In order to study patterns of inheritance, Neha had performed typical Mendelian experiments with pea plants in the field. In experiment one, she crossed a pea plant having white flowers (vv) with another pea plant bearing violet flowers (VV). In another experiment, in addition to the colour of the flower she also focussed on the height of the pea plant. This time she crossed a pea plant having violet flowers and tall height (VVTT) with another pea plant having white flowers and short height (vvtt).
What percentage is expected for the following traits as a result of these experiments? Give a reason.
A. Violet flowers in F1 and F2 generation in experiment one?
B. Tall height plants with white flowers in F2 generation in experiment two?
C. Percentage of medium height plants with light violet flowers in F1 and F2 generations in experiment two? Give a reason.
D. Percentage of short height plants with white flowers in F1 and F2 generations in experiment two?Â
Answers (1)
A. In experiment one, in F1 all plants (100%) will have violet (Vv) flowers and in F2, 75% (3/4) plants will have violet flowers (1/4 VV and 2/4Vv) because violet colour of the flower is a dominant trait in pea plant.
B. 3/16 or 18.75% pea plants will have tall height and white flowers (vvTT/vvTt)– a combination of a dominant and a recessive trait.
C. In pea plants, no half way characteristics are produced because even a single copy of T or V will produce the same result as two copies of T or V. Thus, no plants with medium height and light violet flowers will be
produced in F1 or F2 generation (zero percent).
D. In F1 generation all plants will have only dominant traits so no plant with short height and white flowers (recessive traits) will be produced (zero percent). In F2 generation 1/16 or 6.25 % plants will have short height with white flowers (vvtt) as both these traits are recessive.