Yunnan Wild Rice Resources, Conservation Biology And Genetic Traits

In this study, we investigated, studied, identified and protected the three kinds wildrices (O. rufipogon Griff., O. officinalis Wall. ex Watt., O.granulata Nees et Arn. exWatt.) in Yunnan Province. The field survey showed that they are in the endangeredstatus. O. rufipogon and O. officinalis have only remained one population,respectively. Many natural populations of O. granulata have become extinct duringthe last 30 years and have only 37 remaining wild populations. The mainly reason ofendangered and extinction of wild rice populations is distruction and disappear oftheir habitat due to human activation.The wild rices, as wild relatives of rice, have many excellent genetic characters andgenes. We should have a scientific and effective plan to conserve them. In this study,we innovated a new method for protecting and utilizing wild rice from different levelssuch as molecular, cell, individual and population. First, we have constructed threeBAC libraries, four cDNA libraries and a total DNA library of wild rice in Yunnan.Second, the tissue culture of wild rice has been studied and O. granulata and O.rufipogon can be introduced and differentiated in different culture medium. At thesame time, we have implemented in situ and ex situ conservation to wild rice inYunnan.Oryza granulata is a very important wild rice. In order to evaluate and preserve theendangered wild species of rice, Oryza granulata, we investigated the existingpopulation distribution in Yunnan. The genetic diversity among 14 populations wasstudied using random amplified polymorphic DNA (RAPD) and inter-simplesequence repeat (ISSR) amplification markers. For the study among the 14populations, the percentage of polymorphic bands (PPB) was 59% for RAPDs and64% for ISSRs. However, within populations, the PPB generated by RAPDs andISSRs was avervage 25% and 21%, respectively. The results showed that geneticvariation is much higher among populations of O. granulata than within populations.Therefore, we proposed an appropriate strategy for conserving the genetic resourcesof O. granulata in Yunnan; namely, rescuing and conserving the core populations forin situ conservation, and sampling and preserving more populations with fewerindividuals from each population for ex situ conservation.Yunnan is not only condersidered as one of the original centers of the Asiancultivated rice, but also as one of the centers of its genetic diversity. The geneticdiversity among four different morphological strains and within the Yuanjiangpopulation was studied using random amplified polymorphic DNA (RAPD) andinter-simple sequence repeat (ISSR) amplification markers. The results showed thatgenetic variation is much higher among four different morphological strains ofO.rufipogon than that within the Yuanjiang population. In addition, Yuanjiangpopulation is the most primitive and typical population and is also the highest naturalpopulation of O.rufipogon and distributes in 780 m above see level. Hence, themanagement efforts should certainly focus on the Yuanjiang population. To-date, wehave triggered a plan for in situ conservation of this population. Moreover, the present 4study also reveals that the phylogenetic relationships among O.sativa and O.rufipogonaccessions in Yunnan are monophyletic evolution. Namely, the japonica rice was aderivative type from the indica rice due to adapting to its unique environments. Ouranalysis showed that the indica rice has more extensive genetic diversity than thejaponica rice, although the japonica rice disseminated to more extensive regions andadapted to broader ecological conditions. In addition, compared to the cultivated rice,O.rufipogon in Yunnan show more genetic variations. This result suggested that manygenes of common wild rice were already lost in cultivated rice during the longdomestication. The purpose of protecting wild rice is to employs the natural gene pool. For thisobject, the systema...