Allelopathy, DIMBOA production and genetic variability in accessions of Triticum speltoides

A screening was conducted to study the allelopathic potential of Australian -held accessions of Triticum speltoides. Of 26 accessions, four were found to inhibit root growth in the indicator species,lettuce (Lactuca sativa). T he methanol leaf extracts of these accessions significantly reduced the roo t length of wild oat (Avena spp.). In all but one case, alellopathic access ions contained higher amounts of DIMBOA than did nonallelopathic accessions . Since some variation in allelopathic response was detected within lines, random amplified polymorphic DNA (RAPD) markers were used to estimate genet ic diversity between and within the allelopathic accessions of Triticum spe ltoides L. The average genetic similarity between all possible pairs of sel ected accessions was found to be 55% and ranged from 44% to 88%. Comparison of DNA extracted from different single seedlings within the same accession revealed significant intraaccession genetic diversity (4-24%), although th is was much less than that observed between accessions tested. This intraac cession diversity has significant implications for the selection of T. spel toides accessions in breeding or screening programs.