Genetic and Morphological Diversity among Traditional Ethiopian Highland Maize
Effective plant breeding and crop improvement programs depend on the availability of crop genetic diversity. In the search for diverse breeding materials, landraces are usually die major source of variation. In the highland areas of Ethiopia, maize contributes greatly to household food security. However, maize cultivars that are used in the highland regions are well adapted, but low yielding open-pollinated varieties that have resulted from centuries of planting and selection. These accessions may be grouped into a smaller number of reproductively isolated populations, which may each have accumulated specific genetic adaptations for different highland conditions. To capture the genetic variability, 287 maize accessions were collected throughout the highland regions of Ethiopia. Our field studies (Beyene et al, 2005a) revealed that highland maize accessions of Ethiopia are highly variable for morphological and agronomic characteristics. However, morphological variation does not always reflect the real genetic variation because of genotype-environment interaction. In this project bulked Amplified Fragment Length Polymorphism (AFLP) and Simple Sequence Repeat (SSR) markers were employed to classify the highland maize accessions into distinct groups, and to test the utility of bulking DNA (by bulking leaf samples) for large-scale genetic characterization of open-pollinated varieties. In the bulked-AFLP experiment, eight EcoR Ⅰ/Mse Ⅰ primer combinations were used. Of a total of 650 AFLP markers that were scored, 89.5％ were polymorphic. Pair-wise genetic dissimilarity estimates revealed dissimilarity coefficients ranging from 0.32 to 0.69, with a mean of 0.57. Cluster analysis grouped most accessions collected from the Northern highlands into one major cluster while the Western and Southern accessions clustered together. This rinding was published in a recent paper (Beyene et al, 2005b). In the SSR experiment 20 SSR loci were used. The average number of alleles per locus was 4.9 and the average polymorphism information content was 0.61. Pair-wise genetic dissimilarity coefficients ranged from 0.27 to 0.63 with a mean of 0.49. Ward minimum variance cluster analysis grouped most of the accessions from the Northern agroecology into three major clusters and all of the Southern and Western accessions into another cluster suggesting that genetic differentiation was low amongst the Western and Southern accessions. Overall, the bulked-AFLP and SSR marker analyses highlight the use of bulked Leaf samples for large-scale genetic characterization of open-pollinated varieties, which are commonly cultivated in developing countries. The study also indicated that the existence of ample genetic diversity in highland maize accessions, which can be exploited by hybridization and selection.
AFLP Ethiopia Genetic resources Genotypic diversity Maize SSR
Y.Beyene A.A.Myburg A.M.Oberholster
Department of Genetics & Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0002, South Africa
国际会议
The 2nd International Conference of Plant Molecular Breeding（第二届植物分子育种国际会议）
海南三亚
英文
90
2007-03-23（万方平台首次上网日期，不代表论文的发表时间）