Four experiments were carried out with carrots genotypes during summer season in Distrito Federal, Brazil, to evaluate yield, bolting and leaf blight under organic and conventional conditions. The experiments were carried out in two locations and in each one two experiments were established, considering both crop systems. The experimental design was a random block with eight treatments and five replicates. The treatments consisted of the cvs. Alvorada, Brasília RL, Brasília Bionatur, Kuronan, Nantes 3 Tip Top, Carandaí AG 106, Brazlândia and Pop. 0212246. The soil was fertilized with organic compost for the organic trial and with chemical fertilizer for the conventional trial. Plants were evaluated for leaf blight incidence, 70 days after sowing date, through visual observation. Roots were harvested 95 days after sowing, washed, classified and weighted. Bolting was more frequent in Brasília Bionatur, under conventional condition, in Brazlândia. A difference of susceptibility to leaf blight among genotypes was observed in plants cultivated in the organic system. Nantes was the most susceptible while Pop. 0212246 was the most resistant. Alternaria dauci was observed more frequently at Brazlândia, while Cercospora carotae was observed at both locations, similarly, under organic conditions. For commercial and total yield, commercial and total root number, Pop. 0212246 and Brazlândia were the best materials in both crop systems. Total and commercial yield, total and commercial root number, number and weight of refused roots were higher in the conventional area, compared to the organic area. Brasília and Brazlândia can be recommended for Distrito Federal, independently of crop system, during summer season. Pop. 0212246 showed desirable agronomical characteristics and can be, in the future, available for farmers in Distrito Federal.
Daucus carota L.; Alternaria dauci; Cercospora carotae; disease resistance; commercial yield; crop systems
