Allelopathic effects of Triticum speltoides on two important weeds of wheat

Abul HashemA,B and Steve W. AdkinsA

A Department of Agriculture, University of Queensland, St. Lucia, Queensland 4072, Australia.

B Currently: Dryland Research Institute, Agriculture WA, Merredin, Western Australia 6415, Australia.


The allelopathic effect of seven accessions of Triticum speltoides L. (a wild relative of wheat) on Avena fatua L. (wild oats), nine accessions on Sisymbrium orientale L. (Indian hedge mustard) and ten accessions on both species was evaluated using an agar diffusion method. This study was conducted as part of a broader attempt to evaluate the suitability of T. speltoides as a donor of an allelopathic trait to wheat to produce a new cultivar with weed suppressing ability. Pre-germinated seedlings of surface sterilized caryopses of T. speltoides were transplanted on to an agar (5 g L-1) surface contained within a tube of cellulose dialysis membrane. The tube of cellulose dialysis membrane was held vertically within a 1.5 L plastic box partially filled with 1 L of agar (5 g L-1). Surface sterilized caryopses of A. fatua or seed of S. orientale were sown onto the agar surface of the box at various distances from the T. speltoides seedling.

Following two or six weeks (for A. fatua and S. orientale, respectively) the weed seedlings were removed from the agar and their radicle lengths recorded. Among the 17 T. speltoides accessions tested against A. fatua, accession 9 was the only one that significantly reduced radicle length (50%) across the width of the plastic box. Among the 19 accessions of T. speltoides tested against S. orientale, accession 8 (50%) and accession 10 (18%) were the only ones that significantly reduced length across the width of the plastic box. None of the accessions tested had the ability to suppress radicle growth of both weed species.


Plant Protection Quarterly (1998) 13 (1) 33-35.