Prediction of progeny variation in oat from parental genetic relationships

Summary The ability to predict agronomic performance of progeny from a cross would be a great benefit to plant breeders in selecting parents. The predictive value of parental genetic relationships estimating F₁ progeny means and F₄ family variances of nine argronomic traits was tested in 76 oat crosses, using genetic distance measures based on coefficients-of-parentage, quantitatively inherited morphological characters, and discretely inherited biochemical and morphological characters. Coefficients-of-parentage were better predictors of F₁ performance than similarity measures derived from plant morphology or discretely inherited characters. Combined distance measures were better estimators of F₁ specific combining ability (SCA) effects than any single measure. Among cultivars of similar adaptation and quantitative morphology, crosses between parents with high coefficients-of-parentage gave higher SCA effect values than crosses of distantly related parents for grain yield and total biomass. The opposite was found for crosses among cultivars of different adaptation or quantitative morphology. The best predictor of trait variances among F₄ families was coefficients-of-parentage. Crosses between more distantly related parents produced larger variances among families than crosses between closely related parents for plant biomass. For grain yield, test weight, heading date, grain filling period, and maturity date, crosses between more closely related parents produced larger among-family variances than crosses of distantly related parents. Crosses between more distantly related parents involved at least one parent unadapted to central New York, and resulted in most of the progeny being generally unadapted. This, in part, may account for the low genetic variances for heading date, test weight, and grain yield in crosses of distantly related parents.