Physiological and anatomical modifications of exotic weed (goat grass), wheat and Egyptian grassy weeds (wild oat and canary grass) under chemical weed control condition

<title>Abstract</title> <p> Goat grass is a potential weed risk associated with the introduction of a new plant species into Egypt. Therefore, the aim of this study is to conduct a comparative evaluation of the Physiological and anatomical responses of goat grass as an exotic weeds and wild oat and canary grass as local weeds in Egypt, to the effects of ten treatments, namely: untreated check (T ₁ ); Axial 5% EC (T ₂ ); Broadway star 8.5% WG (T ₃ ); Traxos 5% EC (T ₄ ); Spin top 10% EC (T ₅ ); Santo 17.5% EC (T ₆ ); Fakto 36% EC (T ₇ ); Future 7.5% EW (T ₈ ); Hock 15% WP (T ₉ ); Atlantis 1.2% OD (T ₁₀ ), on pigment content in leaves and the cross-section of roots. Two field experiments were carried out at the wire house of the Weed Research Central Laboratory, Egypt, during the 2023/24 and 2024/25 winter seasons under artificial infestation by the weed species, cultivated with the wheat variety Beni Suef 5.The results showed that the anatomical modification of the root cross-section was greater in wild oat than in goat grass. Total chlorophyll content was significantly reduced in the local wild oat by most herbicides, while only a few herbicides significantly decreased it in goat grass. From these results, it is clear that wild oat, as a local weed, is most sensitive followed by canary grass, whereas goat grass showed less responsiveness to the applied herbicides. Notably, T4, T ₆ , T ₈ and T ₁₀ significantly reduced total chlorophyll (a + b) and the cross section size of goat grass root and may be useful for controlling this weed. </p>