Response of tomato varieties and F2 reciprocal hybrids to stress temperatures

Abstract

The paper presents the results of assessing the resistance of some cultivars and 2 reciprocal F2 hybrid combinations: Desteptarea x Flacara/Flacara x Desteptarea and Flacara x Vrojainii/Vrojainii x Flacara of tomato to stressful temperatures (41º, 43ºC). Seedlings grown at 25ºC served as a control variant. The analysis of the variability of the resistance character was carried out based on the length of the embryonic radicle, the stem, the whole seedling. In most cases, stress temperatures produced significant inhibition of growth organs. Through cluster analysis (k-means method) in the variant 41oC, the reciprocal combinations F2 Desteptarea x Flacara / F2 Flacara x Desteptarea were identified, and in the case of the 43oC temperature – Exclusiv, Prestij, Desteptarea, Flacara and F2 Desteptarea x Flacara that formed separate clusters, with the highest values of the evaluated characters, which provides opportunities for their use in breeding programs as reliable sources of resistance. The research of the influence of stressful temperatures on the distribution of plants in phenotypic classes demonstrated that obtaining a greater number of segregates with reduced sensitivity to high temperatures is more likely in the case of the combinations F2 Desteptarea x Flacara and F2 Vrojainii x Flacara.