Estimation of Genetic Parameters for Resistance to Erwinia Soft rot, Specific Gravity, and Calcium Concentration in Diploid Potatoes

Tubers of clones from a diploid Solarium phureja Juz. & Buk.-S. stenotomum Juz. & Buk. hybrid population were evaluated for Erwinia resistance, specific gravity, Ca concentration, size, shape, eye depth, skin color, and overall appearance. Clones from four different steps in a selection process for high specific gravity were used. The first step consisted of clones with no selection for high specific gravity, and the fourth step consisted of the most advanced clones in the selection process for high specific gravity. Half-sib families of these clones were grown, and tubers were evaluated for the same traits as the parent clones (except for Ca concentration). Parent clones and half-sib families of Step 2 were planted on two different dates. Heritability estimates were determined for Ca concentration, tuber size, tuber shape, eye depth, skin color, and overall tuber appearance. Broad- and narrowsense heritability were estimated for each selection step and date separately. Estimates for broad-sense heritability were high for all traits except for tuber shape. Narrow-sense heritability (averaged across five estimates) was highest for skin color (0.51) and eye depth (0.52). The average narrow-sense heritability estimates were moderate to low for tuber appearance (0.27) and near zero for tuber size and shape (& 0.03 and 0.06, respectively). Results indicate that genetic improvement of the population should be possible for skin color, eye depth, and tuber appearance. The low to moderate estimates of narrow-sense heritability suggest that family selection is needed for improvement. The low to moderate genotypic correlation coefficients between traits indicate that simultaneous selection for Erwinia resistance, specific gravity, Ca content, and overall tuber appearance is feasible.