The influence of different factors on microspore embryogenesis in Chinese cabbage ( B. rapa ssp. chinensis) was studied. A genotype dependence for embryo formation was observed. The majority of...

Turnip is a biennial crop and, consequently, the creation of pure lines for breeding is a time-consuming process. The production of pure turnip lines using doubled haploids produced in isolated microspore culture has not been sufficiently developed. The aim of the present work was to determine some key factors inducing embryogenesis in the isolated microspore culture of turnip, as well as investigating the manners of embryo development. It was shown that the acidity of the medium is an important factor in embryo production; different optimal pH levels ranging from 6.2 to 6.6 corresponded to individual genotypes. Such factors as the cold treatment of buds and the addition of activated charcoal to the nutrient medium increased the responsiveness of all genotypes studied. The turnip variety ‘Ronde witte roodkop herfst’ demonstrated a genetic disorder in the development of microspores; namely, non-separation of some microspores from tetrads. In the in vitro culture, each of the daughter microspores developed on its own. This indicates the dependence of the possibility of embryogenesis in the turnip microspore culture on the genotype. Results suggest that the initiation of secondary embryogenesis in primary embryos leads to an increase in the proportion of doubled haploid plants.

Antibiotics are widely applied for plant cultivation in vitro to eliminate bacterial contamination. However, they can have both positive and negative effects on the cells of cultivated plants, and these effects largely depend on the type antibiotic used and its concentration. The objective of the present study was to estimate the effect of β-lactam antibiotics ampicillin (Amp) and cefotaxime (Cef) on microspore embryogenesis induction in vitro in the Brassica species. The performed experiments confirmed cefotaxime inhibits microspores in B. napus and B. oleracea, even in concentrations as low as 50 mg/L. The highest embryo yield was obtained for B. napus in the NLN-13 medium with added ampicillin in concentrations of 50–100 mg/L as an antimicrobial agent. This embryo yield was significantly higher than that obtained in a medium without supplemented antibiotics and two times higher than in the medium with added cefotaxime. Analogous results were obtained for B. oleracea and B. rapa.

Relevance One of the basic directions of the cabbage crop breeding is the creation of F₁ hybrids with a complex of economically valuable traits. This process is difficult and time-consuming as to get pure lines must be within 6-12 years hold inbreeding. Herewith not every line gives the desired heterotic effect that also requires additional verification. Methods Biotechnological method culture of isolated microspores in vitro, which allows in the first generation to receive a line with 100% homozygosity, was used to speed up the breeding process. Combination ability were performed in complete diallel cross on the basic morphological signs. Results Culture medium for cultivation of isolated microspores in vitro was optimized for each genotype of cabbage for the best embryoids regeneration. Maximum amount of embryoids was received on medium with pH 6.2 using ampicillin 100 mg/l and zeatin 1 mg/l: 466.7 ± 153.2 PCs/100 buds. A new source material for breeding – doubled haploid lines of cabbage was received. Lines – the best parents for F₁ hybrids with high yield, compact rosette of leaves, with optimum inside and short outside cabbage stump was created. Studies have shown that optimization of breeding process in case of creation of pure lines of cabbage in 3 years with microspore culture requires to reduce the breeding process in 2 times.

Relevance. Pepper is a common crop both for fresh consumption and for the preparation of spices. Recently, along with the increasing popularity of C. annuum L. pepper, there is increasing interest in other species of this genus, which have a number of breeding and important properties. The most important method of enriching the gene pool of cultivated plants is distant hybridization, through which valuable traits are transferred from wild species to cultivated ones. The development of a new variety is a lengthy process, stretching over several years. In this regard, breeders have faced the challenge of obtaining pure lines to create a pepper hybrid with desired properties by applying modern biotechnological methods that will accelerate this process. One of them is the method of microspore culture, which allows mass production of haploid plants, reducing the time for creating constant parental lines.Material and methods. The aim of the work was to create an interspecific hybrid of hot pepper (C. annuum L. x C. frutescens L.) with high ornamental properties, a complex of economically valuable traits, with good taste qualities. The research was carried out in the film greenhouse of FSBSI FSVC in the Moscow region. The research material was a variety population of hot pepper Capsicum frutescens Cz-544-14, used as a paternal line, which was heterogeneous, and a pure line of C. annuum L. (Pb-551) created by classical breeding.Results. The pepper hybrid F1 Christmas bouquet was created as a result of hybridization of species parental forms obtained by different methods (biotechnological and classical). To accelerate the production of an aligned paternal form of C. frutescens L., the technology of doubled haploids through microspore culture was used. As a result, doubled haploid plants meeting the planned model (compact low habit, purple fruit colouring in technical ripeness and red in biological ripeness) were obtained. The resulting hybrid combined all the necessary economic features: high ornamentality, compactness, bouquet arrangement of fruits, high taste and aroma. Thus, the use of remote interspecific hybridization in the breeding process in combination with biotechnological approaches can accelerate the production of new forms of hot peppers that meet the demands of the market.