Plant Genome IV Conference Plant Genome IV Conference
The level of genetic diversity of three American wild rice populations recently collected in prospection trips was investigated. Two of the populations were collected in the Amazon River Basin (ARB1 and ARB2) and one in the Paraguay River Basin (PRB1). The populations were tentatively described as Oryza glumaepatula following morphological evaluation. Isozymes systems (IDH, EST, SDH, MDH, PGM) and RAPD markers obtained with twenty random decamer primers were used to evaluate forty-eight individuals randomly chosen from each population. Twenty isozyme and 229 RAPD bands were used as phenotypes in the analysis. Isozymes were also used to genotype the individuals and to estimate allelic frequencies and heterozigozity values. The results indicate that the within population variability is smaller than the between population variability. ARB1 and ARB2 were more similar to each other than to PRB1. Heterozigosity values and the average number of alleles per locus of ARB1 and ARB2 were 0.0/1.25 and 0.01/2.0, respectively, while the values for PRB1 were 0.358/2.75. Genetic diversity values varied highly (ARB1= 0.143 to 1.00; ARB2= 0.588 to 1.00 and PRB1= 0.429 to 1.00). Multivariate analysis suggested that PRB1 could be a different species and cytological analysis confirmed the hypothesis. Diploid and tetraploid specific markers were identified.