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Foxtail millet (Setaria italica L.) is cultivated around the world for human and animal consumption. There is no suitable herbicide available for weed control in foxtail millet fields during the post-emergence stage. In this study, we investigated the effect and safety of the post-emergence herbicide tribenuron-methyl (TBM) on foxtail millet in terms of grain yield and quality using a split-plot field design. Field experiments were conducted using two varieties in 2013 and 2014, i.e., high-yielding hybrid Zhangzagu 10 and high-quality conventional Jingu 21. TBM treatments at 11.25 to 90 g ai ha(-1) reduced root and shoot biomass and grain yield to varying degrees. In each of the two years, grain yield declined by 50.2% in Zhangzagu 10 with a herbicide dosage of 45 g ai ha(-1) and by 45.2% in Jingu 21 with a herbicide dosage of 22.5 g ai ha(-1) (recommended dosage). Yield reduction was due to lower grains per panicle, 1000-grain weight, panicle length, and panicle diameter. Grain yield was positively correlated with grains per panicle and 1000-grain weight, but not with panicles ha(-1). With respect to grain protein content at 22.5 g ai ha(-1,) Zhangzagu 10 was similar to the control, whereas Jingu 21 was markedly lower. An increase in TBM dosage led to a decrease in grain Mn, Cu, Fe, and Zn concentrations. In conclusion, the recommended dosage of TBM was relatively safe for Zhangzagu 10, but not for Jingu 21. Additionally, the hybrid variety Zhangzagu 10 had a greater tolerance to TBM than the conventional variety Jingu 21.

Foxtail millet planting has a long history and profound role in agricultural civilization. However, weeds have become one of the obstacles restricting the development of the foxtail millet industry. Penoxsulam, as an early post-emergence herbicide for controlling gramineous weeds in paddy fields, is effective for some broadleaf weeds. In this study, six different doses (CK, 0.5X, 1X, 2X, 3X, 4X) of penoxsulam were sprayed at the 3–5 leaf stage of the conventional variety Jingu 21 to study its effect on the growth and development of foxtail millet, in order to screen out the appropriate spraying concentration. The main results are as follows: Within 15 days after spraying penoxsulam, the plant height and leaf area of foxtail millet decreased with the increase in spraying dose, and gradually recovered 15–25 days after spraying, but there were still significant differences compared with CK. The photosynthetic pigment content, net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs), the maximum photochemical efficiency (Fv/Fm), photosynthetic system II actual photochemical efficiency (Y(II)), and photochemical quenching coefficient (qP) of foxtail millet decreased with an increase in the penoxsulam spraying dose, while the intercellular CO2 concentration (Ci) and non-photochemical quenching coefficient (NPQ) showed an upward trend. There was almost no significant difference in each index between the spraying dose of 0.5X and 1X and CK, but the photosynthesis of foxtail millet leaves was still significantly inhibited under a spraying dose of 3X and 4X. Penoxsulam had certain growth-inhibiting effects on Echinochloa crus-galli (L.) Beauv. (E. crus-galli), Digitaria sanguinalis (L.) Scop. (D. sanguinalis), Chenopodium album L. (C. album), and Amaranthus retroflexus L. (A. retroflexus) which increased as the spraying dosage increased. Our study found that spraying dose groups of 0.5X and 1X penoxsulam were safe for foxtail millet growth and could be used to control gramineous weeds in fields. Other spraying doses are not recommended in the field due to their serious phytotoxicity to foxtail millet, which provides a new measure for weed control in foxtail millet fields. [ABSTRACT FROM AUTHOR]

Foxtail millet (Setaria italica L.) is an important crop grown worldwide as a food and fodder crop owing to its potential nutritional and feed values. High-efficiency herbicide varieties is crucial to achieving efficient weeding and ensuring successful foxtail millet production. Herbicides affect several morphological and physiological indicators of foxtail millet. In this study we aimed to evaluate the damage caused by herbicides, improve their effectiveness, and select indicators that accurately reflect herbicide resistance in foxtail millet. Jingu 21, which has the largest planting area in Shanxi province and even the whole of China, is selected as the experimental material to be sown in the field in 2022. A total of 31 herbicides were applied, and 21 traits, including morphological, physiological, and yield-component traits, were measured to assess millet resistance. Principal component analysis was employed to transform these 21 conventional traits into seven independent and comprehensive indexes. These indexes were screened using regression analysis, resulting in the selection of the following indicators: the surface area of the second leaf from the top, peroxidase activity, catalase activity, malondialdehyde content, chlorophyll (a + b), grain weight per ear, and yield. Through membership function and cluster analyses, the resistance of Jingu 21 to 31 herbicides was divided into five categories: extremely weakly resistant, weakly resistant, moderately resistant, strongly resistant, and extremely strongly resistant. Jingu 21 exhibited extremely strong resistance to lactofen, butachlor, and anilofos. After an investigation into the effectiveness of herbicides, it was found that eight herbicides had good effects. [ABSTRACT FROM AUTHOR]

Foxtail millet (Setaria Italica L.) plays a principal role in food security in Africa and Asia, but it is sensitive to a variety of herbicides. This study was performed to clarify whether pyrazosulfuron-methyl can be used in foxtail millet fields and the effect of pyrazosulfuron-methyl on the photosynthetic performance of foxtail millet. Two foxtail millet varieties (Jingu 21 and Zhangzagu 10) were subjected to five doses (0, 15, 30, 60, and 120 g ai ha−1) of pyrazosulfuron-methyl in pot and field experiments. The plant height, leaf area, stem diameter, photosynthetic pigment contents, gas exchange parameters, chlorophyll fluorescence parameters, antioxidant enzyme activities, and antioxidant contents at 7 and 15 days after pyrazosulfuron-methyl application, and the yield of foxtail millet were measured. The results suggested that pyrazosulfuron-methyl inhibited the growth of foxtail millet and reduced the photosynthetic pigment contents, photosynthetic rate, and photosynthetic system II activity. Similarly, pyrazosulfuron-methyl decreased the antioxidant enzyme activities and antioxidant contents. These results also indicated that the toxicity of pyrazosulfuron-methyl to foxtail millet was decreased gradually with the extension of time after application; however, the foxtail millet yield was still significantly reduced. Therefore, pyrazosulfuron-methyl is not recommended for application in foxtail millet fields. [ABSTRACT FROM AUTHOR]

Aims: The incidence of herbicide-resistant blackgrass is escalating in wheat fields; the development of alternatives to traditional herbicides is crucial. Allelopathic wheat can suppress blackgrass. Herein, we investigated the influence of allelopathic wheat on herbicide-resistant blackgrass. Methods: Mesosulfuron-methyl-resistant and -susceptible blackgrass were used. We examined i) root interactions between allelopathic wheat and both blackgrass biotypes, ii) allelochemical 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) production by allelopathic wheat in a root segregation experiment, and iii) responses of allelopathic wheat to root exudates. Signal chemicals in the root exudates of both blackgrass biotypes were characterised. Results: Allelopathic wheat inhibited the growth of roots more than shoots for resistant and susceptible blackgrass. Allelopathic wheat inhibited roots of resistant blackgrass more than those of susceptible blackgrass. Allelopathic wheat significantly shaped blackgrass root behaviour. Resistant blackgrass caused a lower relative increase in DIMBOA production by allelopathic wheat. Root segregation with 30 μm nylon led to greater growth inhibition of blackgrass and a relative increase in allelochemical DIMBOA. Root exudates from blackgrass induced DIMBOA production, but more so for susceptible blackgrass. The concentration of (−)-loliolide, a potential signal chemical, was much lower in the root exudates from resistant than susceptible blackgrass. Conclusions: Allelopathic wheat can interfere with the growth of mesosulfuron-methyl-resistant blackgrass through allelochemical-mediated root interactions. Such allelopathic interference can provide insight into weed management. [ABSTRACT FROM AUTHOR]

Radix Isatidis (Isatis indigotica Fort.) is one of the most important traditional Chinese medicine plants. However, there is no suitable herbicide used for weed control in Radix Isatidis field during postemergence stage. To explore the safety of sulfonylurea herbicide nicosulfuron on Radix Isatidis (Isatis indigotica Fort.) seedlings and the photosynthetic physiological response of the plant to the herbicide, biological mass, leaf area, photosynthetic pigment content, photosynthetic rate, chlorophyll fluorescence characteristics, and P700 parameters of Radix Isatidis seedlings were analyzed 10 d after nicosulfuron treatment at 5th leaf stage in this greenhouse research. The results showed that biological mass, total chlorophyll, chlorophyll a, and carotenoids content, photosynthetic rate, stomatal conductance, PS II maximum quantum yield, PS II effective quantum yield, PS II electron transport rate, photochemical quenching, maximal P700 change, photochemical quantum yield of PS I, and PS I electron transport rate decreased with increasing herbicide concentrations, whereas initial fluorescence, quantum yield of non-regulated energy dissipation in PS II and quantum yield of non-photochemical energy dissipation due to acceptor side limitation in PS I increased. It suggests that nicosulfuron ≥1 mg L−1 causes the damage of chloroplast, PS II and PS I structure. Electron transport limitations in PS I receptor side, and blocked dark reaction process may be the main cause of the significantly inhibited growth and decreased photosynthetic rate of Radix Isatidis seedlings. [ABSTRACT FROM AUTHOR]