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Upland rice (Oryza sativa L.) is precious genetic resource containing some valuable alleles not common in modern germplasm. In this study, genetic diversity and population structure of 98 upland rice varieties from northern part of Thailand were examined using nine simple sequence repeat markers. Number of alleles detected by the above primers was 50 with a minimum and maximum frequency of 2 to 10 alleles per locus, respectively. The polymorphic information content (PIC) values ranged from 0.375 to 0.714 with an average of 0.605 for the primers RM164 and RM1, respectively. Dendrogram cluster analysis of the SSR data distinctly classified all genotypes into three major groups (I, II and III), which corresponded to their places of collection. Population structure divided these genotypes into two distinct subpopulations. Subpopulation 1 consisted of upland rice varieties that collected from Chiang Rai province while the majority of subpopulation 2 were collected from Phayao and Phitsanulok provinces. Analysis of molecular variance revealed 68% variance among two subpopulations and 32% variance within subpopulations, suggesting a high genetic differentiation between the two subpopulations. The huge genetic variability of upland rice in northern part of Thailand can be used to complement the gene pool of modern genotypes in rice breeding program.

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Ochratoxin A (OTA) is a polyketide mycotoxin that is produced by Aspergillus and Penicillium. Food contaminated with OTA poses health risks and is a food-safety challenge. Quantitative polymerase chain reaction (qPCR) has been used to identify non-toxigenic and toxigenic strains from coffee samples using polyketide synthase (pks), the OTA synthesis gene. In this research, Aspergillus carbonarius (ochratoxin-producing strain) and A. flavus (non-ochratoxin-producing strain) were used to amplify a 141 bp fragment of the pks gene. The 141 bp PCR product was successfully cloned into TOPO ® TA plasmid. Subsequently, ten-fold dilutions of plasmid DNA were used to generate the standard curve by plotting the threshold cycle against log DNA concentration using qPCR. Further, fungal DNA contamination was quantified in 11 samples of roasted coffee using qPCR. All 11 coffee samples were accepted as safe, since the fungal genomic DNA contamination was less than 3.85 x 10 3 copies. Therefore, this research suggested that qPCR is a fast and accurate method to detect and quantify OTA-producing fungi in coffee products. Thus, we successfully developed a system to quantify fungal contamination in coffee.