Question

Suppose farmers wanted to increase the mass of their tomatoes. The average weight of their tomatoes is 87 grams. To increase tomato mass, the farmers breed only tomatoes with an average weight of 100 grams. The standard deviation, s, in weight in the parent population is 8 grams, and the heritability for the trait is 0.65. Calculate the strength of selection on tomato mass.

1) -1.6
2) -0.35
3) -13
4) -1.04

Answer 1

The strength of selection on tomato mass is the difference between the mean weight of selected tomatoes and the mean weight of the population, which is 13 grams (option 3).

Step-by-step explanation:

The question asks us to calculate the strength of selection on tomato mass. In quantitative genetics, the strength of selection (S) can be defined as the difference between the mean phenotype of the selected parents (in this case, the tomatoes being chosen for breeding) and the mean phenotype of the original population. The formula to calculate the strength of selection is:

S = mean of selected parents - mean of the population

Given that the average weight of the tomatoes selected for breeding is 100 grams and the average weight of the tomatoes in the original population is 87 grams, we apply this formula:

S = 100 grams - 87 grams = 13 grams

Therefore, the strength of selection on tomato mass is 13 grams, which corresponds to option 3).