Estimating heritability of families derived from single plants at an advanced generation of self-fertilizing species: Developing general formulas and estimating spring wheat traits

Genetic expectations of total genetic variance, and between-family and within-family variance components were developed for any given generation (F_n) derived from single selfed plants of an earlier generation (F_k). A formula to estimate the heritability (h²) in any desired generation (F_n) was developed on the basis of these expectations. This formula estimates the value of the genetic variance from the phenotypic variance adjusted to the F₂ generation. Heritability estimates of culm length, heading date, and mean grain weight from two populations of F₆ families, each derived from a single F₅ plant, were computed using this formula, and a formula which estimates the value of the genetic variance from the phenotypic variance in the F_n generation (“F _n estimates”). The F _n h² estimates at F₆ were always higher than those adjusted to F₂ variance, due to the increase in additive variance and the reduction in dominance variance.