The inheritance of onion bulb color was studied utilizing white bulbs resistant to Colletotrichum gloeosporioides that segregated from the population 'Roxa do Barreiro' and two inbred Unes with yellow bulbs originated from 'Super Precoce" and 'Pira Ouro' cultivars. The white bulbs and the inbred Unes were crossed to obtain the F1 and F2 generations (yellow x white). Both F1 generations were of red bulbs and in the F2 generation there were segregations to red, white and yellow bulbs in a proportion of 9:4:3, respectively. It was concluded that the inheritance of bulb color in these crosses is controlled by two contrasting genes hi the parental (ii cc RR = white bulbs, ii CC rr = yellow bulbs) material). It is probably possible to obtain a new variety or inbred line resistant to C. gloeosporioides with yellow bulbs or white bulbs, which, when crossed with a yellow line, will result in a yeUow bulb F1 resistant to this pathogen.
onion (Allium cepa); bulb color; Colletotrichum gloeosporioides