多年生稻品种遗传改良策略--自1997年开始探索，以亚洲栽培稻为母本和起源于非洲的长雄野生稻杂交，获得具有32.5%自交结实率的F1植株，进而明确了长雄野生稻无性繁殖特性的遗传位点，通过长期自交培育了一批携带这些遗传位点的品系，利用分子标记辅助选择（Molecular Marker Assistant Selection, MAS）技术（图4），把长雄野生稻无性繁殖特性的遗传位点转移到水稻主栽品种中，选育多年生水稻品种（图5）。
There are two serious problems should be solved during the rice production, not only in China, but also in all over the world. Firstly, some environmental problems such as the heavy soil erosion caused by annual rice production (especially for upland rice), although we get high yield (fig 1). Secondly, with the development of economy, the shortage of labor force in rural regions is becoming more and more severe. To solving these issues, the conception of developing perennial rice via transmitting the perenniality of Oryza longistaminata to annual cultivar was conceived (Fig 2).
Perennial Rice, as its name implies, is the rice that could be harvested many years for ideal yield under production condition due to the regeneration of rhizome.
Rhizome of O. longistaminata is the trait of perenniality that was employed to breed cultivar of perennial rice. The purpose and anticipation of perennial rice are to save labors input, decrease chemical fertilizer application, alleviate hard working and reduce soil erosion during rice industry. Perennial Rice technology, including variety and cropping management, is one kind of easy and simply cultivation technique because it is no need seed bought and seeding nursery, no need plough and harrowing, no need transplanting, and crop management needed onlyduring rice production after first rice season.
Research Center for Perennial Rice Engineering and Technology in Yunnan
Research Center for Perennial Rice Engineering and Technology in Yunnan approved by Yunnan Provincial Science and Technology Department in 2016 (Fig 3) is becoming an important platform for perennial rice research andapplication. The joint applicants consist of Yunnan University(YNU)，Yunnan Center of Agricultural Technology Extension (YCATE), Yunnan Academy of Agricultural Sciences(YAAS) and Jinghong Center of Agricultural Technology Extension (JCATE) are responsible for the center. Meanwhile, Dr. Fengyi Hu who is the dean and professor of School agriculture of YNU, was nominated to the director of this center.
Goals--Perennial Rice Technology Research and its Application
Tasks--There are six tasks as following.(1) Basic research of perenniality of O. longisatminata. (2) Genetics and breeding of perennial rice. (3) Cropping management of perennial rice. (4) Farming system reform based on perennial rice. (5) Environment impact of perennial rice technology application. (6) Social economics impact of perennial rice technology application.
Conditions--That conditions including (1) The laboratory (200m2 size) for research and development of perennial rice in Yunnan University, (2) the facilities (1000m2size) for drought tolerance identification in Songming county where is the research station of YAAS and (3) experimental station for breeding in Jinghong where is the agricultural technology extension center of Jinghong, have been established. Meanwhile, the cultivars regional trial and demonstration of perennial rice also have been set up at 19 sites, such as Wenshan, Yuxi, Puer, Xshuangbana, Kunming, Honghe, Dehong, Lincang, Baoshan and so on.
Strategy of Genetic Improvement for Perennial Rice Cultivars--Since 1997, an interspecific hybrid cross RD23/O. longistaminata, between O. sativa cultivar RD23 (an indica cultivar from Thailand) and an unnamed O. longistaminata accession with long and strong rhizomes, originally collected from Niger and kindly provided by Hiroshi Hyakutake (Institute of Physical and Chemical Research, Saitama, Japan), was obtained by direct hybridization followed by embryo rescue and had 32.5% pollen fertility, indehiscent anthers, rhizomes that were intermediate in size, and abundance between the parents. The inheritance of Rhizome using QTL analysis based on a F2 population derived from this cross was explained preliminarily. Thus, the Molecular Marker Assistant Selection (MAS) (Fig 5) and backcross methods was employed to breed the cultivar of perennial rice by transmission the perenniality from O. longistaminata to annual cultivar (Fig 5).
Application of Perennial Rice Technology at Present
Up to now, there are 9 cultivars lines of perennial rice were bred and undergoing regional trial on 16 sites in Yunnan, such as Wenshan, Yuxi, Puer, Xishuangbana, Kunming, Honghe, Dehong, and 8 provinces in south of China, like Zhejiang, Jiangxi, Henan, Hubei, Hunan, Guangxi, Guizhou, Yunnan and Lao’s (oversea). One of lines, PR23 (Perennial Rice 23, similar to its female parent RD23 number) has planted and performed with 7.5t-9.0t and 15.0t-18.0t per ha. in single season and double seasons, respectively, at Mengzhe, south of Yunnan. Perennial rice, succession rice production after first season is obvious for saving ~ 50%input and beneficial to agricultural environment with less chemical fertilizer use and less soil erosion absolutely than annual rice.