20 mg.L^-1. On this medium, the highest number of embryos formed shoots, usually several from 1 embryo, particularly in subsequent passages. The most effective method of doubling the number of chromosomes was soaking the roots of young plants, when they had 5-6 leaves in a 0.1% hydrous solution of colchicine with 4.0% DMSO and 25 ppm GA₃, for 20 hrs. The tested cultivars of head cabbage differed considerably with regard to the vigour of the plants obtained from anther culture. The highest number of plants characterized by strong vigour was observed in the cultivar Langendijker. About 90% of head cabbage plants obtained from androgenetic embryos had typical leaves and the differences between the cultivars in this aspect were insignificant. The highest number of androgenetic androfertile plants was found in the cultivar Sława z Enkhuizen. The genotype was the factor which had an impact in the processes examined: ability to shoot proliferation, rooting, the sensitivity to colchicine treatment, vigour of produced doubled haploid plants and their fertility.