Filipkova N. Peculiarities of seed longevity formation and methods of long-term storage of maize hybrids

The dissertation presents a theoretical justification and a new solution to an important scientific and practical task, which is to develop new methods of long-term storage of maize hybrid seeds based on the principles of economic longevity and resource and energy conservation. The solution of this task allows us to stabilise maize seed production and build up stocks of high-quality seeds in the form of reserve, insurance and breeding seed funds. This dissertation topic is relevant given the need to investigate the phenomenon of maize seed longevity, the factors of its aging, and the development of effective methods for long-term storage of high-quality seeds. In addition to the scientific aspect, the relevance of this research is also related to the practical tasks to reduce energy and resource costs required for turnover of seed stocks. The known studies are incomplete and do not address the problem of long-term storage of high-quality maize seed stocks. The dissertation has resulted in new data related to the theory and practice of seed storage. The regularities of the formation of maize hybrid seed quality and longevity, as well as methods of reducing energy and resource costs required to turnover of seed stocks, have been established. The effect of methods and technological parameters of post-harvest processing on the quality and longevity of maize hybrid seeds was first revealed, and the technical and technological modes of drying, cleaning, sorting and calibrating seeds were optimised, which ensures the long-term seed storage. The main physical-mechanical, hydroscopic and physiological parameters related to the seed longevity during its processing and storage were determined. Methods and modes of long-term storage based on the combination of low moisture content, cooling and packaging of seeds have been established. For the first time, we identified the traits of seed health, such as acidity and the level of damage by surface microflora. The processes of drying, separating and chemical pre-sowing seed dressing aimed at preparing high-quality seeds of maize hybrids for long-term storage, as well as the storage process for maintaining the economic longevity of maize hybrids, and the seed quality control system at the post-harvest and storage stages have been improved. The theory of maize seed longevity based on its biological and technological quality diversity, as well as the concept of resource and energy conservation in the maize seed production system were further developed. The scientific novelty of the work lies in obtaining original results in addressing the problem of long-term storage of high-quality seeds, based on its theoretical background and practical conditions. The types of biological and economic longevity are theoretically substantiated. Longevity, in addition to biological, also has a technological nature, so a set of factors that have the greatest impact during harvesting, post-harvest processing and storage has been established. The biological factors include the botanical and biological characteristics of a given variety, hybrid, self-pollinated line. Technological factors include biotic, abiotic and anthropogenic factors that occur at the stages of maize cultivation, processing and storage.