RELATIONSHIP BETWEEN GENETIC-MARKERS AND MORPHOLOGICAL TRAITS IN A MAIZE INBRED LINES COLLECTION

Genetic markers (isozymes), in addition to the traits recommended by t he UPOV convention, have been used in France since 1989 to characteriz e the maize inbred lines submitted to registration. In the years 1989, 1990 and 1991, a total of 974 inbreds has been described according to this procedure. Relationships between genetic markers were investigat ed and underlined the occurrence of linkage disequilibria within the t ested germplasm. These disequilibria appeared to depend strongly on th e breeding history of the germplasm. In some cases, these disequilibri a could be related to a major progenitor (foundation effect). Relation ships between genetic markers and quantitative traits were also pointe d out. High coefficients of determination (up to 60%) were in some cas es observed at the within group level, and also appeared to be very de pendent on the major progenitors of the group of interest. The consequ ences of these results for breeding and distinctiveness studies are di scussed.