Homeostatic Relationships of Single- and Double-crosses of Corn

The inherent homeostatic properties of single- and double- cross corn hybrids were studied by growing the plant materials in six locations over three years. Measurements of plant height and ear weight were recorded and used to calculate means and variances. Variances were pooled over locations and years and confidence intervals for the variance estimates were computed by use of the chi-square method. A lower variance for an entry, when compared with other entries grown in the same environment, was considered to be the result of relatively better homeostatic properties. Comparisons of entries were made by the use of confidence intervals for the variance estimates, with overlapping of intervals for the variance estimates, with overlapping of intervals indicative of no significant difference in variability. The theory that single-cross hybrids are more variable between locations and double-cross hybrids more variable within locations was partially substantiated. It was concluded that more diverse environmental conditions, either more locations and/or more years, would be required to more accurately detect differences in the relative homeostatic properties of the entries used