Maize leaf plays an important role in the synthesis of organic compounds. It hosts the interception of light energy and conversion to organic energy, and the capture and assimilation of carbon dioxide in order to produce food. In this study, we explore the heritability of the maize leaf length, leaf width, and the number of leaves of two maize genotypes, JNE and BLC. The estimates of heritability varied from 0.2 to 0.44. Only estimates for leaf width and leaf length are significant. The coefficients of genotypic correlation were between 0.45 and 0.66, and like the estimates of heritability, only the genotypic correlations between parents and offspring are significant for leaf length and leaf width of the two genotypes. The estimates of degree of genetic determination also known as heritability in the broad sense are all high. They range between 0.52 and 0.85. We determined a significance criterion for the degree of genetic determination, the critical value at the level of significance = 0.05. We evaluated three methods for finding the critical value. With two methods based on the algebraic transformation of a function of the Snedecor's F and a simulation based on that function of F, it can be concluded that the estimates of the degree of genetic determination of leaf width of both the JNE and BLC genotypes are significant. With the third method that is based on fitting a Beta distribution, the critical value helped to conclude that none of the estimates of the degree of genetic determination is significant. The Pearson coefficients of correlation between plant height and all three leaf traits showed significant correlation between them, except leaf length and number of leaves.