Molecular identification and genetic variation of varieties of Styphnolobium japonicum (Fabaceae) using SRAP markers.

Thirty-four Styphnolobium japonicum varieties were analyzed using sequence-related amplified polymorphism (SRAP) markers, to investigate genetic variation and test the effectiveness of SRAP markers in DNA fingerprint establishment. Twelve primer pairs were selected from 120 primer combinations for their reproducibility and high polymorphism. We found a total of 430 amplified fragments, of which 415 fragments were considered polymorphic with an average of 34.58 polymorphic fragments for each primer combination. The percentage of polymorphic fragments was 96.60%, and four primer pairs showed 100% polymorphism. Moreover, simple matched coefficients ranged between 0.68 and 0.89, with an average of 0.785, indicating that the genetic variation among varieties was relatively low. This could be because of the narrow genetic basis of the selected breeding material. Based on the similarity coefficient value of 0.76, the varieties were divided into four major groups. In addition, abundant and clear SRAP fingerprints were obtained and could be used to establish DNA fingerprints. In the DNA fingerprints, each variety had its unique pattern that could be easily distinguished from others. The results demonstrated that 34 varieties of S. japonicum had a relatively narrow genetic variation. Hence, a broadening of the genetic basis of breeding material is necessary. We conclude that establishment of DNA fingerprint is feasible by means of SRAP markers.

Induction and identification of Stylosanthes guianensis tetraploids.

Stylosanthes guianensis is an elite and important forage legume species, which is extensively cultivated in tropical areas. Polyploid breeding via exposure to colchicine is a conventional and practical method to improve varieties of S. guianensis. Terminal buds of S. guianensis Reyan No.5 seedlings were treated with different concentrations of colchicine (0.00, 0.05, 0.10, 0.15, 0.20, and 0.25%) for 24, 48, and 72 h. Morphological and cytological variants were observed at a frequency of <96% among transplanted seedlings. The cytogenetic analysis of young leaf cells was conducted on all variants to identify their ploidy levels. The most efficient procedure for tetraploid production was the treatment of seedling apical buds with 20% colchicine for 48 h, with the tetraploid induction rate being 10%. This is a relatively simple and reliable method for the production of tetraploidy in S. guianensis.