8. Where a female male-sterile component and a male component which does not restore male fertility are used for the production of CS seed of a hybrid variety of maize, the seed shall be produced—
(a)by blending seed lots in a proportion appropriate to the variety where, on the one hand a female male-sterile component has been used and, on the other, a female male-fertile component has been used, or
(b)by growing the female male-sterile component and the female male-fertile component in a proportion appropriate to the variety.