Heat tolerance is a major trait for tomato breeding programs targeted for lowland wet climates in equatorial and tropical areas of the world. High temperatures might cause several disturbances to morphological and physiological characteristics of the tomato flowers leading to yield constraints due to reduction in fruit setting. In the present work, an experiment was conducted to evaluate tomato breeding lines, derived from two tomato landrace populations cultivated by farmers in Roraima State (North Region of Brazil). Twelve inbred lines were obtained from these populations after one cycle of selection in a plastic house with high temperatures. These 12 inbred lines plus two standard cultivars ('Viradoro' and 'Santa Clara') were evaluated under temperature regimes ranging from 15ºC to 46.2ºC in Brasília. Significant differences were observed for the number of aborted fruits, number of ripened fruits per plant, mature fruit weight, soluble solids content, fruit firmness and color. The performance of the inbred lines (as a group) was, in general, superior to that of the standard cultivars for the number of aborted fruits, number of ripened fruits per plant, mature fruit weigh and fruit color. This genetic material could represent an important germplasm for breeding programs aiming to develop tomato cultivars with good adaptation to tropical and equatorial warm areas.
color; firmness; fruit setting; heat tolerance Lycopersicon esculentum; soluble solids
