Comparison of RFLP and morphological distances between maize Zea mays L. inbred lines. Consequences for germplasm protection purposes

A total of 145 maize inbred lines, representative of material released in France, were differentiated using RFLP markers and a set of discriminant morphological traits in order to evaluate the use of molecular markers for large-scale germplasm diversity analysis and determination of distinctness. Several criteria are proposed with respect to choice of probes, which should give reliable results for routine studies and have a known single-locus genetic determinism to avoid redundancy. A method is proposed by which to incorporate the data from different restriction enzymes obtained with the same probe. The precision of the estimation of the genetic distance is given. The relationship between molecular and morphological distances appears to be triangular, molecular divergence behaving as a limiting factor for morphological divergence. This suggested a scheme for incorporating molecular markers in studies of distinctness.