Stability and Broad-Sense Heritability of Mineral Content in Potato: Potassium and Phosphorus

Abstract

In the study of nutritional variability in potato it is desirable to know the present range of expression and genetic potential for increase. Potato breeding lines and varieties in two separate trials were evaluated for potassium and phosphorus content by wet ashing and Inductively Coupled Argon Plasma Emission Spectrophotometer analysis. Stability and broad-sense heritability were determined. Among genotypes, potassium content ranged from 1.85 and 2.49 % DW while phosphorus content ranged from 0.16 to 0.34 % DW over both trials. Genotype by environment interactions were significant in the Tri-State and Western Regional Red/Specialty (WR-R/SP) trials for both potassium and phosphorus, while environments were not. Genotype was a significant source of variation for both minerals in the WR-R/SP trial only. In the Tri-State trials, 7 and 4 of ten clones were unstable before and after removal of environmental heterogeneity, respectively, for potassium content, and 5 and 4 genotypes were unstable before and after removal of environmental heterogeneity, respectively, for phosphorus. In the WR-R/SP Trials, 7 and 3 of 13 clones were unstable before and after removal of environmental heterogeneity, respectively, for potassium content, and 3 and 4 genotypes were unstable before and after removal of environmental heterogeneity, respectively, for phosphorus. Broad sense heritability was low for both potassium and phosphorus in the Tri-State Russet-Skin Trials but high for both potassium and phosphorus in the WR-R/SP Trials. Although potato is a minor contributor of phosphorus to the human diet, it is an important source of potassium. Adult males and females receive 12 % of the Recommended Dietary Allowance of potassium from 100 g of potato. Estimates of broad-sense heritability from these two trials suggest that genotypes with higher levels of both potassium and phosphorus can be selected from within the Red/Specialty market class, but not from within the Tri-State russet class. An increase in potassium content in the potato, for which the daily need in the human body is so high, could be a boon to human health.