Analysis Of The Distribution Status And Climate Suitable Distribution Areas Of Fortunella In China

Fortunell is an evergreen Citrus fruit tree,which belongs to family Rutaceae and mainly distributed in south of China.It is mainly used in horticulture due to its special shape.Since last few years,the wild resources of Fortunella in China have been decreasing continuously mainly due to lack of tree protection measures especially against diseases as Citrus Huanglongbing.Farmers are not willing to plant this tree due to shortage of disease resistance varieties which is shrinking the commercial cultivation area.Fortunella resource collection work has been carried out in Hunan,Fujian,Guangxi provinces,but optimization of planting scale and distribution of the crop has not become the major concern for regional planning.Therefore,it is of great importance to collect and protect the wild germplasams of Fortunella.It will subsequently increase the rate of germplasam collection and will provide information about the potential distribution areas.The actual geological distribution diagram of six species of Fortunell genus were built by using Arcgis software based on the investigated distribution data including altitude,longitude,latitude and growth-limiting climatic factors,etc.The results had shown that the six species were mainly distributed in south of Dabie-Daba mountain areas with a great number of hills and plains.There was overlapping geological distribution among F.margarita Swingle,F.japonica Swingle and F.crassifolia Swingle.F.obovatta Tanaka was mainly distributed in the south of Jiangsu and Guangxi province,and in the south-east of Sichuan and Zhejiang province with the largest spans.F.polyandra Tanaka was mainly distributed in Hainan,Yunnan,Guangxi and Guangdong province,while the distribution of F.hindsii Tanaka was in Fujian,Guangdong,Jiangxi and Hunan,respectively.Max Ent(Maximum Entropy Model)was used to predict the climate-suitable area of Fortunella in China.The dominant climate factors were screened through Jackknife test.The outcomes have revealed that the climatic conditions of Chongqing,Guangxi,Guangdong,Hainan and south of Yunnan were optimal for F.polyandra Tanaka,while the other five species were pre-dominantly distributed in Hunan,Jiangxi,Guangxi,Fujian,Zhejiang and Guangdong,and some of F.obovata Tanaka even extended to Chongqing.The actual distribution of Fortunella is within the predicted range,and the growth shows that the distribution of Fortunella can be further expanded,which provides a scientific basis to develop and promote economically viable varieties of Fortunella.The introduction value grades of six species were evaluated via analytic hierarch y process based on ornamental value,ability of environment adaption and potential of development.Based on the results,F.crassifolia Swingle,F.margarita Swingle and F.obovata Tanaka are ranked first followed by F.japonica Swingleand F.polyandra Tanaka and F.hindsii Swingle was bottom ranked.