A total of 47 rice accessions collected from Kenya were investigated the genetic variations and classified into two cluster groups, A and B, by polymorphism data of 65 simple sequence repeat (SSR) markers. Clusters A and B corresponded to Japonica and Indica Groups, respectively. The number of Japonica Group accessions was limited in comparison with those of the Indica Group. Based on their patterns of reaction to standard differential blast isolates (SDBIs), these accessions and 57 control cultivars including differential varieties and several accessions harboring partial resistance genes were classified again into three cluster groups: Ia (high resistance), Ib (intermediate resistance) and II (susceptible). The rice accessions from Kenya were classified only into groups Ia and Ib. The accessions from Kenya were finally classified into three categories, A-Ia, B-Ia and BIb , based on the two classifications of polymorphism of SSR markers and resistance. The Indica Group accessions had wider genetic variation for blast resistance than did the Japonica Group accessions. The three leading cultivars (Basmati 217, Basmati 370 and ITA 310) categorized into Cluster group Ia were susceptible to some SDBIs from Kenya. The genetic variation for blast resistance in Kenya was demonstrated as the first report using SDBIs.

The micro total analysis system (µ-TAS) has received much attention.For example, capillary electrophoresis (CE) integrated on a microchip, called microchip CE, has been aggressively studied. Laser-induced fluorescence (LIF) has been most commonly used as the detection method in microchip CE. 1,2 However, LIF detection necessitates a laser light source or spectroscopes. On the other hand, chemiluminescence (CL) does not require any light source and spectroscopes. Consequently, this technique holds tremendous promise for µ-TAS.On the basis of know-how obtained through our research of an ordinary CE with a CL detector, [3][4][5][6] we successfully developed a microchip CE with a CL detector. 7,8 Transition-metal ions and dansyl amino acids were analyzed by means of microchip systems using luminol 7 and peroxyoxalate reagent, 8 respectively. The microchip featured the simplest construction in principle; only two main channels, four reservoirs, a crossshaped injector, and the absence of a mixing junction for the CL reaction. However, the design of the microchip seems to require some devices for measurements of an extremely weak CL in the microchip.On the other hand, Nishimoto et al. developed novel microchips with a silicon membrane which cut off any stray light in order to improve the sensitivity of the optical absorption detection on microchip CE. 9,10 Microchips having a silicon membrane at the bonding interface between the cover and bottom plates were successfully fabricated on synthesized quartz glass substrates using a hydrofluoric acid solution bonding method. In this work, we applied microchips having a silicon membrane to CE with a CL detector and examined the effect of the membrane on CL detection. Luminol reagent and a Co(II) sample solution were used. It was found that cutting off CL light with the silicon membrane introduced a decrease of base-line noise in CL detection. The obtained results provided a clue for thinking about the microchip design suitable for CL detection. ExperimentalThe same microchips as those used in a previous study, 7 except for interposing a silicon membrane (250 nm thickness) between the cover and bottom plates, 9,10 were fabricated at Technology Research Laboratory of Shimadzu Corporation. The bottom plate (1.0 mm thickness) had a sample load and separation microchannels of 20 µm deep and 50 µm wide, while the cover plate (0.5 mm thickness) had ca. 1 mm diameter holes to facilitate access to the microchannels and to serve as reservoirs (R1 -R4). Four silicone rubber tubes (i.d. 2.0 mm, length 5 mm) were attached to the cover plate to make reservoir volumes larger for the electrolyte solution. 7,8 A schematic layout of the microchip is shown in Fig. 1. Although the three types of microchips used (Types 1 -3) had the same constructions of microchannels and reservoirs, they had a difference in the silicon membrane interposed between the glass plates (cover and bottom). Type 1 had no silicon membrane (it was the same microchip as used in a previous paper 7 ); Type 2 had a silicon me...

No abstract

No abstract

No abstract