A new rice [Oryza sativa] variety 'Koshikagura'

In the breeding program aiming at developing rice varieties with useful grain characteristics for sake brewing, we bred a new rice variety, Koshikagura, at the Hokuriku Research Center of the National Agricultural Research Center. This variety is a non-glutinous rice variety, with many white core grains, and high tolerance to hard grain milling. Koshikagura was bred from the progeny of a cross between Yamadanishiki and Hokuriku 174 in 1996. Yamadanishiki is a Japanese major variety for sake brewing, and Hokuriku 174 is a variety for staple food with useful characteristics for cultivation. From the Fsub(12) progenies, we selected one promising line and named Hokuriku sake 206, and submitted the line to various locations for evaluating local adaptability, Hokuriku sake 206 was officially registered in MAFF and in 2007 it was named as Koshikagura. Agronomic characters of Koshikagura evaluated are as follows. The heading date is 6 days earlier than Nipponbare and the ripening date is 8 days earlier than that variety. Comparing to Nipponbare, the culm length is about 10 cm longer, the panicle length is slightly shorter and the panicle number is slightly less. The plant type of this variety is classified into middle type. This variety has low tolerance to lodging. The grain shattering of Yamadanishiki, the parental variety, was improved in this variety. Grain yield is almost same as Nipponbare, it is enough for using for brewing sake. The thickness of brown rice is estimated to be about 2.09mm and 1000-kernel weight is estimated to be about 25g, and both of these values is slightly larger than common rice varieties for staple food. This variety contains many white core grains. When rice is milled to 45%, percentage of crashed rice of Koshikagura is lower than Yamadanishiki. It reveals that Koshikagura have high tolerance to hard grain milling. The rate of water absorption was slightly lower than Yamadanishiki, and the titer of the malted rice is almost same as that variety. When brewing is conducted, both alcohol yield and the amino acidity are almost same as Yamadanishiki. Taste and flavor of the sake brewed from Koshikagura are evaluated to different type to the sake brewed from Gohyakuman-goku or Yamadanishiki. So, the development of the new quality sake brewed from the finest rice which used Koshikagura is planned. Koshikagura is estimated to possess true blast resistance genes, Pia. The field resistances for both leaf and panicle blast is judged to be moderate resistance. Tolerance to sprouting is semi-hard, and cool weather tolerance is semi-weak. Koshikagura can be grown in a region from South -Tohoku area to Kyushu area of Japan for brewing sake.