Stability analysis of seed yield of Ethiopian caraway (Trachyspermum ammi L. Sprague ex Turrill) genotypes in multienvironment trials

Abstract

Twelve Ethiopian caraway genotypes were evaluated in eight environments in Ethiopia during 2014 and 2015 under rain fed condition. The field experiment was laid out using randomized complete block design with three replications. The objective of this experiment was to select high yielding and stable Ethiopian caraway genotypes with nonparametric methods. Combined analysis of variance was performed and 10 rank-based nonparametric stability parameters were measured. A pooled analysis variance for seed yield indicated that there were highly significant (P < 0.001) differences for main effects of genotype, environment, and their interaction. Genotype Gondar 027–2001 gave maximum number of umbel per plant. However genotype Gondar 010–2002 was recorded lowest number of umbel per plant. Adet 12–2000 gave highest plant height (64.7 cm) while Gondar 026–2000 gave lowest plant height (56.7 cm). A wide range variation was observed in days to flowering varied 87.7–91.8, days to maturity varied 157.16–159.8, plant height 56.7–64.7. The results of principal component analysis revealed that the stability statistics and yield were classified into three groups and related to two contrasting concept of stability. In this study, TOP and rank-sum were found to be useful measures for simultaneously selecting high yield and stable cultivars. These measures selected Gondar 027–2001 and Gondar 023–2000 that gave 2254.7 kg ha⁻¹ and 2186.1 kg ha⁻¹ seed yield, respectively, as stable and the National Variety Release Committee has released these genotypes as the first Ethiopian caraway varieties for production in 2017. Whereas, Adet 12–2000 and Gondar 018–2000 were the low yielding genotypes in some or all of the environments. Thus, Gondar 027–2001 and Gondar 023–2000 would be recommended for further demonstration and prescaling up in Amhara region and other similar agro ecologies.