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

`"1600 g"`

Explanation:

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 xx "600 g" = "400 g" + "1200 g" = "1600 g"`.

Let me know if you didn't understand this properly.
P.S. I also gave this test yesterday!