The amount of information about multiple phenotypic effects of the selection for single root traits is yet limited in carrot. Thus, the objectives of the present work were: (1) verify the possibility of using the direct effects of the path analysis to estimate correlated gains; (2) identify the best strategy to obtain correlated gains for root mass; (3) determine which root tissue would allow the highest gains aiming to increase the root diameter; and, (4) verify the possibility of having gains for root color in conjunction with other evaluated traits. Tree carrot populations (derived from the cv. Brasília) were cultivated during the summer in Brasília, Federal District, Brazil. Twenty-five roots were harvested (90 days after sowing) in each plot and the root mass, root length, root diameter, diameter of root xylem; phloem width, and the chromaticity values a* of the xylem and phloem were evaluated individually. Analysis of variance was carried out with information from within and among populations. The genetic correlations among this set of traits were also calculated. Path analysis was carried out and the correlated response (based upon the genetic correlation) was estimated. The direct effects of the path analysis and the direct gains from selection were also determined. The replacement of the genetic correlations with the direct effects of the path analysis was found to be the best procedure to estimate the single trait selection effect on the other traits after removing the indirect effects. Selection for larger root mass did not show correlated gains for the other evaluated traits. Selection for larger root diameter would result in the largest correlated gain for root phloem thickness. The selection for highest a* value of the xylem would result in a decrease in the xylem diameter. However, the direct selection for highest a* value and larger xylem diameter could result in positive gains to both traits.
Dauucs carota; breeding; correlated response
