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This article in CS

  1. Vol. 16 No. 2, p. 256-259
    Received: June 26, 1975

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Stability and Performance of Hard Red Spring Wheat Bulks for Grain Yield1

  1. R. H. Busch,
  2. J. Hammond and
  3. R. C. Frohberg2



Twenty-eight hybrid populations resulting from crosses among eight high-yielding parents of hard red spring wheat (Triticum aestivum L. em Thell.) were evaluated as F1's in one environment, as F2 bulks in six environments, and as F3 bulks in five environments. The average yields of the F2 and F3 bulks were similar to midparent performance across environments. Neither the F2 nor the F3 bulk generations exhibited superior yield performance in stress environments when compared to their midparents. Performance of the bulks varied from 95.9 to 110.9% of midparent across environments. The yield rank of each generation bulk was generally consistent from F2 to F3 (r=0.87, significant at the 0.01 probability level) since the same seven crosses (top 25%) would have been chosen with either generation yield test. The F2 bulk yields also were associated with midparent yields (r=0.73, 0.01 level) and F1 yields (r=0.73, 0.01 level). Parents were included in each trial, however, the Fa bulks were tested together with F2 bulks in only two of the environments. The F2 bulk yields, averaged over environments, correlated as well with the F1 yields as with midparent.

Regression analyses of response to environments for yield indicated that bulks had the same range of b values as parents. Average deviations from regression were smaller for bulks than for parents, but the deviations did not differ significantly. Parental deviations from regression for yield were correlated with gca (general combining ability) effects of their progeny (r=0.72, 0.05 level), but gca effects for response (b) were not significantly associated (r=0.49). Deviations from regression apparently were inherited from the parents in a relatively more predictable manner than response (b) to environments.

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