Levels of hybrid vigor for earliness, height, three components of yield, and grain yield were examined in the F 1 and F 2 generations of a diallel cross of seven varieties selected from hard red, soft white, and soft red winter wheats. Entries planted in hills showed little interaction with seeding rates of 3 to 15 plants per 930 cm 2 (1 ft 2 ), but the degree of hybrid vigor tended to be greater for hill seeding than for normal seeding.
