| Current status of wheat breeding in Japan Kimihira FUKUNAGA National Agriculture Research Center, MAFF Yatabe, Tsukuba, Ibaraki 305 Wheat production has been increased to 232 thousand hectares in 1984, with the yield of 3.2 ton/ha, since the bottom of 75 thousand hectares of 1973. The present production is 740 thousand tons which are supplied to the domestic demand at the self-sufficiency of only 12%. Wheat breeding programmes in Japan are conducted at the seven agricultural research stations, including the NARC. The main breeding objectives are early maturity, high yield and good quality for nuddle. The additional objectives are dependent on the climate conditions where wheat is cultivated. The recently bred cultivars (Table 1) show early maturity, short statue and high yield. The genetical control of earliness depends on the insensitivity to daylength and vernalization. Attempts for accumulating the physiological factors with respect to earliness are under investigation. The lodging resistance due to semi-dwarfness realizes the cultural improvement of yield performance under the heavy-fertilized and dense-sowing conditions. There is also the breeding objective emphasized as flour quality. Wheat grains harvested at the rainy season suffer from sprouting, deterioration and high Alpha-amylase activity, resulting in worse flour quality. The genetical and physio-chemical survey on the wheat flour and the nuddle are carried out for a rapid selection of breeding lines. Breeding for disease resistance to leaf rust, yellow mosaic virus, scab, and powdery mildew are important for developing cultivars. Leaf rust resistant genes derived from T. timopheevi and rye were successfully transferred to wheat breeding lines, 'Sabikei 40' and 'Sabikei 43', respectively, which were registered from the Tohoku Nat. Agr. Exp. Sat. in 1984. The selection for resistant plants to yellow mosaic virus is progressed, as the infected plants can be easily distinguished by using ELISA method. The breeding of cultivars with scab resistance has been discussed by Gocho in the ealier paper. Finally, genealogical consideration on pedigrees of Japanese wheat cultivars (FUKUNAGA & INAGAKI 1985) indicates that most clutivars released in the southern part of Japan have been derived from progenies of crosses between only local varieties. Transfer of alien genetic sources from other relative species is positively attempted for future improvement of wheat cultivars. Saving the time required for cultivar development may be accomplished by using doubled-haploid method. MAFF has recently intensified the research activities on genetic resources and biotechnology of crops, which will be studied at the National Institute of Agro-biological Resources. |