Similarities among a group of elite maize inbreds as measured by pedigree, F1 grain yield, grain yield, heterosis, and RFLPs.

Genetic distances were calculated among 37 inbred lines representing a wide range of related and unrelated elite Corn Belt germ plasm of maize (Zea Mays L.), using 257 probe restriction enzyme combinations. Genetic distances based on RFLP data were highly correlated with coefficients of parentage among pairs of lines. The RFLP-based distance had a higher correlation with single-cross grain yield performance and grain yield heterosis than any of the other measures of similarity we calculated using these same lines. The coefficients of determination (r (2)) from regressing the coefficient of parentage, grain yield, and grain yield heterosis on Nei's measure of genetic similarity based on RFLP data were 0.81, 0.87 and 0.77, respectively. A cluster diagram based upon the RFLP data grouped the lines into families consistent with the breeding history and heterotic response of these lines. We believe that measures of similarity calculated from RFLP data, coupled with pedigree knowledge and using molecular markers to locate quantitative trait loci (QTL), could allow maize breeders to predict combinations of lines that result in high-yielding, single-cross hybrids.