Question

Suppose a graduate student is studying a population of bluebonnets along a roadside. The plants in this population are genetically variable. She counts the seeds produced by 100 plants and measures the mean and variance of seed number. The variance is 20. Selecting one plant, the student takes cuttings from it and cultivates them, producing many genetically identical clones. She then transplants these clones into the roadside population, allows them to grow for one year, and then counts the number of seeds produced. The student finds that the variance in seed number among the cloned plants is 10. From the phenotypic variance (Vp) of the genetically variable and genetically identical plants, calculate the broad-sense heritability (H2) of seed number for the roadside population of bluebonnets. Number Choose which assumption must be made in order for this estimate of broad-sense heritability to be correct o The phenotypic variance of the genetically identical plants is the same as the genetically O o O variable population. The genetic variance component is strictly the result of additive genetic variance. The environmental variance of the genetically identical plants is the same as that of the genetically variable population. There is no phenotypic variance associated with the environment.

Answer 1

From the given data, Solution: Broad-sense heritability H2 = VG/Vp ------- the phenotypic variation Vp=VG+VE here Vp=20 (variance) 20 = VG+ VE ----------------Equation II in the identical population , VG=0 and here Vp=10 (cloned plants) 10 = 0+VE Ve=10 By substituting Ve value in Equation II we will get 20=VG + 10 (20-10=10) Vg= 10 Apply the values of VG and Ve of the roadside population in equation I H2 = 10/20 =0.5 Assumption : Correct answer: The environmental variance of the genetically identical plants is the same as that of the genetically variable population.