Genetic Diversity of Maize Inbred Lines Revealed by SSR Markers and Their Relationship with Performance of F1 Hybrids

摘要

A SSR marker system (including 52 primers from AMBIONET) was used in 2003～2004 for determination of genetic diversity among 72 inbred lines, including 51 lines from National Maize Research Institute of Vietnam, 1 line from USA and 20 inbred lines from CIMMYT. Genetic distance was determined using Jaccard's similarity coefficient and final dendrogram was construction using UPGMA method. Cluster analysis divided the samples into 12 groups. Several key inbred lines in each group were selected for test cross. Among 32 cross combinations, 4 combinations in-group 11,1 in group 1 and 1 in group 10 were found to be in the same group. The genetic distance was correlated with F1 hybrids yield under field conditions. Differentiation among inbred lines, between paired inbred lines, and heterotic groups were genetically distinct because there was high polymorphism among genotypes. Some hybrid combinations made from the same heterotic group could still produce high yield. However, dendrogram analysis indicate that they are in the sub-groups, which are rather far away from each other (value of GD is 0.67～0.69). In contrast, the high yield in cross combination (more than 8 tons/ha) was resulted from the higher value of GD (0.6～0.8). Therefore, in order to obtain higher frequency of crosses with higher yield, breeders should pay attention to pedigree, genetic distance and heterotic group. SSR markers could help in eliminating those materials that are genetically similar in order to reduce the workload in the field.