Corncobs are often used for showing innende patterns. All the grains on a cob have the same
female parent, and with careful pollination they
can also have the same male parent. A variety
with coloured and starchy grains was crossed
with a variety with white and waxy grains. The F,
grains were all coloured and starchy. The F, plants
grown from these grains were crossed (F, F,).
1 Calculate the expected ratio of F, plants,
assuming that the genes for coloured/white
and starchy/waxy grains are unlinked. Use
a genetic diagram to show how you reached
your answer.
[3]
2 The actual frequencies were:
1,774
coloured starchy
coloured waxy
263