Let W n be a wheel graph with n spokes. How does the genus change if adding a degree-3 vertex v, which is not in V (W n ), to the graph W n ? In this paper, through the joint-tree model we obtain that the genus of W n +v equals 0 if the three neighbors of v are in the same face boundary of P(W n ); otherwise, γ(W n +v) = 1, where P(W n ) is the unique planar embedding of W n . In addition, via the independent set, we provide a lower bound on the maximum genus of graphs, which may be better than both the result of D. Li & Y. Liu and the result of Z. Ouyang etc. in Europ. J. Combinatorics. Furthermore, we obtain a relation between the independence number and the maximum genus of graphs, and provide an algorithm to obtain the lower bound on the number of the distinct maximum genus embedding of the complete graph K m , which, in some sense, improves the result of Y. Caro and S. Stahl respectively.