engleski

Assessment of physicochemical traits and molecular diversity in Portuguese maize germplasm: A basis for selection of genotypes in breeding for improved maize bread quality

Through several centuries of natural and human selection, a very diverse maize germplasm has been developed in Portugal conquering an important role in animal feed and especially in human food (bread). The traditional maize leavened bread called 'broa' is still consumed in the country and highly praised in some regions. The growing number of people intolerant to gluten (celiac disease) justifies an increased interest in maize as a bread flour source alternative. For these reasons, the technological ability for bread production is among the traits valued by our maize germplasm characterization. From a molecular study of 54 Portuguese maize inbred lines we selected 19 lines as representatives of the Portuguese maize diversity. The chosen lines were characterized further with additional microsatellite markers, distributed throughout the maize genome, and evaluated for bread making quality which included eight physicochemical traits (protein, fat, fibre and amylase content, viscosity profiles and flour colour). A total of 136 alleles were detected, with an average allele number of 5.04 per locus. Polymorphism information content (PIC) values and observed pairwise genetic distances revealed the existence of large variability among inbreds. All the inbreds could be unambiguously distinguished from each other but cluster analysis showed no clear groupings of the inbreds. On the other hand, by principal component analysis based on the eight physicochemical traits, the inbred lines were classified into four distinct quality groups. The correlation between the molecular and the bread quality traits distance matrices was not significant and the AMOVA analysis suggested that no genotypic differentiation existed among the bread quality groups. These findings support the joint use of molecular and physicochemical traits in characterization, evaluation and management of maize germplasm collections, to serve as the basis for selecting lines in bread quality breeding programs.

Zea mays; microsatellites; plant genetic resources; inbred lines; quality breeding

nije evidentirano