Analysis Of Genetic Diversity Of Citrus Grandis Osbeck In Western Hubei By RAPD And ISSR Markers

China is one of the centre of origin, inheritance and variation of Citrus. The germplasm resources of pummelo( Citrus grandis Osbeck) contains abundant variations. The genetic diversity of Citrus in western Hubei province was studied based on RAPD and ISSR molecular markers.1. According to the common procedures of molecular markers of RAPD and ISSR, some modifications had been adjusted , such as DNA extraction and PCR system, etc. The result was to set up the reaction system of RAPD and ISSR fitting for analyzing the resources of pummelo in western Hubei. RAPD reaction system: DNA(20ng/(aL), primer (l//mol/L), MgCh(1.5mM), TaqDNA polymerase 1.5U, dNTPs(200umol/L), PCR program: 944min, 1 cycle; 94lmin, 35lmin, 722min, 40 cycles; 727min, 1 cycle. ISSR reaction system: DNA(20ng//uL), primer (l^mol/L), MgCh(2.0mM), Ta^DNA polymerase 1.5U, dNTPs(200^mol/L); PCR program: 944min, 1 cycle; 94癈40s, 48-5660s, 722min, 30 cycles; 727min, 1 cycle.2. Twenty-two primers of 10 base pair were screened out from 120 random primers and were used to analyze with RAPD among 56 accessions, which generated 207 bands, of which polymorphic bands number was 104, the percentage of polymorphism equaled 50.2%; 13 primers, which could amplified clearly bands, were screened out from 100 ISSR primers. As a result, 136 bands were generated, of which polymorphic bands number was 82, the percentage of polymorphism was 60.3%. The conclusion indicated that ISSR is more effective than RAPD.3. According to the clustering analysis of RAPD and ISSR's results, it proved that there were large inherited differences among all kinds of pummelos resources. Moreover, there were obvious difference among 'shatian' pummelo. Two types of 'shatian' pummelo, 'chang shou' and 'guang xi', belong to different groups. At the same time, it could be observed that there were much inherited difference among the local 'shatian' pummelo of western Hubei.The research proved that RAPD and ISSR molecular markers could show the genetic diversity among all sorts of Citrus grandis Osbeck resources well, identify the varieties and analyze the inherited relations each other between the closer inherited distance types. Also it discussed the analyses of technologies as well as systems of RAPD and ISSR, providing some suggestions for the protection of pummelos in western Hubei province.