Evaluation of Genetic Diversity of Soybean Introductions and North American Ancestors Using RAPD and SSR Markers
- G. L. Brown-Guedira *a,
- J. A. Thompsonb,
- R. L. Nelsonc and
- M. L. Warburtond
- a USDA-ARS, Plant Science and Entomology Research Unit, Dep. of Agronomy, 2001 Throckmorton Plant Science Center, Kansas State Univ., Manhattan, KS 66506 USA
b Pioneer Hi-Bred Intl., P.O. Box 328, Hamel, IL 62046 USA
c USDA-ARS, Plant Physiology and Genetics Research Unit, Dep. of Crop Sciences, 1101W. Peabody Dr., Univ. of Illinois, Urbana, IL 61801 USA
d CIMMYT Applied Biotechnology Center, Lisboa 27, Apdo Postal 6-641 06600 Mexico DF, Mexico
The genetic base of soybean [Glycine max (L.) Merr.] cultivars developed for North America is very narrow. This may threaten the ability of breeders to sustain improvement and increase vulnerability of the crop to pests. The objective of this research was to assess the relationship of 18 major ancestors of North American soybean germplasm with 87 plant introductions (PIs) that are potential new sources of genetic variation for soybean breeding programs. Genetic distances (GD) among the 105 genotypes analyzed were calculated from 109 polymorphic DNA fragments amplified with random oligonucleotide primers and simple sequence repeat (SSR) primer pairs. Two hierarchical clustering algorithms were combined with data resampling and multidimensional scaling (MDS) to evaluate relationships among the genotypes. Genetic distances ranged from 0.08 to 0.76, with a mean of 0.52. Genotypes were placed in 11 clusters on the basis of a consensus of the different methods utilized. Co-occurrence values calculated from the resampling iterations showed that the stability of clusters varied. The most stable grouping was among ancestors that corresponded with known relationships based on pedigree and maturity. Several groups of PIs are distinct from the majority of the ancestors. These genotypes may be useful to breeders wanting to utilize genetically diverse introductions in soybean improvement.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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