Flower position stem length and seed shape were three charac

Flower position, stem length, and seed shape were three characters that Mendel studied. Each is controlled by an independently assorting gene and has dominant and recessive expression as follows:

Character   Dominant Recessive

Flower Position Axial (A) Terminal (a)

Stem Length Tall (T) Dwarf (t)

Seed Shape Round (R) Wrinkled (r)

If a plant that is heterozygous for all three characteristics is allowed to self-fertilize, what proportion of the offspring would you expect to be as follows?

a. homozygous for the three dominant traits

b. homozygous for the three recessive traits

c. heterozygous for all three characters

d. homozygous for axial and tall, heterozygous for seed shape

Solution

Explanation :-Trihybrid cross would result in the heterozygous F1 (AaTtRr) self fertilization would result in 64 progeny (F2) generation. Thus punnrt square would be of 64 boxes and gametes are as follows-----ATR, ATr, AtR, Atr, aTR, aTr, atR, atr.

Part a:-Homozygous for three dominant traits 1/64.

AATTRR (ONE PROGENY OUT OF 64)

Part b:- Homozygous for three recessive traits 1/64 aattrr (one out of 64 progeny)

Part c:-Heterozygous for all three characters 8/64 (AaTtRr)

Part d;- Homozygous for axial and tall heterozygous for seed shape 1/64 (AATTRr)