| Secale L., one of the relative genera of Triticum, has great potential to be an important genetic resource to increase the genetic variation and introduce desirable genes for wheat improvement. Presently, great achiecements have been accessed in its systematic classification, cytogenetics, molecular genetics and utilization in wheat breeding. For instance, the wheat cultivars carrying 1BL/1RS translation have been successfully used worldwide. However, the genetic diversity of rye has not been investigated as extensively as in other cereals. Evaluation the genetic diversity of plant resources would be useful for their utilization, protecting and reserving valuable and rare genetic resources. The development of molecular biology techniques makes it convenient to evaluate the diversity of genetic resources. The objective of this paper is to investigate the genetic diversity of Secale L. by using ISSR and RAMP markers and to provide valuable information for further utilizationof these genetic resources.1. Genetic diversity of 16 accessions of Secale L., representing 4 species and 8 subspecies, was evaluated using inter-simple sequence repeat (ISSR) markers. Thirty-five ISSR primers were used for the PCR amplification of genomic DNA, and 7 primers (20%) could produce clear and polymorphic bands. A total of 269 bands were amplified from 7 primers, of which 229 bands (about 85.1%) were polymorphic. Seventeen to 70 polymorphic bands could be amplified from each primer, with an average of 32.7 bands. The mean genetic similarity (GS) value based on ISSR markers among 16 accessions of Secale L. was 0.732, ranging from 0.478 to 0.935. All the 16 accessions could be distinguished by ISSR markers.2. According to the clustering results based on ISSR markers, all materials could be classified into 5 subgroups, and S. sylvestre was clearly distinct from the other species. The other species were randomly clustered into 4 subgroups, which indicated a lack of interspecific divergence in the Secale genus. These results gavefurther supports to the conclusions proposed by systematics and molecular biology studies of Secale. These results suggested that S. sylvestre could be classified as one independent species, and ISSR markers could be used as an effective molecular technique for the fingerpringting and systematics study of Secale.3. Genetic diversity of 21 accessions of Secale L., including 3 species and 11 subspecies, was evaluated by using random amplified microsatellite polymorphism (RAMP) markers. Forty-one out of 80 (50.5%) RAMP primers, which could produce clear and polymorphic bands, were selected for the PCR amplification of genomic DNA. A total of 446 bands were amplified from 41 primers, while 428 bands (about 95.9%) were polymorphic. Three to 19 polymorphic bands could be amplified from each primer, with an average of 10.4 bands. The RAMP-based genetic similarity (GS) among 21 Secale accessions ranged from 0.266 to 0.658, with a mean of 0.449. All the 21 accessions could be distinguished by RAMP markers.4. Clustering results indicated that the genetic diversity of Secale based on RAMP markers were correlated with the geographical distribution. Six rye cultivars, originated from Poland, Portugal, Maxico, Hungary, Armenia and Ukraine, were clustered into one subgroup. These countries are all located in the transition region between maritime temperate broad-leaved forest climate zone and continental temperate broad-leaved forest climate zone, with narrow latitude span, In comparison, the five cultivars from other countries, scattering over the region with large latitude span, were distributed within different subgroups.5. These results suggested that higher genetic diversity existed in Secale genetic resources. Both ISSR and RAMP markers could be used as effective molecular techniques to evaluate the genetic diversity of Secale. ISSR markers could reflect the genealogy of Secale and provide useful information for systematic study, while genetic relationships based on RA...
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