Answer:
The value of X₁, which is how tall the new generation of corn will grow equals 5.6 feet.
Explanation:
Before answering the question, we need to know a few concepts.
Artificial selection is the selecting practice of a specific group of organisms in a population -that carry the traits of interest- to be the parents of the following generations.
Parental individuals carrying phenotypic values of interest are selected from the whole population. These parents interbreed, and a new generation is produced.
The selection differential, SD, is the difference between the mean value of the trait in the population (X₀) and the mean value of the parents, (Xₙ). So,
SD = X₀ - Xₙ
Heritability in the strict sense, h², is the genetic component measure to which additive genetic variance contributes. The heritability might be used to determine how the population will respond to the selection done, R.
h² = R/SD
The response to selection (R) refers to the metric value gained from the cross between the selected parents. R can be calculated by multiplying the heritability h², with the selection differential, SD.
R = h²SD
R also equals the difference between the new generation phenotypic value (X₁) and the original population phenotypic value (X₀),
R = X₀ - X₁
-------------------------------------------------------------------------------------------------------------
Now that we know these concepts and how to calculate them, we can solve the proposed problem.
Available data:
According to what we sow previously, we need to find out the value of X₁, which reflects how tall the new generation of corn will grow.
X₁ = R + X₀
We already know that X₀ = 4 feet,
Now we need to calculate R.
We know that h² = 0.8,
Now we need to calculate SD
Xₙ = 6 → Parentals media height
X₀ = 4 → Population media Height
SD = X₀ - Xₙ
SD = 4 - 6
SD = -2 feet.
Knowing this, we can calculate R
R = h²SD
- h² = 0.8
- SD = 2
R = 0.8 x 2
R = 1.6
Finally, once we know the R-value we can calculate the X₁ value
X₁ = R + X₀
X₁ = 4 + 1.6
X₁ = 5.6
