We compute the partition functions of N=1 gauge theories on ${S}^2$ × $\mathbb{R}_ε^2$ using supersymmetric localization. The path integral reduces to a sum over vortices at the poles of ${S}^2$ and at the origin of $\mathbb{R}_ε^2$. The exact partition functions allow us to test Seiberg duality beyond the supersymmetric index. We propose the N=1 partition functions on the Ω-background, and show that the Nekrasov partition functions can be recovered from these building blocks.