ISSR Analysis And In Vitro Conservation Of The Wild Bananas From Fuzhou And Quanzhou Cities

In this experiment ISSR analyses of7populations of the wild bananas fromFuzhou City (Qishan Mountain in Minhou County, Beifeng Mountain and HuanxiMountain in Jinan District) and Quanzhou City (Dehua County and Yingchun County)were carried out for studying the genetic diversity; and then a preliminary study onthe in vitro conservation of the wild banana from Qishan Mountain was conducted.The main results were as follows:1. ISSR analysis on7populations of the wild banana resources from Fuzhou andQuanzhou Cities.The genomic DNA of289samples of the wild bananas（Qishan wild banana,Population1,NO.1-48; Beifeng wild banana, Population2, NO.49-88; the low-altitudeHuanxi wild banana, Population3,NO.89-125; the middle-altitude Huanxi wildbanana Population4,NO.126-166; the high-altitude Huanxi wild banana, Population5,NO.167-214; Dehua wild banana, Population6,NO.215-246; Yongchun wildbanana, Population7,NO.247-289）in Fuzhou or Quanzhou City were extracted fromthe leaves for ISSR analyses.16primers were screened from40arbitrary primers, anda total of174DNA bands were amplified, among which121（69.54%）werepolymorphic. The Nei’s genetic distance and the genetic similarity coefficient of7populations of the wild banana resources were at0.0662-0.2437and0.7837-0.9335,respectively. The results showed that the population1had the highest polymorphism,with PPB=45.4%，ne*1.2612±0.3539，H=0.1536±0.1937，I=0.2307±0.2796. Thepopulation2had the lowest polymorphism with PPB=17.24%, ne*=1.0873±0.2264,H=0.0534±0.1312, I=0.0816±0.1944. Compared with the similar studies, the geneticdiversities of Fuzhou and Quanzhou wild bananas were at relatively low levels, whichmeant that these wild bananas had faced dangerous survival problems, and these wildbananas should be protected most urgently.The cluster analysis results of ISSR markers of the289samples of the wildbananas showed that: at D1=21.5district,289samples of wild bananas resources were divided into two distinct groups: the first group was the population1, and thesecond group included all the other populations; at D2=18.0district, the first groupwas divided into two subgroups, the No.44sample of the Qishan wild bananabelonged to a special subgroup, and the other47samples belonged to the othersubgroup; at D3=15.5district, the second group was divided into2small groups:the first small group was Dehua wild banana, and the second small group includedBeifeng wild bananas, Yongchun wild banana and Huanxi wild banan; at D4=13.0district, Beifeng banana and Yongchun wild bananas were assigned to one smallsubgroup, and the low-altitude Huanxi wild banana, the middle-altitude Huanxi wildbanana and the high-altitude Huanxi wild banana were assigned to another smallsub-group. Beifeng wild banana and Yongchun wild banana had close geneticdiatance, although they were not close in geographic location, which was an exceptionin this xperiement. The low-altitude Huanxi wild bananas, the middle-altitude Huanxiwild banana and the high-altitude Huanxi wild banana came from the same mountain,and they were very similar.At D5=11.5district, the low-altitude Huanxi wild banana was divided into aseparate category, the middle-altitude Huanxi wild banana and the high-altitudeHuanxi wild banana were assigned into another category. The low-altitude Huanxiwild banana had the higher polymorphism than the middle-altitude and high-altitudeHuanxi wild bananas did. The middle-altitude Huanxi wild banana and thehigh-altitude Huanxi wild banana had the closer genenetic distance. At D6=10.2district, the middle-altitude Huanxi wild banana and the high-altitude Huanxi wildbanana were divided into two category. The above results showed that Fuzhou andQuanzhou wild bananas had a close relationship in genetic relationship andgeography.The effective number of alleles in7populations was1.1364, Nei’s genediversity index was0.0785, and Shannon’s information index was0.1167, Ht=0.1835,Hs=0.0865, Gst=0.5824, Nm*=0.4462. The inter-populations variance was58.24%and inside-population variance was41.76%. Nm*was0.4462﹤0.5, which suggestedthat the population could not maintained higher genetic diversity. It was probablethat that lower gene exchange of populations, inbreeding depression, partial asexualreproduction and population isolation resulted in genetic differentiation of the7populations. A plant population only has a higher genetic diversity, it can survive inthe evolution. It was difficult for Fuzhou and Quanzhou wild bananas to maintain the higher diversity of genetic variance, which suggested that they should be furtherprotected for reduction of population isolation and promotion of gene exchangeamong populations to ensure the survival of the wild bananas.2．In vitro conservation of the wild banana.The above results showed that Qishan wild banana were widely distributed andwith the highest genetic diversity, therefore it was selected as the material for thepreliminary study on the in vitro conservation of the wild banana. Seeds were used asthe experimental material, and MS culture was used as the basal medium, and theeffects of different sterilization methods on the rates of contamination, the effects ofseed maturity,4℃treatment and the concentrations of6-BA and NAA on thegermination rates were compared. The results showed that0.1%HgCl2for9min wasthe best disinfection way, and mature seeds had the highest germination percentage.The suitable medium for in vitro conservation was MS+6-BA0.5mg/L+NAA0.1mg/L+Agarose0.6%+Sucrose3%, pH5.8.