The Reaserch Of Aluminum Tolerance Identification,Genetic Analysis And Molecular Markers In Centipedegrass

Centipedegrass (Eremochloa ophiurides) belongs to the genus Eremochloa in Gramineae and is the only specis used as turfgrass in the genus. Centipedegrass is widely distributed in central and south China. Different distribution of the genetic resoures might exist great differences in aluminum resistance. However there are few researches about the aluminum tolerance of centipedegrass. In the study,92accessions of centipedegrass from13provinces of China and2American cultivars were used to the aluminum tolerance evaluation. Based on the assessment, and combined with the former study on the SRAP diversity of these centipede grass avvessions, the association analysis was conducted to find the molecular markers closely linked with the aluminum tolerance. In the presence of centipedegrass source for parents prepare hybridized combinations. The aluminum tolerance of73hybrids between two centipede grass with different aluminum tolerance were indentified and the major gene and polygene mixed genetic model was used to analyze the genetic character of the aluminum tolerance. On this basis,QTL linked to the trait was mapping in the map which had finished. The results were reported as follows:1Variation of Al tolerance in germplasm resources of centipedegrass in ChinaThe small-volume solution culture method was used in the study to conduct an evaluation on the aluminum tolerance of92centipedegrass accessions with two cultivars ’TifBlair’and’Common’from USA as the check to study the aluminum tolerance differences among the different accessions of centipede grass and select the centipede grass accessions with Al-tolerance for futher genetic improvement. The results indicated that significant growth differences were found among94centipedegrass accessions under1.5mM Al stress, and the CV of relative root weight, relative shoot weight, and relative total weight were21.63%,]6.4%and16.57%, respectively. Using the method of membership function values,94centipedegrass accessions were classified into five levels of aluminum tolerance, in which the accessions number of1-3level (Al tolerance type) were26, accounting for27.7%of total accessions, the accessions number of level5(Al sensitive type) were37, accounting for39.3%of the total accessions, the accessions number of level4(Intermediate Al tolerance type) were31, accounting for33%of total accessions.’TifBlair’and’Common’ are intermediate types, indicating the potential for developing the genetic resource of aluminum tolerance in centipedegrass is great and promising.2The genetic analysis of Al-tolerance in centipede grassF1segregating populations were obtained from two accessions of cenipedegrass [E102and E092(1)] with different aluminum tolerance in order to study the genetic character of the aluminum tolerance in centipedegrass. The relative root dry weight, relative shoot dry weight, relative to whole plant dry weight of F1groups of73offspring and the parents were tested and analyzed to identify their aluminum resistance. The membership function value for the index of73true hybrids, together with their parents were analyzed for the aluminum tolerance by using the Major Genes and Polygenes Genetic Analysis method. The result shows that the CV of membership index value, relative root weight, relative shoot weight, and relative total weight were42.28%,25.36%,21.76%and20.15%respectively. The best model for aluminum tolerance of this population was model A-0, namely that this character was controlled by no major gene. The study clarifies the genetic character of aluminum tolerance traits in centipedegrass and provides scientific basis for aluminum tolerance gene and QTL positioning and marker assisted breeding.3SRAP markers closely linked of centipede grass aluminum tolerance3.1Correlation analysis of SRAP markers and centipede grass aluminum toleranceThe39pairs of SRAP primers were used to conduct the whole genome scanning for the94accessions of centipedegrass resource and the correlation analysis of aluminum tolerance in centipede grass was analyed by the software TASSEL2.1GLM method based on the analysis of groups of linkage disequilibrium level. The results show that, some degree LD exist between the SRAP marker loci. However, counterpoint between statistical probability(P<0.01)support the unbalanced paired proportion is small, only reach0.602%in loci combineation of centipedegrass. The use of SRAP data analysis, centipede grass source groups results can be divided into2subsets. At the P<0.05level, a total of9SRAP marker loci were associated with A1resistance, in which4marker loci was significantly correlated with the relative root dry weight,5marker loci was significantly correlated with the relative shoot dry weight, and5marker loci was significantly correlated with the relative whole plant dry weight, and2marker loci was significantly correlated with the membership function value for the index.3.2Centipedegrass aluminum tolerance of QTL positioning researchThe aluminum tolerance QTL of centipedegrass was located in the genetic linkage map with WinQTLCart software by using composite interval mapping method. The results show that, only the relative root dry weight in the three aluminum tolerance traits was detected in1QTL, which located in the maternal genetic mapping of linkage group LGF1, position343.26cM, and nearest to the labeled SRAP1432.