Question

A tetra-hybrid plant produces fruits of 1 kg while minimum weight is 400 g. What will be the maximum weight of a fruit ? (1) 600 g (2) 1600 g (3) 1200 g (4) 1800 g

Answer 1

This is a question of Polygenic inheritance. When all the alleles are recessive, we get minimum weight condition and when all the alleles are dominant, we get maximum weight condition.

In a tetrahybrid condition

(

AaBbCcDd

)

, the weight of the plant is

1000 g

, i.e minimum weight

+

weight due to four dominant alleles.

Therefore, the weight of four dominant alleles

=

1000 g

−

400 g

=

600 g

.

Now, the weight due to

8

dominant alleles

=

minimum weight

+

2

×

600 g

=

400 g

+

1200 g

=

1600 g