Nascimento, Wellington F.
Rodrigues, Jucelene F.
Veasey, Elizabeth A.
Total Authors: 5
 Univ Sao Paulo, Luiz de Queiroz Coll Agr, Dept Genet, BR-13400970 Sao Paulo - Brazil
 Univ Fed Sao Paulo, Dept Biol Sci, BR-09972270 Sao Paulo - Brazil
 Univ Calif Davis, Dept Plant Sci MS1, Sect Crop & Ecosyst Sci, Davis, CA 95616 - USA
Total Affiliations: 3
Genetic Resources and Crop Evolution;
Web of Science Citations:
Dioscorea trifida L. (Dioscoreaceae) is among the economically most important cultivated Amerindian yam species, whose origin and domestication are still unresolved issues. In order to estimate the genetic diversity maintained by traditional farmers in Brazil, 53 accessions of D. trifida from 11 municipalities in the states of Sao Paulo, Santa Catarina, Mato Grosso and Amazonas were characterized on the basis of eight Simple Sequence Repeats (SSR) and 16 Inter Simple Sequence Repeats (ISSR) markers. The level of polymorphism among the accessions was high, 95 % for SSR and 75.8 % for ISSR. The SSR marker showed higher discrimination power among accessions compared to ISSR, with D parameter values of 0.79 and 0.44, respectively. Although SSR and ISSR markers led to dendrograms with different topologies, both separated the accessions into three main groups: I-Ubatuba-SP; II-Iguape-SP and Santa Catarina; and III-Mato Grosso. The accessions from Amazonas State were classified in group II with SSR and in a separate group with ISSR. Bayesian and principal coordinate analyzes conducted with both molecular markers corroborated the classification into three main groups. Higher variation was found within groups in the AMOVA analysis for both markers (66.5 and 60.6 % for ISSR and SSR, respectively), and higher Shannon diversity index was found for group II with SSR. Significant but low correlations were found between genetic and geographic distances (r = 0.08; p = 0.0007 for SSR and r = 0.16; p = 0.0002 for ISSR). Therefore, results from both markers showed a slight spatially structured genetic diversity in D. trifida accessions maintained by small traditional farmers in Brazil. (AU)