No abstract

As a biostimulant, amino acids play crucial roles in enhancing plant growth and development. These roles, combined with the ability to be approved for organic usage, make amino acids a good choice for sustainable farming systems. This work investigates the effect of onion seed priming with different exogenous amino acids, specifically the impact of seed priming in enhancing a diverse range of morpho-physiological responses of onion seedlings. Here, we primed onion seeds (Cultivar Giza 6) with ten exogenous amino acids. Based on the growth parameters of onion seedlings, data showed that glutamine significantly improved the most studied parameters. Germination percentage (GP) ranged from 85% in Methionine (Met) to 98.5% in Proline (Pro) and Tryptophan (Try), with 10% over the control treatment. Glutamine (Glu) enhanced the vigor index (VI) of onion, giving the seeds a high ability to produce normal seedlings. The most extended root system (≥3.3 cm) was obtained from Glu, Glycine (Gly), Pro, and Try treatments. The maximum shoot length was obtained from treatments (Glu and Try) with more than 60% over control. Priming onion seeds with amino acids (AAs) increased chlorophyll contents compared with non-primed seeds. Glutamine and Threonine (Thr) had the highest results (122 and 127 μg/g fresh weight, respectively), while the Glu treatment registered the highest Carotene contents with 50% over the control treatment. Furthermore, the data illustrate that the principal component analysis-1 (PCA1) indicates 67.2% variability, and PCA2 indicates 14.8% variability. Strong positive correlations were observed between germination percentage, root length, shoot length, dry matter, chlorophyll a, and carotene. The study concluded that the primed onion seeds by glutamine, proline, and tryptophan had the best germination rates.

Canada thistle (Cirsium arvense L.) growing in spring wheat (Triticum aestivum) is difficult to control for several reasons. First, it is a perennial weed that has an extensive root system. Second, the cash‐crop wheat prevents the use of many chemicals, and third, Canada thistle is becoming resistant to many single action herbicides. The objective of this study was to evaluate the effect of postemergence herbicide applications on Canada thistle control growing in a spring wheat field. Replicated studies conducted in Russia between 2015 and 2017 evaluated the impact of different herbicide mixtures on Canada thistle control. The formulated mixtures of (iodosulfuron/mesosulfuron/antidote mefenpyr‐diethyl) mixed with triasulfuron and metsulfuron and triasulfuron + metsulfuron increased wheat yields 48 to 60% and provided the greatest (>85%) Canada thistle suppression in all experiments. Generally, (aminopyralid/florasulam), triasulfuron and (2,4‐D/florasulam) provided little control. It can be concluded that in all treatments, the herbicide mixtures did not provide 100% control, and therefore care must be used to prevent the creation of herbicide resistant Canada thistle. Core Ideas Formulated mixtures of herbicides containing (iodosulfuron/mesosulfuron/antidote mefenpyr‐diethyl) and triasulfuron plus metsulfuron provided the most effective Canada thistle suppression. Canada thistle was better controlled at the early stage of spring wheat. Herbicide mixtures containing multiple modes of action was more effective than a single mode of action herbicide in the control of Canada thistle in wheat.

No abstract

Purple nut sedge (Cyperus rotundus L.) is a problematic weed in plasticulture tomato (Solanum lycopersicum L.) production in Iran as it is difficult to control due to its ability to penetrate plastic mulch. Field trials were carried out at the experimental area of the state farm Safadasht, Shahriar region, Iran, over the fall of 2015 and spring of 2016 to investigate PRE-and POST herbicide programs (PRE transplanting, POST transplanting, and combination of PRE-and POST transplanting) to control purple nut sedge in plasticulture tomato production. PRE herbicide treatment metribuzin and (S)-metolachlor were not effective when applied alone, and did not reduce purple nut sedge plants compared to the weedy control. POST transplanting application of halosulfuron did not significantly affect purple nut sedge plants at 12 wk after application (WAA) in the fall 2015, but treatment favorably reduced density of purple nut sedge at 16 WAA in both seasons. PRE transplanting application of metribuzin or (S)-metolachlor plus POST halosulfuron exerted the greatest control, and purple nut sedge numbers were eventually diminished in both seasons. Experimental treatments did not negatively affect tomato height and yields. Based on our findings, multiple PRE and POST herbicide programs were effective in greater purple nut sedge suppression compared to the lone application of PRE and POST herbicides. The herbicides were selected due to routine use by tomato producers in the area. Using active ingredients from the various herbicide families with different modes of action could facilitate effective management of herbicide-resistant purple nut sedge in tomato fields.