Use of low doses of cobalt-60 gamma radiation on carrot seeds and their effects on plant growth and yield

Seeds of the cultivars Nantes Forto (European origin) and Brasilia (Rio Grande do Sul origin) carrot (Daucus carota L. var. sativus (Hoffm.) Thell), were irradiated with 0.0 (control); 2.5; 5.0; 7.5 and 10.0 Gy at a dose rate of 11.5 Gy/h for each dose, and sowed in the same day and six days after irradiation. 'Brasilia', for all treatments produced more root weight than the control. The 2.5 Gy dose treatment produced about 11.9% more than the control when the sowing was in the same day of irradiation. When the sowing was six days of irradiation, the 2.5 Gy dose and 10.0 Gy dose treatments, produced respectively 6.0% and 1.6% more than the control, while the others were less than the control. At the 2.5 Gy dose the 'Nantes Forto' produced 8.6% and 6.5% for treatment 5.0 Gy respectively for the first and second sowings. The doses treatments did not alter any commercial root standard.