Evaluation of seedling allelopathy in 453 wheat (Triticum aestivum) accessions against annual ryegrass (Lolium rigidum) by the equal-compartment-agar method

Abstract

Allelopathy has been receiving world-wide attention for its potential in integrated weed management. A newly developed screening bioassay, the ‘equal-compartment-agar method’ (ECAM), was used to evaluate seedling allelopathy against annual ryegrass in a collection of 453 wheat accessions originating from 50 countries. Significant differences in allelopathic potential were found in this worldwide collection, inhibiting root growth of ryegrass from 9.7% to 90.9%. Wheat seedling allelopathy also varied significantly with accessions from different countries. Wheat allelopathic activity was normally distributed within the collection, indicating the involvement of multiple genes conferring the allelopathic trait. Of the 453 wheat accessions screened, 2 distinct groups were identified. Condor-derivatives were more allelopathic than Pavon-derivatives, with an average inhibition of root growth of ryegrass by 76% and 46%, respectively. Research was further extended to investigate the near isogenic lines derived from Hartog (Pavon-derivative) and Janz (Condor-derivative). Hartog and its backcrossed lines were less allelopathic than Janz and its backcrossed lines, inhibiting root length of ryegrass by 45% and 81%, respectively. These results strongly indicate that wheat allelopathic activity might also be controlled by major genes, depending on the particular populations. The present study demonstrates that there is a considerable genetic variation of allelopathic activity in wheat germplasm. It is possible to breed for cultivars with enhanced allelopathic activity for weed suppression.

Effects of wheat-canola intercropping on Phelipanche aegyptiaca parasitism

“…The results of the current study are broadly in agreement with those of Wu et al (2000Wu et al ( , 2001, who also found a significant genetic variation of weed growth inhibitory activity in wheat and reported that wheat allelopathic activity is genetically controlled, and a multigenic model is involved in wheat allelopathy.…”

Quantitative trait loci and molecular markers associated with wheat allelopathy

“…Although cv Tasman was strongly allelopathic, cv Sunco belonged to the intermediate allelopathic groups (Wu et al 2000a). To verify these initial results on the genetic control of wheat allelopathy, it is necessary to construct new mapping populations derived from two extreme allelopathic groups, i.e.…”

“…Recent research has generally shown that allelopathic activity is quantitatively inherited in rice and wheat (Dilday et al 1998;Wu et al 2000a). Wu et al (2000a) found that wheat-seedling allelopathy on L. rigidum was normally distributed in the collection of 453 wheat accessions, indicating that this weed-suppressing ability is a quantitative trait. The genetic control of allelopathic activity was further studied using near-isogenic wheat lines derived from Hartog (weakly allelopathic) Janz (strongly allelopathic).…”

“…Wu et al (1998) found that wheat residue allelopathy differed significantly on the suppression of annual ryegrass among accessions. Further study showed that root exudates of wheat seedlings inhibited root growth of annual ryegrass over a range from 10% to 91% in a worldwide collection of 453 wheat accessions, and the allelopathic activity of wheat seedlings on ryegrass was not correlated with wheat competitive parameters, such as the plant height and root length of wheat seedlings (Wu et al 2000a).…”

In vitro allelopathic effect of aqueous extracts of sugarcane on germination parameters of wheat

“…Allelochemicals are generally secondary metabolites present in different concentrations in different plant parts (leaves, stem, barks, flowers, seeds etc.) which upon release into the rhizosphere tend to modify the resource consumption capacity by several mechanisms i.e., alteration of cell membrane permeability, changing enzymatic activity, triggering genetic defects and disturbing photosynthesis of the competitor plants (Gonzalez and Estevez-Braun, 1997;Wu et al, 2000;Barto et al, 2010;Majeed et al, 2012). Interactions among plants for resources through allelopathy lead to physiological and biochemical modifications which may result in the establishment of a successful plant community by eliminating or restricting the susceptible species, although many plants exhibit positive allelopathic effects on the surrounding plants (Elijarrat and Barcelo, 2001;Maharjan et al, 2007;Hussain et al, 2010).…”