Physical Localization Of 17 Markers In The Linkage Group 4 And 15 Of Genetic Map Of Hevea Brasiliensis

Hevea brasiliensis,a perennial tropical tree of the Euphorbiaceae family,is the major commercial source of natural rubber.In this study,17 RFLP markers,belonged to linkage group 4 and 5 of Hevea brasiliensis genetic map constructed by Lespinasse in 2000,were mapped onto the chromosomes of Reyan "7-33-97"(Hevea brasiliensis cultivar)by fluorescence in situ hybridization(FISH).After karyotype analysing,the locations of these genetic markers on the chromosomes,as well as the correspondence between the linkage groups and the chromosomes,were determined.The results will lay the foundation for the construction of molecular cytogenetic map of the rubber tree,and will provide the scientific basis for rubber tree molecular assisted breeding,identification of germplasm resources and comparative genomics.The results were as follows:(1)According to karyotype analysis,11 genetic markers were located on chromosome 9 of the Reyan "7-33-97" cultivar by FISH.The linkage group 4 corresponded to chromosome 9.The three markers(gHbCIR131,gHbCIR326,gHbCIR144)were all located on the short arm,and the average percentage between the signal loci and chromosome centromeres were 75.52,56.26 and 38.98,respectively.Other 8 markers(gHbCIR381,gHbCIR35,gHbCIR639,gHbCIR529,gHbCIR660,gHbCIR344,gHbCIR88,gHbCIR403.L1)were located on the long arm,the average percentages between the signal loci and chromosome centromeres were 24.96,31.37,36.72,44.65,46.01,48.01,53.14 and 54.32,respectively.(2)FISH detection was performed on six markers from the linkage group 15,the results showed that three genetic markers(gHbCIR542,gHbCIR494,gHbCIR436)were located on the short arm of chromosome 10,and the average percentages of signal loci to chromosomes centromeres were 53.53,44.75 and 35.07,respectively.The markers gHbCIR167,gHbCIR139,and gHbCIR441 were located on the long arm of chromosome 10,and the average percentages of signal loci to the chromosomes centromeres were 45.32,46.07 and 62.83,respectively.It indicated that linkage group 15 corresponded to chromosome 10.(3)The cytogenetic map of chromosomes 9 and 10 of Hevea brasiliensis was constructed.The linear order of the most genetic markers in the map was the same as in the genetic map.