Diversity Assessment of Drought Tolerant Exotic and Adapted Maize (Zea mays L.) Inbred Lines with Microsatellite Markers

摘要

Knowledge about the genetic diversity within a germplasm allows for a more effective and efficient use of resources for crop improvement programs. Diversity assessment of 48 tropical drought-tolerant maize inbreds, 24 each from CIMMYT and IITA, was carried out with microsatellite markers to determine the genetic divergence between the two groups of maize inbred lines. Eighty-one polymorphic SSR markers were used for the assessment. Results showed that the average number of alleles per locus was 3.7.The mean polymorphic information content (PIC) was 0.51 whereas the average modified Roger's genetic distance (MRD) was 0.49. The mean genetic distance estimates between the CIMMYT and IITA lines were higher than the mean genetic distance among IITA lines or among CIMMYT lines. The average linkage cluster analysis separated the lines into two broad groups along institutional lines. The observed sub-groups within each main group were reflections of the relationships of the lines based on pedigree records. The Fst value of 19.5% reflects a high level of genetic differentiation between the two groups of lines. The results highlighted the presence of appreciable genetic divergence between CIMMYT and IITA lines that can be exploited for superior hybrid maize development.