'Milky princess', a new rice [Oryza sativa] cultivar with low-amylose content in endosperm

'Milky Princess' is a new paddy rice cultivar with low-amylose content in the endosperm that was developed by the National Institute of Crop Science in 2002. This cultivar was selected from a cross between 'Kanto 163' and 'Ko 272' conducted in 1991. 'Kanto 163' is a promising line that harbors the rice stripe virus resistance gene, Stvb-i. 'Ko 272' is a sibling line of a low-amylose content cultivar, 'Milky Queen', and the low-amylose content in the endosperm is controlled by the novel allelle Wx-mq on the Wx locus. Line 'Kanto 194' was selected from the cross at the Fsub(5) generation. 'Kanto 194' has been subjected to local adaptability tests since 1997. It was officially registered as 'Milky Princess (Paddy Rice Norin 387)' by the Ministry of Agriculture, Forestry and Fisheries of Japan in 2003. Its main characteristics are as follows; 'Milky Princess' is a non-glutinous cultivar with dull endosperm, of which the grain appearance can be readily distinguished from that of the waxy and non-glutinous endosperm. The dull endosperm is controlled by the Wx-mq gene and the amylose percentage in the endosperm is about 9%. Therefore, the cooked rice of 'Milky Princess' is sticky and its eating quality is comparable to that of 'Milky Queen' or 'Koshihikari', the finest cultivars for eating quality in Japan. The heading and maturing dates of 'Milky Princess' are 2 days earlier than those of 'Milky Queen'. So, its maturity is classified as 'early' in the Kanto region. The lodging resistance of 'Milky Princess' is superior to that of 'Milky Queen' and classified as 'strong'. Its yield of brown rice is about 10% less than that of 'Milky Queen'. 'Milky Princess' possesses the Stvb-i gene and shows resistance to the rice stripe virus. DNA diagnostic tests of the two genes Wx-mq and Stvb-i have already been established (Patents No. 3569746 (Sato et al. 2002) and No.3069662 (Saito et al. 1999)). With the exception of 'Milky Princess', no other cultivars harboring both genes have been developed. It is possible to identify 'Milky Princess' at the molecular level using the two diagnostic methods mentioned above.