Adaptability and stability parameters for immature seeds and pods and mature dried seeds in cowpea genotypes in Brazil northeast

The aim of this study was to estimate adaptability and stability parameters in genotypes of cowpea for the yield of immature seeds and pods and mature dried seeds, in order to enable the recommendation of cultivars for the region of São Francisco Submedium valley. We evaluated 30 cowpea genotypes, being fourteen lines of Embrapa Semiarid, six commercial cultivars and 10 landraces in the municipalities of Juazeiro-BA and Petrolina-PE. The experiments were conducted in the second semester, during the years 2013, 2014 and 2015. For adaptability and stability analysis, the methodologies of Eberhart and Russell, Lin and Binns were used, in addition to the multiplicative method, based on principal components analysis (AMMI). A significant difference was observed for the mean squares of treatments in all environments, as well as the pooled ANOVA (P<0.01) for the effects of genotypes (G), environments (E) and G*E interaction. The lines P290, P303, P508 and PC950409D02E showed yield of immature seeds exceeding 2140 kg ha-1, broad stability and good predictability in the series of evaluated environments, and has great potential to be recommended as new cultivars for the region of São Francisco Submedium Valley.201