Morpho-physiological Characteristics and Molecular Markers of Maize Crosses Under Multi-location Evaluation

The superior lines A1, A2, B1 and B2, which were developed from honeycomb evaluation in two different environments (A and B), were crossed in the field in environment A to obtain the following six crosses A1×A2, A1×B1, A1×B2, A2×B1, A2×B2 and B1×B2. Measurements performed in a RCB design included quantitative and quality characteristics and molecular data based on ISSR molecular markers. The objective of this study was to investigate the presence of variation of quantitative, quality and molecular characteristics among crosses of superior selected lines that developed after multi-location selection. Principal component and cluster analyses were used for grouping genotypes, while correlations were performed to investigate relations between all quantitative and quality characteristics. According to PCA analysis, the six newly-developed crosses, which were evaluated in different environments, showed measurable distances between the identical lines (B1×B2 (A) and B1×B2 (B)) suggesting genotype-environment interaction. Also, cluster analysis showed that some crosses, such as A1×B2 (A) and A1×B2 (B), are grouped in separate and distinct clusters indicating that dissimilar developmental environments may cause changes in quantitative traits. This may be due to the origin of the selected lines, since they were developed in different locations. Lines developed in the same location gave crosses that had similar behavior in the two locations. Also, it is clear that a kind of gene fixation is apparent from the C3 cycle in A1xA2 cross, since it is close (and similar) to the C4 cross. Crosses including A2 line showed a greater stability in both environments.