Morphogenetic peculiarities of reproductive biology in sugar beet (Beta vulgaris L.) breeding

This review considers the processes of morphogenesis used in the development of propagation methods and the creation of a new starting material for sugar beet. It has been demonstrated that methods of particulation, in vitro microcloning and cell breeding that reflect non-sexual forms of plant reproduction increase the effectiveness of breeding experiments. The review describes the in vitro culture methods maintaing a tendency in plants for vegetative propagation and stimulating increase in genetic variability of properties when mutagens such as ethyl methanesulfonate, alien genetic structures with mf2 and mf3 bacterial genes in Agrobacterium tumefaciens strains, and selective agents (Сd++ ions and abscisic acid) are incorporated into plant cells. It presents the results of using fluorescent microscopy, cytophotometry, biochemical analysis and determining the level of phytohormones and content of nucleic acids in nuclei for forecasting the seed setting ability. It has demonstrated that long self-pollination of plants causes decrease in fertility of pollen grains, resulting in the sterilization of male gametes and the appearance of pistillody flowers. Self-fertile plants isolated from these lines serve as sterility fixers, while the apomixis elements increased the ovule number, additional embryo sacs and embryos. A role of apomixis in contributing to variability in the ontoand phylogenetic development of plants have been substantiated. The review reflects the morphological features of the in vitro development of sexual and somatic cells in embryos during the formation of seedlings based on floral and vegetative embryoidogeny. Use of the SNP and SSR (Unigenes) molecular-genetic markers having a high polymorphism level has appeared effective to characterize the developed breeding material and hybrid components when carrying out crossings. The study of sugar beet starting materials for the presence of TRs mini-satellite loci making it possible to reveal O-type plants-pollinators (sterility fixing agent) and MS-form plants are of interest for breeding as well. The selected material can be widely used in breeding to produce hybrids, allowing for a 2–3-fold reduction of the development period. The review also discusses the prospects for the development and implementation of new methods and original schemes in sugar beet genetics, biotechnology and breeding

Biotechnological methods as a tool for efficient sugar beet breeding

Here we consider aspects of the application of biotechnological methods to rapid creation, propagation, and maintenance of plants with improved or new traits in sugar beet breeding. The results of the works carried out in these fields by the Federal State Budgetary Scientific Institution "The A.L. Mazlumov All-Russia Research Institute of Sugar Beet” are reviewed. A close association between morphological and physiological changes in in vitro cultured organs and tissues, on the one hand, and breeding traits, on the other hand, which allows the development of experimental systems for non-amphimictic plant reconstruction is shown. The influence of in vitro growth conditions on haploid cells of unfertilized sugar beet ovules in the course of obtaining doubled haploid lines with high degree of homozygosity and maintenance of valuable breeding properties is considered. As compared to common inbreeding, this method shortens the time for development of homozygous material from 10-12 to 3-5 years, which is of great importance for speeding-up the breeding process. The results of studies on the culturing of mature sugar beet zygotic embryos based on in vitro selective systems have made it possible to improve the adaptive potential of plants and to provide complex resistance to environmental stress factors. Strict selection under abiotic stress conditions allowed creation of sugar beet isogenic lines with tolerance of drought, salinity, and soil acidity. It is shown that the proposed original design of mass-scale microclonal in vitro reproduction and deposition of elite plants as components of highly productive hybrids can be used to obtain seeds of uniform high-quality breeding material. The technologies developed by biotechnological methods are a topical and innovative direction of inquiry, since the application of these techniques to sugar beet breeding will promote obtaining of competitive hybrids with a set of commercially valuable traits. The combination of biotechnology methods, including tissue culture, and traditional breeding techniques is expected to provide an opportunity to obtain a new starting material to develop domestic varieties and hybrids of new generation with heterosis effect and a wide resistance spectrum persisting across generations