A new rice cultivar with giant embryo 'Haiminori'

"Haiminori", practical lowland rice cultivar with giant embryo was developed from a cross between EM40 and Akenohoshi. Crossing was carried out in 1984 at the rice breeding section of Chugoku National Agricultural Experiment Station. EM40 was mutant line with giant embryo selected from rice cultivar Kinmaze through the treatment of N-nitroso-N-methylurethane (NMU) in Kyushu University. The promising progeny line with giant embryo was named as Chugoku 137, and its adaptability and utilization had been examined since 1993. It was officially registered as Paddy Rice Norin 359 and named Haiminori by the Ministry of Agriculture, Forestry and Fishers (MAFF) in 1999. 1. Heading and maturing dates of Haiminori are 7 and 14 days later than those of Nipponbare, respectively. Its maturity is classified into medium-late maturity in the flatland along Seto inland sea. Its lengths of culm and panicle are 4 cm and 2 cm longer than those of Nipponbare, respectively. Its panicle number per unite area is less than that of Nipponbare. Plant type of this cultivar is super heavy panicle. Its culm is slightly tick and hard, and leaves are smoothness. The awn is few, and its apiculus color is red brown. Grain shattering is slightly easy. 2. Haiminori seems to possess the true resistance gene Pia for blast disease. Its field resistance is superior to Hinohikari, and similar to that of Nipponbare. Its resistance for panicle blast is estimated to be similar to Nipponbare, too. Varietal reaction of resistance to bacterial leaf blight classified into Kinmaze group, and it resistance level is slightly inferior to that of Nipponbare. Haiminori is susceptible to rice stripe disease. Its viviparity is intermediate grade. Tolerance for lodging of Haiminori is slightly superior to that of Nipponbare. 3. In performance tests at the breeding station under transplanting cultivation, yielding ability of Haiminori was similar or slightly inferior to that of Nipponbare. Under direct sowing cultivation on well-drained paddy field, its yielding ability was similar or slightly higher than that of Nipponbare. White core, white belly and chalky rice was occur frequently in Haiminori, its appearance grade of brown rice is remarkably inferior to Nipponbare. Shape and volume of brown rice of Haiminori are similar to Nipponbare, however, its 1000 kernel weight was less than Nipponbare. 4. The weight of embryo of Haiminori occupy about 10% of whole grain, which is 3 to 4 times that of Nipponbare. Gamma-aminobutyric acid (Gaba) which is effective to normalize the blood pressure, acculumates in embryo of soaked brown rice in water. Gaba content of Haiminori reaches to more than 3 to 4 times of Nipponbare and Koshihikari after soaking for 4 hours. In case of milled rice, eating quality of Haiminori is remarkably inferior to that of Nipponbare, however, its eating quality of soaked brown rice for some hours (pre-germinating rice) is almost similar to those of Nipponbare and Koshihikari. Therefore, Haiminori is expected as materials of hearth food diet with aiming the effectiveness of Gaba. 5. Poor seedling establishment is the largest problem in cultivation of Haiminori. Germination rate of Haiminori is stable likewise Nipponbare, however, its emergence rate was less than 40% of Nipponbare. More than 90% of germinated seeds of Nipponbare continue their growth of coleoptile and following leaves, however, 30% of germinated seeds of Haiminori stopped their growth of coleoptile. Occurrence of following leaves of Haiminori is also slower than other ordinary varieties.