STUDY OF MAIZE GENOTYPES RICH IN ANTHOCYANINS FOR HUMAN AND ANIMAL NUTRITION

Anthocyanins are very important nutraceuticals not only because they protect plants against biotic and abiotic stresses (Winkel-Shirley, 2002) and they seem to be involved in plant yield (Frascaroli and Landi, 1998), but also because they exert antioxidant abilities able to protect human and animal health (Virgili and Marino, 2008). Maize is able to accumulate anthocyanin in different tissues (Escribano-Bailon et al., 2004; de Pascual-Teresa et al., 2002), so that it can be considered a functional food. On this basis the general aim of this PhD project was to develop maize genotypes with the usual commercial and nutritional value and at the same time able to accumulate anthocyanins in kernels, so to confer the new colored varieties a surplus value compared to the uncolored traditional ones. In maize different allele combinations of the anthocyanin regulatory genes are able to color different tissues, in different extent. From the evaluation of these different genotypes some interesting results came to light: while the r1 gene seemed to be involved in maize yield, the B/Pl genotypes were able to reach the highest anthocyanin amounts in kernels. Therefore they were used to generate the lines characterized in this PhD thesis (popcorn, polenta and sweet corn). To develop uniform individuals, the parameters affecting the anthocyanin final amount in kernels had been studied: the seed weight, the pericarp thickness, the environment and the expression level of the regulatory genes. Among all, a primary role of the epigenetic phenomena emerged; this fact can complicate the breeding work because it force to select the most colored individuals generation by generation, so surely this aspect must be examined more in depth. In the meanwhile a recurrent breeding scheme was used to develop pop corn, polenta and sugary corn colored with anthocyanin: a commercial yellow line was crossed with the colored variety carrying the B/Pl alleles for the anthocyanin biosynthesis. using the Marker Assisted Selection (M.A.S) to help the selection. The anthocyanin final amount in the kernels of the new developed colored lines has been considered as competitive compared to the usual anthocyanin sources, even if the cooking processing affected – but not wiped off- the pigment content and the antioxidant ability. However the anthocyanin presence seemed not to affect the appreciability degree tested on a blinded group of subjects, so that the new color products could be ready for the market. This kind of work and analyses are very interesting in regard the fact that two Near Isogenic Lines (NIL), differing for the synthesis of only one class of metabolites, are under comparison. This fact can simplify the study of the advantage given by the presence of the anthocyanins in foods; moreover these isogenic foods can also be used to analyze the relationship between the presence of the pigments in foods and the human and animal health and consequently to confer a property to a specific single class of molecules, simplifying the analyses and the reading of results.