Genotype-environment interactions of data for fifteen years from Tennessee small grain variety trials

The objectives of this study were to obtain estimates of the relative magnitudes of the various types of genotype X environment interactions on variety evaluation procedures, and to determine the correlations of yield among all locations.

Data from the University of Tennessee Agricultural Experiment Station performance trials from 1963 to 1977 were utilized for this research. Twenty-two varieties of winter wheat at eight locations, 15 varieties of winter barley and 11 varieties of winter oats at six locations were evaluated.

The genotype X environment interactions were all significant, except genotype X year interaction for oats. The magnitudes of their components were relatively small in relation to genotype components, except genotype X year interactions for wheat and barley. These results indicated that there was an important differential response to specific environmental conditions which was not accounted for by locations, but some differential varietal responses might be accounted for by years.

The correlations of variety performances for wheat and barley were significantly correlated among most of the locations. However those for oats were not significantly correlated among most of the locations. These results indicated that the varieties of wheat and barley were more generally adapted, whereas, varieties of oats were more restricted to certain locations.

Yield testing in environments which tended to result in similar rankings of variety performance could be reduced to a smaller number of environments. This could result in substantial savings to a breeding project for the expensive task of yield testing.