RELATIONSHIP OF CLONAL MEAN TO THE UNIFORMITY AND STABILITY OF TUBER SPECIFIC-GRAVITY IN POTATOES

Regression analysis of plot mean and plot standard deviation for specific gravity of tubers from 190 unreplicated 12-hill breeding plots, was used to study the relationship of mean and within-plot uniformity. Using two data sets from the Western Regional Potato Variety Trial, regression analysis of clone mean for specific gravity within a location on overall location mean was used to study the relationship of mean and inter-location stability. A highly significant (p < 0.01) but very weak (r2 = 0.04) positive coefficient of determination existed between plot means and plot standard deviations. No relationship was found for mean specific gravity of clones and their stability across different environments. The results suggest that selection of high specific gravity combined with uniformity and/or stability is a feasible goal for breeding programs.