2023 Volume 25 Issue 1 Pages 24-30
Dietary fiber is a component with many physiological functions, but in recent years, the average dietary fiber intake of Japanese people has been below the target amount. From a fixed mutant group of ‘WPK’, which is a white panicle mutant of ‘Koshihikari’, treated with 0.1 M EMS (ethyl methane sulfonate), ‘WFE5’ was selected for its high dietary fiber content in the polished rice with a chalky appearance of brown rice. A cross was made between ‘WFE5’ and ‘Koshihikari’, and by backcrossing with ‘Koshihikari’ to the resulted F3 plant, ‘Koshihikari NIL [WFE5]’ was bred as a near-isogenic line of ‘Koshihikari’ for high dietary fiber. We evaluated the dietary fiber content, cultivation characteristics, and eating quality of ‘Koshihikari NIL [WFE5]’ for several years. As a result, ‘Koshihikari NIL [WFE5]’ was found to contain about three times as much dietary fiber as ‘Koshihikari’ in the polished rice, and its taste was determined to be comparable to that of ‘Nipponbare’. Therefore, Fukui Agricultural Experiment Station, Niigata University, and National Agriculture and Food Research Organization (NARO) jointly applied for the registration as ‘Shinfuku 1’ in the belief that the dietary fiber intake from the polished rice can contribute to improving the health of Japanese people. The dietary fiber content of ‘Shinfuku 1’ was 5.1 and 2.6% for the brown and polished rice, respectively, as a five-year average. The dietary fiber content varied from year to year, with larger grain weights tending to have a higher dietary fiber content. The cultivation characteristics of ‘Shinfuku 1’ were almost the same as those of ‘Koshihikari’, but its yield was 68% of ‘Koshihikari’. The brown rice of ‘Shinfuku 1’ was chalky and its thousand-grain weight about 15.5% less than that of ‘Koshihikari’, its resistance to lodging was slightly stronger than that of ‘Koshihikari’, and its pre-harvest sprouting was slightly easier than that of ‘Koshihikari’.
