F₁ Hybrids Versus Random F₅ Line Performance and Estimates of Genetic Effects in Spring Wheat¹

Abstract

Three hard red spring wheat ( Triticum aestivum L.) crosses which had exhibited significant heterosis in a previous study were analyzed genetically by Hayman's generation mean analysis. Approximately 90 random F 3 ‐ derived F 5 lines were used as an agronomic comparison with the F 1 hybrid generation and to determine if the genetic analysis based on parental, F 1 , F 2 , F 3 , F 4 , and backcross selfed generation means were of use in determining the possible results of selection. Results of the genetic analysis indicated that selection of individual plants should be effective for plant height and heading date. Less value was realized from the analysis of the three crosses for yield. F 5 lines which performed significantly better than the F 1 hybrid were found in each cross. One F 1 hybrid failed to exceed the yield of its high parent, but both of the other hybrids were heterotic. F 0 lines, derived from the best‐yielding F 5 lines, and their respective parental F 5 lines performed similarly when grown in the same experiments.