In Nicotiana, two inbred strains produce long (PL) and short (PS) corollas. These lines are crossed to produce F₁, and the F₁ are crossed to produce F₂ plants in which corolla length and variance are measured. The following table summarizes mean and variance of corolla length in each generation. Calculate H² for corolla length in Nicotiana. Generation Mean Corolla Length (mm) Variance PL 85.75 4.21 PS 43.15 2.89 F₁ 62.26 3.62 F₂ 67.37 38.10

Key Concepts

Heritability (H²)

Heritability (H²) is a measure used in genetics to quantify the proportion of phenotypic variance in a trait that can be attributed to genetic variance among individuals in a population. It is calculated using the formula H² = Vg / Vp, where Vg is the genetic variance and Vp is the total phenotypic variance. Understanding heritability is crucial for predicting how traits may respond to selection and for understanding the genetic basis of traits.

Phenotypic Variance (Vp)

Phenotypic variance (Vp) refers to the total variance observed in a trait within a population, which includes both genetic variance (Vg) and environmental variance (Ve). It is essential to distinguish between these components to understand how much of the observed variation is due to genetic differences versus environmental influences. In the context of the question, calculating Vp involves analyzing the variances from the different generations of Nicotiana.

Genetic Variance (Vg)

Genetic variance (Vg) is the portion of phenotypic variance that is attributable to genetic differences among individuals. It can be further divided into additive genetic variance, dominance variance, and interaction variance. In the context of the Nicotiana study, Vg can be estimated by comparing the variances of the parental lines and the F1 and F2 generations, which helps in understanding the inheritance patterns of corolla length.