Allelopathic trade-offs of rye and wheat residues versus 2-benzoxazolinone: Impacts on cotton growth

Authors: LI, YUE - Texas Tech University; ALLEN, VIVIEN - Texas Tech University; Chen, Junping; WESTER, DAVID - Texas A&M University

Submitted to: Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/24/2025
Publication Date: 9/25/2025
Citation: Li, Y., Allen, V.G., Chen, J., Wester, D.B. 2025. Allelopathic trade-offs of rye and wheat residues versus 2-benzoxazolinone: Impacts on cotton growth. Biology. 14(10). https://doi.org/10.3390/biology14101321.
DOI: https://doi.org/10.3390/biology14101321

Interpretive Summary: Cover crops provide many benefits for soil health including reducing soil erosion. However, the allelopathic effects of small grain cover crops on the growth and development of subsequent crops remain a concern. In this study, we have found the wheat and rye residues and their allelopathic chemicals in the soil negatively affecting germination, early growth and leaf chlorophyll content of cotton plants. The degree and duration of such effect are correlated with the amounts of residues in soil, as well as soil moisture contents and soil types. The findings provide crucial information to design effective strategies for optimizing cereal–cotton rotations within sustainable agricultural systems.

Technical Abstract: Cover crops provide important benefits for soil conservation, yet their allelopathic effects on subsequent cash crops remain a concern. This study aimed to clarify the impact of rye and wheat residues and the purified allelochemical benzoxazolinone (BOA) on cotton germination and early growth under greenhouse conditions. Four experiments were con-ducted using varying residue rates and BOA concentrations to compare short, intermedi-ate, and long-term effects. Results showed that cotton suppression was dose-dependent, with rye exerting the strongest and most persistent inhibition, wheat having intermediate effects, and BOA alone showing weaker and trait-specific effects. Although BOA and re-lated benzoxazinoids degraded rapidly in soil, inhibitory effects of rye residues persisted for up to 364 days, likely due to degradation products or synergistic interactions. At mod-erate rye biomass, a hormetic stimulation of seedling growth was observed, whereas ex-cessive biomass consistently suppressed establishment. These findings indicate that bio-mass level is a critical determinant of allelopathic intensity and that management strate-gies such as grazing or partial residue removal may mitigate risks. Overall, the study highlights that understanding benzoxazinoid-mediated allelopathy is essential for opti-mizing cereal–cotton rotations within sustainable agricultural systems.