Exploitation of genetic resources for improving maize grain quality

The introduction of hybrids into cultivation brought up a significant increase in maize (Zea mays L.) grain yield, and a better resistance to pathogens. On the other hand, the possibility to help maintaining a good health through a convenient diet have recently focused the interest in food plants on the nutritional quality issue. A recent survey of maize germplasm from several countries revealed the existence of a wide genetic variability for the main components of the grain (Berardo et al., 2009). In particular, Italian germplasm was found to be rich in some bioactive compounds, e.g. carotenoids. With the aim to find new sources of alleles to improve the nutritional quality of maize hybrids, a set of old inbreds were grown in the field during two years and selfed. The chemical composition of the grain was investigated by NIR spectroscopy in terms of protein, oil, starch and carotenoids. A preliminary test of resistance to Fusarium verticilliodes ear rot was also carried out testing the inbreds under kernel artificial field inoculation. The severity of Fusarium attack, evaluated using ratings based on the percentage of kernels with visible symptoms of infection, showed in most of the inbreds a medium – low susceptibility; fumonisin accumulation was also determined. The use of hyperspectral imaging for distinguishing between inoculated, non-inoculated, open and self pollinated maize kernels was evaluated. Hyperspectral imaging is a powerful technique that could be used for cereal grains characterization in order to produce localized information. Because of its high speed of analysis, it could be of great value when thousands of samples need to be analyzed for resistance to fungine pathogens in a maize breeding program. Moreover, non-destructive analysis of single kernels composition could help identifying outlying individuals both for breeding and for industrial seed sorting applications, selecting and propagating single seeds with desirable composition traits. The genetic diversity among these genotypes is currently being described by molecular markers.