The Application Of TRAP To Evaluation Of Diversity On Cotton Germplasm Resources

Cotton is an important industrial crop worldwide and plays an important role in national economy. In order to improve the quality of raw cotton in our country and competition in the international market, it is necessary to develop varieties with combination of good quality in fibre length, strength and micronaire. Therefore, it is important to innovate and detect new germplasm resources.The study of genetic diversity is beneficial to the collecting and protecting of rare gene resources, as well as to the exploitation of gene resources. The development of the molecular biotechnology has provided more convenience for the further systematic evaluation of gene resources.This study evaluated the genetic diversity of 65 cotton germplasm resources by using TRAP(Target Region Amplification Polymorphism) molecule marker. The main results are as follow:1.Obtained TRAP-PCR reaction system and program sutable for cotton. TRAP-PCR reaction system: The amplification solution(15μl) was consisted of 48 ng template DNA, 0.9 mmol/L Mg2+,1.26 mmol/L dNTP, 0.5μmol/L fixed primer, 0.1μmol/L arbitrary prime and 0.75 U Taq polymerase. TRAP-PCR reaction program: First, predenature at 94℃for 4 minutes, second, 5 cycles denature 94℃for 45 second,annealing 35℃for 45,extension 72℃for 1 minutes. Then, 35 cycles of denature 94℃for 1 minutes,annealing 52℃for 1 minutes, extension 72℃for 1 minutes.Finally, it extension 72℃for 7 minutes,and stored at 4℃.2.Genetic diversity of 65 lines of cotton germplasm was evaluated using TRAP markers. A total of 252 bands were amplified from 10 pair of primers, of which 210 bands (about 83.33%) were polymorphic. An average of 21 bands could be amplified from each pair of primers. The 65 lines of cotton germplasm were clustered into six groups at GS = 0.8431 by using UPMGA in NTSYS-pc Version2.11 program. TRAP markers can distinguish 61 from 65 lines of cotton germplasm.3.Clustering results indicated that genetic diversity of cotton germplasm based on TRAP markers were have some relationship with the morphologic characteristics and geographical distribution. In a word, TRAP is not only can detect genetic diversity in cotton, but also applied to the study genetic background of cotton. 4. The special fragments on Xin Hai 16 and Xin Hai 20, obtained with different primer combinations, were sequenced .Their accurate length of the five specific fragments(T1,T2,T3.1,T3.2,T4) were : 311bp,126bp,494bp,346bp和292bp respectively. These offer effective approach for molecular identification of Xin Hai 16, Xin Hai 20 and its hybrid progeny with upland cotton.