Determination of the stability of grain protein production by triticale among nine environments within the southeastern United States

Twenty-four varieties of hexaploid triticale (Triticosecale Wittmack) were grown in nine environments among five states in the southeastern U.S.A. Seed samples were assayed for percent protein and milligrams protein per hundred seed. Each environment was assigned an index equal to the average of the protein values for all varieties grown in that environment. Each variety was regressed linearly on environmental indices, so as to evaluate stability of seed protein characters over environments. The fit to linear regression was evaluated. Estimates of broad sense heritability for percent protein and milligrams protein per hundred seed were found to be 1% and 11% respectively. Coefficients of variation were 10.1 for percent protein and 12.1 for milligrams protein per hundred seed. Correlation between seed size and milligrams protein per hundred seed was found to be 0.67; correlation between seed size and percent protein was found to be -0.58. Correlation between percent protein and milligrams protein per hundred seed was 0.18. The correlation between environmental stability (regression coefficients) and protein value was found to be non-significant for both percent protein and milligrams protein per hundred seed. The coefficient of variation was not found to have a significant association with the regression coefficient; therefore, the coefficient of varia tion should not be used as an indicator of environmental stability. Although protein levels varied among environments, the rankings of individual varieties remained relatively constant among iii iv environments. The results obtained from this study would not pre clude the development of a breeding program to enhance protein levels in triticale even though heritability estimates were relatively low.