Variability and heritage of the reaction of promising tomato lines to high temperatures

Relevance. In the Republic of Moldova in recent years, during tomato flowering, air temperature reaches 35°С and higher, which significantly reduces fruit set, yield and product quality, therefore, the creation of varieties resistant to temperature stress is of particular importance. The relevance of the studies is due to the need to identify tomato genotypes resistant to high temperatures, to identify the genetic nature of the variability and degree of inheritance of tomato growth organs when interacting with different temperature conditions. The purpose of the research is to determine the effect of stress temperatures on the organs of growth and development of tomato plants at an early stage of ontogenesis, the degree of genetic, phenotypic variation and inheritance of characters. Materials and methods. The research material was 5 promising lines of tomato with high economically valuable traits. As a standard, a omologated variety Mary Gratefully was used. Four temperature levels were used – optimal (25°С) and stress (38, 40 and 42°С). The length of the germinal root and stem of 7-day-old plants was measured. The experiment was made in 3 replicates. The following were studied: genetic and phenotypic variants, heritability coefficient, phenotypic and genotypic coefficients of variation, genetic progress. The data were processed in the STATISTICA 7 software package. Results. As a result of the studies, a significant differentiation of the reaction of tomato genotypes to temperature stress was revealed. A significant effect of temperature on the genetic and phenotypic varieties of signs of growth and development of tomato plants, heritability in the broad sense, genotypic and phenotypic coefficient of variation, and genetic progress have been established. Of a great interest for further studies are the Mary Gratefully, L 304, L 306 genotypes, which are highly resistant to the studied traits.