Productivity and tolerance to the leaf blight disease of hybrid and open-pollinated carrot cultivars

The replacement of open-pollinated carrot cultivars by hybrids is a reality in the seed market. We aimed to evaluate the productive potential of experimental carrot hybrids, tolerance to leaf blight as well as the uniformity of roots, compared to open-pollinated cultivars. Eighteen carrot genotypes, 15 experimental hybrids, one commercial hybrid (Juliana) and two open-pollinated cultivars (OPs) (Brasilia and BRS Planalto) were evaluated in the 2011/12 crop in Brasilia, Brazil, in randomized blocks design with three replications in plots of 2 m(2). At 90 days the incidence of leaf blight was evaluated and at 100 days we measured production component characters, in addition to taking at random 50 roots per plot for individual measures. Difference was observed for all traits among the genotypes, hybrid being better or worse than OPs. For total root yield, no contrast was found between hybrids and OPs. However, hybrids showed higher amount of marketable roots compared to OPs. Regarding uniformity of root lenght, OPs were similar to hybrids, but more irregular in relation to diameter and individual weight. The results demonstrate superiority of hybrids in relation to OPs for marketable production and uniformity of roots.