The breeding method and its influence on the intensification of the tomato selection process

Relevance. The article presents the results of using three different selection methods to obtain new forms of tomato that combine high productivity with resistance to high-temperature stress factor. Methods. Eleven hybrid combinations were used as experimental material. Selections were made starting with the offspring of the F1 generation. Three different methodological approaches were used: 1 - step-by-step alternation of sporophytic-gametophytic selections under high temperature pressure; 2 - only gametophytic selection using heat-treated pollen for pollination; 3 - traditional selections based on a high value of indicators of the studied traits. In each of the variants of the experiment, we studied: the heat resistance of offspring at different stages of ontogenesis -"sporophyte-gametophyte"; the duration of the vegetation period of plants; the fruit formation; the total yield. The offspring of the most stable and productive plants isolated from different hybrid combinations were combined in the populations in each variant of the experiment and a comparative analysis and evaluation of the effectiveness of the methods used was carried out. Results. It is shown that the combination of step-by-step sporophyte-gametophyte selections under the action of high-temperature regimes (43°C and 45°C), at early stages (F1-F3) lead to more stable, productive offspring in F5-F7 both for sporophyte and gametophyte traits, compared to using only gametophyte selections and stronger differences relative to the control variant. The gradual alternation of selections at different stages of ontogenesis also leads to the production of offspring with a shorter period of passage of the phenophases "seedling-flowering" - "flowering-maturation" and a stable manifestation of signs that determine the quality of the fruits. Using only gametophytic selections and traditional methods of selection was less effective than alternating sporophyte-gametophyte ones. Conclusions. The differentiating ability of the selection methods used and their influence on obtaining more resistance and productive genotypes was established. The advantage of the method of step-by-step alternation of sporophyte-gametophyte selections, which led to the production of new lines (118/1, 124/1, 133-11/1, 133-12/1, 134/1, 110/1 and 7/1) with high resistance at different stages of ontogenesis (sporophyte-gametophyte), shorter vegetation period and high fruit-forming capacity in three different years of research (2015-2017).