Achievements of Upland Rice Breeding in Japan in the Past 77 Years

In 1929, the government breeding program began upland rice breeding research at five breeding stations (Akita, Ibaraki, Mie, Tottori and Kagoshima). Though only Ibaraki Agricultural Center continued upland rice breeding after the post war reorganization, upland rice breeding ended in March 2006 because of a sharp decrease in cultivation area. Sixty-one varieties were bred from 1929 to 2006. Many studies had been carried out on drought resistance and other similar conditions. The achievements of upland rice breeding in each time period are as follows: 1929-1950 The increase of crop production was strongly requested. Upland rice played an important role until farming managements stabilized particularly at reclaimed field. The breeding objectives in this period were mainly high yielding and drought resistance. As a result “Norin 12” which is a high yielding variety with relative short culm and “Norinmochi 26” which is a high yielding glutinous variety and others were released. There were also discussions on basic cultivation studies such as sowing time, sowing quantity and straw mulch effect as well as a variety of screening tests for reclaimed fields suffering from potassium and/or phosphorus deficiency. 1951-1970 The field irrigation systems began to be equipped in upland field, while the increase of crop production was still requested. As the paddy rice was not suitable for upland cultivation due to damage from blast disease, the specific varieties were requested for the cultivation at upland fields with irrigation systems. Therefore breeding was mainly promoted by a cross between paddy rice and upland rice. As a result high yielding varieties such as “Okaminori”, “Mizuhatamochi” and others were released. Additionally many studies on the cultivation methods using field irrigation and cropping systems with wheat or barley cultivation were carried out. 1971-1988 When the overproduction of paddy rice became a serious issue, upland rice began to be used as a rotation crop because it had an effect on the decrease in continuous cropping injury of vegetables. Thus, the breeding of early maturing varieties which made the rotation with vegetable cultivation efficient and were expected to have the effect on drought escape was promoted. As a result early maturing varieties such as “Toyohatamochi” and “Kiyohatamochi” were released and evaluations of deep rooting of foreign upland rice cultivars as well as their utilization as breeding materials were conducted. The greenhouse method for evaluation of drought resistance was also originally exploited. 1989-2005 As vegetable cultivation became more intensive, the very early maturing varieties with high drought resistance were requested for the stable management of crop rotation. As a result, first medium maturing variety “Yumenohatamochi” with deep rooting which was derived from foreign upland cultivar “JC81” was released. Then a very early maturing and stably high yielding variety “Hitachihatamochi” which had the drought resistance acquired from “Yumenohatamochi” and very early maturation and cold tolerance acquired from “Kantomochi 166” was released. Additionally, studies on the processing suitability for the promotion of upland rice consumption were discussed. Based on the idea of using upland rice as a genetic resource, the introgression of blast resistance genes from upland rice into several types of paddy rice by using DNA markers was also promoted.