Stability analysis for grain yield of black cumin (Nigella sativa L.) genotypes in Bale, South-East Ethiopia

Yield data of 12 black cumin ( Nigella sativa L.) cultivars tested across 9 rain-fed environments during the 2013-2015 growing season using RCBD in 3 replications. The AMMI analysis tested in nine environments (years) were showed that the yield was significantly affected (P<0.001) by genotypes and environment main effects. But non significant for GxE interaction. The model revealed that differences between the environments accounted for about 90% of the treatment sum of squares. The genotypes and the GxE interaction also accounted significantly for 4% and 6% respectively of the treatment SS. The first principal component axis (PCA 1) of the interaction captured 51.32% of the interaction sum of squares. Similarly, the second principal component axis (PCA2) explained a further 18.20% of the GEI sum of squares. The mean squares for the PCA 1 and PCA 2 were significant at P=0.01 and cumulatively contributed to 69.52% of the GxE interaction SS, leaving 30.37% of the variation in the GxE interaction in the residual. The AMMI and AMMI stability value (ASV) identified G10 as the most stable and high yielding genotype.