Quantitative genetics 1

Different wheat families were grown in the same field and their phenotypic, genetic and environmental variances were measured. Genetic variance was estimated as the variation between families, environmental variance was estimated as the residual variance. The results for different traits are shown in the table. Calculate the genetic variance for plant height, rounded to 1 or 2 numbers after the decimal dot

(HInt "Quantitative genetics 6 - Applications" 02:12)

(a)  

Different wheat families were grown in the same field and their phenotypic, genetic and environmental variances were measured. Genetic variance was estimated as the variation between families, environmental variance was estimated as the residual variance. The results for different traits are shown in the table. Calculate the heritability for Flag Leaf Area rounded to 1 or 2 digits after the decimal dot.

(HInt "Quantitative genetics 3 - Broad sense heritability" 00:30)

(a)  

Different wheat families were grown in the same field and their phenotypic, genetic and environmental variances were measured. Genetic variance was estimated as the variation between families, environmental variance was estimated as the residual variance. The results for different traits are shown in the table. Are the estimated heritabilities:

(Hint "Quantitative genetics 3 - Broad sense heritability" 00:30)

• Broad sense

• Narrow sense

Different wheat families were grown in the same field and their phenotypic, genetic and environmental variances were measured. Genetic variance was estimated as the variation between families, environmental variance was estimated as the residual variance. The results for different traits are shown in the table. Are the estimated heritabilities:

(Hint "Quantitative genetics 3 - Broad sense heritability" 02:18)

• High

• Low

• Impossible to tell without a reference value

For the same experimental design, narrow sense heritabilities were also estimated (last column in the table). How do you explain the difference in values between broad sense and narrow sense heritability?

(Hint "Quantitative genetics 4 - Additive and non additive effects" 00:10)

• Heritability can change between two measurements

• The environment of the experiment must have changed between the two measurements

• H² includes non-additive genetic effects, whereas h² does not

What does it mean when a trait has a narrow-sense heritability of 0.62?

• 62% of the trait in an individual is determined by the effects of genes

• On average, about 62% of variation in the population can be explained by the genetic relatedness among individuals.

• If we take two individuals in the population, 62% of the differences among them will be genetic