Carrot cultivars of the Brasília group have good adaptation to cultivation in summer conditions in Brazil. However, there is the need for selection to increase the germination potential at high temperature in order to reduce seed costs and to obtain more uniform stands, mainly in hot areas of the country. The objective of this work was to define the best strategy to maximize gains in quality of carrot seeds using half-sib families derived from a population of the cultivar Brasília assessed for vigor and germination at 20 and 35ºC. Seeds of 70 half-sib families of carrot were evaluated using a randomized block design with 4 replicates of 50 seeds for each family. Data were examined by analysis of variance, and the parameters heritability and correlation between the traits and the direct genetic gains by selection and by selection indexes were estimated. It was found that vigor and germination were efficient to distinguish the families evaluated at the temperatures 20 and 35ºC. The evaluated selection indexes showed identical performance at the two temperatures, thus, selection can be performed by using any of the indexes. The temperature at 35ºC provided higher gain than at 20ºC.
Daucus carota L.; thermo-inhibition; plantlet establishment