Inheritance of petal colour and its independent segregation from seed colour in Brassica rapa

The inheritance of petal (flower) colour and seed colour in Brassica rapa was investigated using two creamy-white flowered. yellow-seeded yellow sarson tan ecotype from Indian subcontinent) lines, two yellow flowered, partially yellow-seeded Canadian cultivars and one yellow-flowered, brown-seeded rapid cycling accession, and their F-1, F-2, F-3 and backcross populations. A joint segregation of these two characters was examined in the Fz population. Petal colour was found to be under monogenic control, where the yellow petal colour gene is dominant over the creamy-white petal colour gene. The seed colour was found to be under digenic control and the yellow seed colour (due to a transparent coat) genes of yellow sarson are recessive to the brown partially yellow seed colour gents of the Canadian B. rapa cvs. 'Candle' and 'Tobin'. The gents governing the petal colour and seed colour are inherited independently. A distorted segregation for petal colour aas found in the backcross populations of yellow sarson x F-1 crosses, but not in the reciprocal backcrosses, i.e. F-1 x yellow sarson. The possible reason is discussed in the light of genetic diversity of the parental genotypes.