Abstract:

The genetic diversity of three wild rice species in Hainan, China, was comparatively analyzed with 39 selected SSR markers which evenly distributed throughout rice genome and normally amplified bands in all three wild rice species. The results indicated that total 210 alleles were detected with 39 SSR primers. Polymorphic loci were 97.44% in Oryza rufipogon and 23.08% and 15.38% in meyeriana and O. officinalis respectively. Based on the related parameters, Oryza rufipogon showed the highest genetic diversity and O. officinalis maintained the lowest one. For instance, the percentage of polymorphic loci (P) and the mean number of alleles (A) per locus in O. officinalis were only 1/7 and 37% of those in O. rufipogon while those in O. meyerian were 2/7 and 39% of those in Oryza rufipogon respectively. Similarly, the average observed heterozygosity of O. rufipogon was the highest, which was 4.6 and 6.6 times of that of O. meyeriana and O. officinalis respectively. Wright’s F-statistics showed that the genetic variations within and among O. rufipogon populations were rather high, but those of both O. officinalis and O. meyeriana were very low, meaning that both individuals and populations of O. rufipogon have much different genetic backgrounds and those of the other two species have similar genetic backgrounds. The UPGMA clusters also showed that the three populations of O. rufipogon clustered into different groups at the point of I = 0.53, while the populations from the other two species grouped only after I = 0.9 or more. Similarly, the individuals within each population of O. rufipogon showed different genetic backgrounds with a few exceptions, but a lot of individuals in each population of both O. officinalis and O. meyeriana had the same genetic background. Considering above results, all tested populations of O. rufipogon and those with the highest genetic diversity of the other two species should be conserved with an in situ approach. O. meyeriana and O. officinalis should be conserved with only several individuals sampled in each population.

Key words: Oryza rufipogon Griff., O. meyeriana Baill., O. officinalis Wall., SSR, Genetic diversity