Introgression from modern hybrid varieties into landrace populations of maize (Zea mays ssp. mays L.) in central Italy

Landraces are domesticated local plant varieties that did not experienced a deliberate and intensive selection during a formal breeding programme. In Europe, maize landraces are still cultivated, particularly in marginal areas where traditional farming is often practised. Here, we have studied the evolution of flint maize landraces from central Italy over 50 years of on-farm cultivation, when dent hybrid varieties were introduced and their use was widespread. We have compared an 'old' collection, obtained during the 1950s, before the introduction of hybrids, and a recent collection of maize landraces. For comparison, a sample of maize landraces from north Italy, and of improved germplasm, including hybrids and inbred lines were also used. A total of 296 genotypes were analysed using 21 microsatellites. Our results show that the maize landraces collected in the last 5-10 years have evolved directly from the flint landrace gene pool cultivated in central Italy before the introduction of m...