The characterization and assessment of genetic diversity among maize (Zea mays L.) hybrids that are widely grown in France: Chromatographic data and isozymic data

Summary Zein chromatographic and isozyme electrophoretic data were used to characterize 61 hybrids of maize (Zea mays L.) that are of current widespread usage in France. A similar study was also carried out for 88 hybrids that are widely available in the central corn belt of the U.S. Objectives were to 1) investigate the degree to which isozyme and chromatographic data could provide unique hybrid identification; 2) to evaluate the wealth of genetic diversity available among hybrids that are currently cultivated in France and in the U.S.; and 3) to compare the patterns and extent of genetic diversity found in both countries with respect to their registration, breeding, and seed production practices.Isozyme data showed that all French hybrids were unique germplasm. However, numerous hybrids had chromatographic profiles that were identical for 11 major peaks and these hybrids could thus have some common germplasm at least among their female parental lines. Although there was a broad base of isozymic diversity among French hybrids, the amount in cultivation was less since the few most widely used hybrids, which were planted on approximately half the cultivated area, were similar for their isozymic and zein chromatographic profiles. Approximately only 50% of the U.S. hybrids were shown to be unique with the remainder classified into groups; at least some of the hybrids within each group could be genetically identical products. Leading U.S. hybrids were unique germplasm but numerous hybrids that collectively covered a large acreage appeared to encompass a relatively narrow genetic base.For the continued success of agriculture, it will be important to improve breeding, registration, and marketing practices in order to ensure the continued supply of genetically different and improved elite hybrids.