(5) A Comparative Study of SRAP, AFLP, and SSR Markers for Detecting Genetic Differences among Elite Broccoli Inbreds

Abstract

Private and public vegetable breeders are interested in using current and emerging PCR-based marker systems in their respective improvement programs. However, before new systems are employed to replace existing ones, the new systems must prove to be efficient and cost-effective alternatives. Sequence related amplified polymorphisms (SRAPs), amplified fragment length polymorphisms (AFLPs), and simple sequence repeats (SSRs) were compared for their ability to differentiate individuals of a diverse group of 24 elite broccoli (Brassica oleracea L. italica) inbreds. Genomic DNA was assayed using 24 AFLP, 24 SRAP, and 44 SSR primer pairs. In this assessment, SSRs produced an average of only two bands per primer, with 25% of these bands being monomorphic, and the remaining bands detecting very few differences among the inbreds. Although the AFLP method resulted in a lower rate (63%) of polymorphism than the SSRs, it produced about 20 bands per primer. SRAPs produced an average of 14 bands per primer, with 82% of these bands being polymorphic. Since AFLP and SRAP markers had a higher multiplex ratio and SSRs were frequently monomorphic, AFLP and SRAPs were more effective in differentiating the elite broccoli inbreds examined in this study. Similarity matrices were generated from the AFLP and SRAP data, and resulting dendographs were compared.