Molecular diagnosis of phytoplasma infection in some Moldavian tomato varieties

Relevance. The use of molecular methods allows reliable and fast determination of the resistance of genotypes (varieties) to pathogens, thereby reducing possible product losses and, at the same time, maintaining its environmental safety. It is very important in conditions of increasing demand for high-quality agricultural production. Aim: Using molecular diagnosis of ʹCandidatus Phytoplasma solaniʹ to compare the degree of infection in some Moldavian tomato varieties at different stages of plant development.Material and methods. The molecular analysis (nested-PCR) of plants of the four Moldavian tomato varieties (Elvira, Cerasus, Mary Gratefully, Desteptarea) created at the Institute of Genetics, Physiology and Plant Protection, and the wild formSolanum habrochaites, was carried out for the presence of the phytopathogen ʹCa. P. solaniʹ. Researches were made during two growing seasons. Results. The distribution of infection between the studied varieties was different in the process of plants development. The spread of infection in the tomato field was recorded under the climatic conditions of two growing seasons: the season of 2018, which was hot but with normal rains in the middle of summer, and the season of 2019, in conditions of a very hot and dry summer. During both seasons, Cerasus variety manifested the highest resistance to ʹCa. P. solaniʹ infection.  A little more than half of plants of this variety were affected by stolbur only at the end of the growing season, after harvesting most of the crop. Varieties Elvira and Desteptarea had similar levels of infection of plants with phytoplasma during two years of research. These varieties manifested a higher sensitivity to phytoplasma infection compared with Cerasus. Mary Gratefully was the genotype with the highest dependence of the sensitivity toʹCa. P. solaniʹ infection from the climatic conditions of the growing season. Plants of the wild form Solanum habrochaites demonstrated complete immunity to phytoplasma infection during the growing season. Conclusion.The Cerasus variety, as well as the wild form Solanum habrochaites, can be recommended for including in breeding programs for the creating tomato varieties or hybrids resistant to phytoplasma. Thus, molecular diagnosis may be a useful tool for the breeding resistant genotypes.