In a plant, red fruit (R) is dominant over yellow fruit (r) and tallness (T) is dominant over shortness (t). I

Question

In a plant, red fruit (R) is dominant over yellow fruit (r) and tallness (T) is dominant over shortness (t). If a plant with RRTt genotype is crossed with a plant that is rrtt, what percentage of the offspring will be tall with red fruit?

Accepted Answer

To solve this dihybrid cross (), we analyze each gene independently :
1.  Fruit Colour (): Parent 1 produces only  gametes. Parent 2 produces only  gametes. All offspring will be  (Heterozygous Red). Probability of Red fruit = 100% (1).
2.  Height (): This is a typical test cross for height . Parent 1 produces  and  gametes (50% each). Parent 2 produces only  gametes. Offspring will be 50%  (Tall) and 50%  (Short).

Combined Probability: 
Probability (Red and Tall) = Probability (Red)  Probability (Tall) =  or 50%.

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