Grain yield adaptability and stability of blackeyed cowpea genotypes under rainfed agriculture in Brazil

The present study aimed to evaluate the grain yield adaptability and stability of 20 blackeyed cowpea genotypes under rainfed agriculture in North, Northeastern and Central/Western Brazil. Three parametric methodologies and one non-parametric methodology were used. We found significant differences among genotypes, environments, and interaction between genotypes and environments. The traditional method indicated that the MNC05-832B-230-2-3 line was the most stable but had low grain yield. The linear regression indicated that the California Blackeye-3 and California Blackeye-5 cultivars had wide adaptability and stability. The bi-segmented regression model indicated that the MNC04-783B-7-3 and California Blackeye-3 genotypes exhibited adaptation to favorable and unfavorable environmental conditions, respectively. The non-parametric method characterized the MNC04-783B-7-3 line as the most suitable and stable genotype. Spearman´s rank correlation showed that some methodologies should not be used simultaneously and that others should be used complementary to each other.