Submitted to: Revista Brasileira de Sementes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/2002
Publication Date: 4/1/2003
Citation: Menezes, C.C., Vantoai, T.T., Mcdonald, M.B., Sediyama, E.T. 2003. Sequence characterized amplified region (scar) technique used for variety discrimination in vinca (catharanthus rosues l.). Revista Brasileira de Sementes. 24:299-305.
Interpretive Summary: A large number of plant varieties are being developed and released that sometimes differ only in one single gene. Testing for genetic purity and variety discrimination is becoming a more difficult and complex task. The PCR-based Random Amplified Polymorphic DNA (RAPD) technique had led to a new generation of molecular marker-based genetic purity determination. The low stringency requirements of RAPD, however, can cause non- reproducible results. This paper reports the development of SCAR (Sequence Characterized Amplified Region) markers for varietal identification of vinca, an ornamental plant. The technique is reproducible and compatible with DNA isolated from dry seeds, a very important feature in improving the efficiency of a seed-quality evaluating program.
Technical Abstract: Sequence Characterized Amplified Region (SCAR) appears as a useful technique for seed genetic purity testing and variety discrimination, applicable to species in which other techniques have failed. In particular, this technique is very attractive with species in which RAPD results were not consistent. The RAPD polymorphic bands were cloned, sequenced and from the sequence information, primer pairs for normal PCR were developed. Since the probability of obtaining successful SCAR primers from RAPD polymorphic bands was about 50%, a larger number of RAPD polymorphic bands are needed to develop sufficient SCAR primers for varietal discrimination in vinca. In addition, the efficiency of the SCAR technique is strongly affected by the quality of DNA extracted from seeds. The SCAR banding patterns obtained from vinca seeds were consistent and repeatable making the results reliable for genetic purity testing and variety discrimination. The SCAR technique is simple, fast, and relatively inexpensive. It also allows the use of DNA extracted from dry seeds, a very important feature in improving the efficiency of a seed-quality evaluating program.