Questions -

Q1. Multiplicative gene action can be a consequence of dominance or epistatic interaction of genes.  Dominant gene action and epistatic gene action are defined as: (matching - selection from choices)

the incremental effects of gene dosage

the interaction of genes with the environment

the interaction of genes at different loci

the interaction of alternate genes at a locus

Q2. Broad sense heritability is one of the measures that breeders will use to evaluate whether the variation that they observe in a quantitative trait is influenced by genetics. Which of the following are true of heritability?

a. Is a measure of the proportion of an individual's phenotype that is heritable.

b. Is a fixed characteristic of a trait.

c. Theoretically, heritability will change with each generation of selection.

d. Heritability is an estimate of the number of genes involved in a trait.

Q3. Considering traits that are controlled by the additive action of a large number of genes, which of the following are true:

a. The F1 phenotype will generally be intermediate between the two parents.

b. Assuming the parents of the cross were homozygous, the F1 phenotype will be uniform.

c. The F1 phenotype will always be more affected by growing environment than the parents.

d. A & B are true

e. A & C are true

f. B & C are true

g. A, B, & C are true

h. None of the above are true

Q4. Considering traits that are controlled by the additive action of a large number of genes--  

The F2 population will be more variable than the F1 and generally will have a mean more similar to the higher value parent.

True

False

Q5. Considering grain protein concentration in wheat:

assume that the traits that is controlled by the additive action of genes at 6 loci, and assume that you have grown the F2 in a perfectly uniform environment and assume can measure grain protein concentration precisely and assume all genes have the same effect size (these are BIG assumptions)-

Into how many grades of grain protein concentration phenotypic classes would you expect to be able to partition the F2 population?

a. 6

b. 12

c. 13

d. 15

e. 30

Q6. Considering oil concentration in soybean:

assume that the traits that is controlled by the additive action of genes at 3 loci (parents differ at 3 loci).

assume that you have grown the F2 in a perfectly uniform environment

assume can measure oil concentration precisely and

assume all genes have the same effect size (these are BIG assumptions)-

What percentage of the population will be in the central (mean) concentration class?

a. 1.56

b. 9.4

c. 23.4

d. 31.25

e. 50

Q7. Dr. Baenziger's graduate student reports that the broad sense heritability for kernel weight in her recombinant inbred mapping population was 0.63.

We can safely conclude that the narrow-sense heritability of kernel weight is at least 0.63.

True

False

Q8. Which of the following strategies are used by plant breeders to improve heritability in their testing programs:

a. Use best management practices to remove nutrient deficiencies

b. Use supplemental irrigation to mitigate the effects of drought and soil variation

c. Adjust plant populations and row spacing to optimize production

d. Use experimental designs to help account for environmental variation

e. Incorporate well-characterized check varieties into trials

f. All of the above

Q9. Thinking about the partitioning of genetic variance into its components, identify the three primary components of heritable variation:

Epistatic

Dominance

Additive

(matching - select from choices below)

Variance associated with alleles interacting at one locus

Variance of average effects of substituting one allele for another

Variance associated with the response of the plant to the environment

Variance associated with the interaction of alleles at different loci