Molecular Genetic Diversity Study On68Oversea Sugarcane Germplasm With AFLP Marker Technique

Germplasm is very important for plant breeding. Introduction, collection and evaluation ofsugarcane permplasm are greatly useful for broadening genetic basis and improving breeding efficiencyin sugarcane cross breeding. Oversea sugarcane germplasm plays an important role in sugarcane crossbreeding in China. Aiming at offering useful information for sugarcane cross-breeding and germplasminnovation, Molecular genetic diversity of68oversea sugarcane germplasm, which were fromAustralia(24), France(24), America(12) and Philippines(8) was investigated with the AFLP markertechnique.Based on64AFLP primers,8of68oversea sugarcane germplasm were randomly selected fortesting and screening the better primers and10pairs of AFLP with better Polymorphism were screenedfor investigating molecular genetic diversity of68oversea sugarcane germplasm. A total of1178bands(of which were1013polymorphic bands) were obtained from10pairs of AFLP primers and every pairsof primers can averagely generate101.3polymorphic bands. The PPB (Percentage of PolymorphicBands) is85.76%. PIC (polymorphism information content) of per locus reaches to0.2538and No. ofeffective alleles per locus is1.4.Jaccard similarity coefficient Analysis indicated that the genetic similarity coefficient among68oversea sugarcane germplasm is very high and ranged from0.4975to0.8879with a mean of0.7612.The highest is0.8879between Q90and Q83and the lowest is0.4975between FR94-126and FR94-515.The order of average genetic similarity coefficient is:0.856（Philippines）＞0.802（Australia）＞0.7520（America）＞0.685（France）.Analysis by UPGMA indicated that68oversea sugarcane germplasm were divided into5groups(A-E) with a genetic similarity coefficient0.676. CP67-412, FR94-515, FR96-626, FR94-126belongedto group A-D respectively. The rest (64) falled in the group E with a percentage of94.1%to allgermplasm. The result showed that there was a close genetic relationship and similar genetic componentamong68oversea sugarcane germplasm. Group E can be divided into4subgroups further with agenetic similarity coefficient0.752, namely from subgroup E1to E4. Group E4can be divided into6groups(E4-1-E4-6). The group E4-6included30oversea germplasm with a percentage of44.1%to allgermplasm. Analysis by PCA（Principal component analysis）indicated that68oversea sugarcanegermplasm mainly distributed three areas on the PCA map. The result of PCA is similar with UPGMA.Above results indicated that1. there are close genetic relationship and poor genetic diversityamong the68oversea sugarcane germplasm;2.4germplasm (CP67-412、FR94-515、FR96-626、FR94-126) should be taken important to in sugarcane cross breeding because they are more divergentthan the other germplasm;3. FR germplasm are more divergent and include more genetic informationthan those from the other geographical regions;4. Most of germplasm from America and Philippinesfalled in same group(E4-5) with a high genetic similarity and most of germplasm from France andAustralia falled in same group(E4-6) with a high genetic similarity;5. Germplasm innovation researchshould be enforced further in sugarcane genetic improvement.