Non-Parametric Stability Analysis of Tuber Yield in Potato (Solanum tuberosum L.) Genotypes

In order to study tuber yield stability of 15 potato genotypes, this research was carried out using randomized complete block design with three replications in three different research stations in Iran during two growing seasons. The combined analysis of variance indicated that the main effects of genotype (G), environment (E) and their interactions genotype and environmen (G×E) were highly significant (p < 0.01). The principal component analysis (PCA) based on rank correlation matrix indicated that the first two PCAs explained 86.7% of the variance of original variables. Based on bi-plot analysis, the stability parameters were classified into four groups. Clustering of the genotypes according to the mean yield and nonparametric stability statistics showed that there were two main clusters. Overall, according to mean rank of nonparametric stability parameters, G1, G15, G5, G6, G12 and G13 had the lowest variations and were recognized as the most stable genotypes. Genotypes G9, G11, G14, G3 and G7 had the highest values of mean rank of parameters and therefore, would be considered to be the most unstable. According to the present study, the stability measures Ysi, R, TOP and LOW were associated with mean yield (MY) and the dynamic concept of stability. Therefore, these procedures were suitable for selecting stable and high yielding genotypes. Based on these parameters, genotypes G5 (45.57 t/ha) and G1 (39.99 t/ha) were identified as high yield stable genotypes.