Dissimilarity among families and correlated selection response for root characters of carrots grown in two agroecologic production systems in Distrito Federal

Abstract

The objective of this work was to calculate the dissimilarity among families and the correlated selection response in a carrot population grown in two agroecologic production systems. The experiments were conducted in Brasília, in the summer of 2006/2007. A hundred half-sib families of carrot were evaluated in a complete randomized block design with two replications. Twenty plants were harvested individually per plot and were evaluated for root characters. Joint and separated variance analyses for the two systems were performed. The dissimilarity among and between families and the correlated selection response were calculated. It was mainly verified that inside of the population, in both production systems, it is possible to select for more dissimilar families to be used in a next recurrent selection cycle, providing gains with heterosis. In selecting among or within families, for larger root mass, gains superior to 2% per selection cycle could be expected, for longer roots and with larger xylem diameter. Selection for higher levels of carotenoids, mainly in the xylem cannot be made separately from the yield components, length, measures of diameter and average root weight.