Various soil disinfectants were analyzed on their ability to decrease the density of the bacterial wilt pathogen, Ralstonia solanacearum. For chemical fumigants such as chloropicrin and dazomet, R. solanacearum was sterilized up to 40 cm below ground,but no effect was observed at 60 cm below ground. Soil reduction using rice bran was also not able to sufficiently reduce the population of R. solanacearum in deep soil.On the other hand, soil reduction using molasses or ethanol led to high suppression of the R. solanacearum population up to 60 cm underground. Chlopic flow,a method of irrigation using chloropicrin, achieved a bactericidal effect against R. solanacearum up to 60 cm depth, even at low temperatures. However, disinfecting depth, even at low temperatures. However, disinfecting effect was negatively correlated with depth. The choice effect was negatively correlated with depth. The choice of disinfection method should be based on the degree of contamination in the soil, cultivation time, and economic costs.
(Bull.NARO.Agric.Res.Cent. No.7 (2019) in Japanese)
The identification of cultivars is important for the protection of intellectual property rights of breeders, for the maintenance of crop prices for farmers, and for precise product information for consumers. In Japan, several PCR methods have been developed for crop discrimination. To distinguish rice cultivars in particular, several types of DNA markers have been used. Multiplex PCR methods were developed previously using STS markers to reduce labor, time, and cost. Although SNPs are the most abundant polymorphisms among cultivars, SNP marker sets for multiplex PCR have not been created for rice discrimination. The present study's results demonstrate that the agarose gel electrophoresis of multiplex PCR with SNP markers was as reliable as STS markers, and 114 Japanese rice cultivars including the 10 most produced cultivars in Japan in 2014 and other major cultivars from each Japanese prefecture were successfully discriminated using 15 SNP markers, six STS markers and one SSR marker.
(Bull.NARO.Agric.Res.Cent. No.7 (2019)in Japanese)
