Phenolic compounds and allelopathic activities of ancient emmer wheats: perspective for non-chemical weed control scenarios

Abstract

Phenolic compounds are natural phytotoxins which play role as chemical defense compounds in wheat species. However, the contribution and role of phenolic compounds in ancient and modern wheat genotypes for plant-to-plant interference are equivocal. Biological screening of seven wheat genotypes including five emmer wheat genotypes of Triticum turgidum ssp. dicoccum (Zarneh, Singerd, Shahrekord, Khoygan and Joneghan), one modern hexaploid wheat genotype (Triticum aestivum var. Roushan) and one modern tetraploid wheat genotype (Triticum turgidum var. Yavaroos) demonstrated that all wheat genotypes suppressed the seedling growth of Raphanus sativus L. by shoot aqueous extract in a dose–response bioassay. Modern hexaploid wheat genotypes along with ancient tetraploid emmer wheat genotypes possessed a high allelopathic capability. High-performance liquid chromatography diode array detection analysis of aqueous extracts indicated that the ability to synthesise polyphenolic compounds is different among genotypes. The total amount of polyphenolics and flavonoid compounds in shoot aqueous showed a significant correlation to the R. sativus growth suppression. These results suggest that the number of polyphenolics in general and syringic acid in particular may have contributed to the allelopathic effects of ancient tetraploid and modern hexaploid wheat genotypes. At the same time, results showed that ancient tetraploid emmer wheat may offer promising values for their unique composition of allelochemicals, indicating their potential in sustainable crop production systems.