Weed pressure determines the chemical profile of wheat ( Triticum aestivum L.) and its allelochemicals potential

Abstract

BACKGROUND: Common purslane (Portulaca oleracea) and annual ryegrass (Lolium rigidum) are important infesting weeds of field crops. Herbicides are mostly used for weed suppression, while their environmental toxicity and resistance in weeds against them demand considering alternative options, such as the use of allelopathic crops for weed management. Wheat is an important allelopathic crop and present research focused on the identification and quantification of benzoxazinoids (BXZs) and polyphenols (phenolic acids and flavonoids) of the wheat accession ‘Ursita’ and to screen its allelopathic impact on P. oleracea and Lolium rigidum through equal-compartment-agar (ECA) method. RESULTS: Weed germination, radicle length, biomass and photosynthetic pigments were altered following co-growth of weeds with Ursita for 10-day. Root exudates from Ursita reduced (29–60%) the seedling growth and photosynthetic pigments of Lolium rigidum depending on co-culture conditions of planting density. Weed pressure caused significant increase in the production of phenolic acids (vanillic, ferulic, syringic and p-coumaric acids) and root exudation of BXZs, in particular benzoxazolin-2-one (BOA), 2-hydroxy-7-methoxy-1,4-benzoxazin-3-one (HMBOA), 2-hydroxy-1,4-benzoxazin3-one (HBOA) and 2,4-dihydroxy-1,4-benzoxazin-3-one (DIBOA) in wheat tissues (shoots, roots) and exudate in root rhizosphere agar medium in response to co-cultivation with Lolium rigidum and P. oleracea, depending on weed/crop density. CONCLUSION: The work revealed that Ursita is allelopathic in nature and can be used in breeding programs to enhance its allelopathic activity. Meanwhile, there are opportunities to explore allelopathic effect of wheat cultivars to control P. oleracea and Lolium rigidum under field conditions. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.