Genetic Resources and Crop Evolution 48: 347–352, 2001. 347  2001 Kluwer Academic Publishers. Printed in the Netherlands. Evaluation of genetic relationships among botanical varieties of cultivated peanut ( Arachis hypogaea L.) using AFLP markers * Guohao He and Channapatna Prakash Center for Plant Biotechnology Research College of Agricultural, Environmental and Natural Sciences * Tuskegee University, Tuskegee, AL 36088, USA; Author for correspondence (e-mail: hguohao@tusk.edu; phone: 334 727 8459; fax: 334 727 8552) Received 15 November 1999; accepted in revised form 22 March 2000 Key words: AFLP markers, Botanical varieties, Cultivated peanut, Genetic diversity, Polymorphism Abstract Forty-four accessions of cultivated peanut (Arachis hypogaea L.) representing six botanical varieties of two subspecies along with three accessions of the wild relative A. monticola Krapov et Rigoni were evaluated for their genetic relationships using the AFLP marker technology. Fifteen AFLP primer pairs ( EcoRI/ MseI) generated 28 distinct polymorphic markers that were employed to develop unique profiles of all accessions and to construct a phenogram. The results showed that the botanical varieties aequatoriana and peruviana were closer to subspecies hypogaea than subspecies fastigiata Waldr. to which they belong, and the wild A. monticola was not distinct from the cultivated A. hypogaea. Although the extent of genetic diversity in peanut is low compared to many other crops, our studies show that by employing the AFLP approach, sufficient DNA variation can be detected in the cultivated peanut germplasm to conduct evolutionary studies. Introduction Similarly, isozyme markers could detect no differ- ences within either subspecies of A. hypogaea, and The cultivated peanut or groundnut (Arachis hypo- the two subspecies varied only by a very few such gaea L.) is an important legume used for its oil and markers (Grieshammer and Wynne 1990; Lu and protein content. It consists of two subspecies, hypo- Pickersgill 1993; Lacks and Stalker 1993). The RFLP gaea and fastigiata Waldr., which are further classi- and RAPD techniques have detected very little poly- fied into six botanical varieties based on their mor- morphism among accessions of cultivated peanut phology and growth habits (Krapovickas and Gregory (Kochert et al. 1991; Lanham et al. 1994; Halward et 1994). Botanical varieties ‘hypogaea’ and ‘hirsuta’ al. 1992; Paik-Ro et al. 1992; Garcia et al. 1995), and belong to ssp. hypogaea while varieties ‘fastigiata’, thus could not be employed in genetic studies of ‘peruviana’, ‘aequatoriana’ and ‘vulgaris’ belong to peanut varieties. We have, however, recently shown ssp. fastigiata (Table 1). that AFLP technique (Vos et al. 1995) detects DNA DNA-based markers provide a reliable means of polymorphism in the cultivated peanut (He and Prak- estimating the genetic relationships between geno- ash 1997). types and taxonomic groups as compared to mor- For continued improvement of the cultivated phological markers (Gepts 1993). However, molecu- peanut through breeding, an understanding of genetic lar markers have not aided studies on genetic relation- diversity helps in determining the extent of variation ships in cultivated peanut because of the limited in the germplasm. Precise understanding of the degree detectable polymorphism using protein and DNA of genetic relationships between genotypes and markers in this crop. Singh et al. (1991, 1994) found botanical varieties of peanut may provide insights into very limited or no variation among the accessions of the domestication and evolution of this crop. Further, the cultivated peanut using seed protein profiles. it would have immediate tangible impact on peanut