GENETIC DIVERSITY IN AUSTRALIAN WHEAT-VARIETIES AND BREEDING MATERIALBASED ON RFLP DATA

Restriction fragment length polymorphisms (RFLPs) have been used to ch aracterise the genetic diversity of wheat (Triticum aestivum) germplas m, One hundred and twenty-four accessions comprising all major Austral ian wheat varieties and lines important for breeding purposes were ass ayed for RFLPs with clones of known genetic location and selected to g ive uniform genome coverage. The objectives of this study were to dete rmine RFLP-based genetic similarity between accessions and to derive a ssociations between agronomically significant traits and RFLP phenotyp es. Ninety-eight probes screened against genomic DNA digested with fiv e restriction endonucleases detected a total of 1968 polymorphic fragm ents, Genetic similarity (GS) calculated from the RFLP data ranged fro m 0.004 to 0.409 between accessions, with a mean of 0.18. Cluster anal ysis based on GS estimates produced four groupings that were generally consistent with available pedigree information, Comparisons of the RF LP phenotypes of accessions containing disease resistance genes presen t on introgressed alien segments enabled the identification of specifi c alleles characteristic of these regions. Associations were derived f or a range of stem-rust, leaf-rust and yellow-rust resistance genes, T hese results suggest that RFLP analysis can be used for the characteri sation and grouping of elite breeding material of wheat and RFLP profi ling can identify chromosome segments associated with agronomic traits .