Evaluation of Seed Yield Stability of Sunflower Genotypes Using Non-Parametric Statistics

Evaluating of sunflower genotypes under different environmental conditions would be useful to identify genotypes with high stability and yield potential. In order to study yield stability of sunflower genotypes, 11 new hybrids along with four cultivars (namely Golsa, Ghasem, Shams and Farrokh) were evaluated in a randomized complete block design with four replications under four experimental field stations across Iran including Karaj, Sari, Kermanshah and Dezful during 2018-2020. The results of combined analysis of variance indicated that the effects of environments, genotypes and genotype × environment interaction were significant for seed yield. Existence of genotype × environment interaction, suggested that genotypes responded differently to the studied environment conditions. Therefore, there is the possibility of stability analysis. Cluster analysis based on the nonparametric stability statistics grouped genotypes in to three main clusters. According to the mean rank of all studied nonparametric stability parameters, the genotypes No. 5 and 14 with the lowest value of mean rank were distinguished as stable genotypes, meanwhile genotypes No. 1, 11, 12 and 9 with the highest values of mean rank were identified as non-stable genotypes. Also, the results indicated that the nonparametric statistics Si, NPi and NPi were associated with mean seed yield and the dynamic concept of stability. Therefore, these methods would be suitable for selecting stable and high yielding genotypes in sunflower. Finally, the genotype No. 5 with mean seed yield of 3355 kg ha-1 and high broad stability was distinguished as superior hybrid which can be used in the future breeding programs for producing the new cultivar with high yield and stability potential.