Evaluation of maize germplasm based on zein polymorphism from the archipelago of madeira

Zein polypeptides are a group of proteins that accumulate in maize endosperm during seed development, representing more than 60% of the total endosperm proteins in the mature seeds. To evaluate genotype variability of Madeiran maize germplasm, a biochemical study was conducted based on the prolamins of maize, zeins, extracted from endosperm meal of 43 populations of Zea mays L. maintained in the Germplasm hank of Madeira University along with the inbreed W64A, which was used as a polymorphic zein polypeptide standard profile. The zein polymorphism of these 44 maize populations were compared using two different electrophoresis techniques, SDS-PAGE in 15% discontinuous polyacrylamide gel and Acid-PAGE in 10% continuous polyacrylamide gel. SDS-PAGE allowed up to 16 polypeptides to lie identified with apparent molecular mass ranging from 28-kDa to 10-kDa. Acid-PAGE allowed up to 20 zein fractions to be identified. The data was submitted to principal component analysis (PCA) and canonical discriminant and similarity analysis. The SDS-PAGE zein polymorphism allowed us to detect 6 groups, assembling all maize populations and explaining 55.32% of all variability. The similarity analysis of zein patterns obtained by Acid-PAGE showed that among regional maize germplasm, 22.5 % of all populations seemed to be related and have a common ancestor. The ISOP71 seems to he the population closer to the common ancestor and appears related with the remaining maize populations, excluding tlie ISOP125. These results and the importance of zein polymorphism in the evaluation of maize germplasm from Madeiran Archipelago are discussed.