A Comparison of Soft Red Winter Wheat F2 Populations, Their F1 Hybrids, and Parents

The cost of F₁ hybrid soft red winter wheat (Triticum aestivum L.) seed developed with chemical hybridizing agents is from two to three times that of conventionally bred cultivars. Unlike pureline cultivars, it is not possible to save seed from a hybrid wheat crop to produce an identical crop the next year. Costly F₁ hybrid seed has led to speculation about using F₂ seed for subsequent crop production. The objective of this research was to evaluate this production alternative by comparing F₁ hybrids with their respective F₂ populations and parents for a number of agronomic traits. Three families (each consisting of an F₁, a derived F₂, and the original parents) were grown in four environments in Maryland during 1986 and 1987. Treatments were planted in a randomized complete block design in a split-plot arrangement of treatments with families as whole plots and generations as split plots. A significant 8.3% yield decline was found for the F₂ populations compared with the F₁ hybrids averaged over the environments and families. However, seven of the 12 family-environment combinations had no significant differences for yield between the F₁ and F₂ populations. High parent heterosis of 4.5% for yield was observed for the hybrids averaged over all families and environments. Only four of 12 family-environment combinations were found to have significant high-parent heterosis. Although significant differences among family members existed for other agronomic traits studied (i.e., spike emergence date, tiller length and variability, test weight, harvest moisture content, and milling and baking quality), none of these differences was judged undesirable for the production of an F₂ population. It is concluded that an F₂ population, derived from an F₁ hybrid wheat, could be successfully used by a farmer for crop production given current hybrid seed costs and market prices. Success is dependent upon the hybrid from which the F₂ population is derived and the environment in which it is grown. Furthermore, the low levels of high-parent heterosis suggested that pureline cultivars probably would provide the most economical results for a farmer at the present time.