Morphophysiological characterization of potato (Solanum tuberosum L.) genotypes prevailing in the core area of Punjab, Pakistan

Potato (Solanum tuberosum L.) is one of the most important vegetable crops and the fourth most important edible crop after the three major cereal crops. It is considered as an approximately complete diet food because of its nutritional value. Its center of origin is Peru, South America. In Punjab, Pakistan, the districts of Sahiwal and Okara serve as the core areas of potato cultivation. Thirty-three potato genotypes were collected from the core areas of Punjab for characterization. The genetic diversity of potato germplasm was assessed on the basis of morphophysiological traits. This experiment was conducted with a randomized complete block design and three replications. The data on 14 morphological and physiological traits were recorded. Analysis of variance indicated the presence of highly significant variation for each physiological and morphological trait. Correlation analysis showed that plant yield was highly correlated with the number of tubers per plant (0.484), tuber weight (0.648), and chlorophyll contents (0.365). By contrast, tuber dry matter exhibited a significant highly negative association with tuber moisture content (−0.753). Algorithmic hierarchical cluster analysis allocated the genotypes into four distinct clusters. Cluster 2, which was the largest cluster, comprised 18 genotypes. By contrast, cluster 4 was the smallest cluster and contained only two genotypes. The results of diversity analysis obtained through hierarchical clustering were further validated through principal component analysis (PCA). PCA provided five significant principal components that contributed 72.39% of the total variation. The principal components of the biplot explained 41.95% of the total variation, with tuber moisture content and tuber dry matter as distinct traits. Cultivars ‘SH-5’, ‘SH 7-18’, ‘Simply Red,’ and ‘Ruby’ were the vertex genotypes in the biplot. Results indicated the prevalence of significant variation in the tested germplasm. Furthermore, the assessment of diversity at the molecular level is recommended for the further validation of genetic diversity.