Tembotrione- a post-emergence herbicide for control of diverse weed flora in maize (Zea mays L.) in North-West India

Atrazine was the primary tool available for the control of weeds in maize. Being a pre-emergence, it provides effectivecontrol of some of the annual grasses and broadleaf weeds, but for complex weed flora, maize crop needssome post-emergence herbicide. The efficacy of tembotrione for post-emergence weed control in maize wasevaluated in a field study carried out during summer seasons in 2009, 2010 and 2011 and at farmers’ field in 2012.Tembotrione was applied at 100, 110 and 120 g a.i ha-1 along with 1000 ml ha-1 surfactant as post-emergence(20 days after sowing), atrazine 1000 g a.i ha-1 (standard) as PRE, weed free and unsprayed control were keptfor comparison. Tembotrione at 110 and 120 g ha-1 applied with surfactant 1000 ml ha-1 at 20 days after sowing,significantly reduced density and biomass of grasses and broadleaf weeds as compared to its lower dose of 100g ha-1, atrazine, and unsprayed control. Tembotrione showed reduced efficacy on *. POST application of tembotrione110-120 g ha-1 along with surfactant attained higher grain yields (7.33-7.40 t ha-1) than atrazine 1000 g ha-1,tembotrione 100 g ha-1 and unsprayed control and were at par with a weed-free chec

Editorial: Integrated weed management for reduced weed infestations in sustainable cropping systems

International audienceWeeds are a major biotic constraint of agricultural systems worldwide interfering with crop production and resource use efficiency (Oerke, 2006; Colbach et al., 2020). Chemical control is a cost-and time-effective weed management method and for that reason remains as the most widely and frequently used method to sustain agricultural productivity and food security in the current era. However, repeated use of a limited number of herbicide active ingredients in non-diversified crop rotations enhances the selection of herbicide-resistant weed biotypes. The over-reliance on chemical weed control has led to shifts in weed communities (Mahaut et al., 2019) which are now becoming dominated by highly competitive and herbicide-resistant prone species able to cause significant yield losses (Adeux et al., 2019b). Widespread herbicide resistance (Heap, 2023) accompanied by the increasing concern of herbicides entering the food chain and/or impacting the environment has created a tremendous demand for alternative weed management methods. Alternative weed management practices that reduce weed populations indirectly lowers selection pressure thus helping delay the evolution of further herbicide resistance. Controlling weeds during the critical period of weed removal is paramount for achieving the full yield potential of any crop (Zimdahl, 1988; Colbach et al., 2020). In conservation tillage with cover cropping, research on the critical period of weed removal is warranted to further elucidate cover crop weed suppressive attributes and efficient utilization of herbicides (Kumari et al.). Preventive weed control measures include all the possible means that restrict the entry and establishment of weeds in an area. Cultural control is an ecological method of weed control in which good crop management methods are followed to stimulate rapid crop growth and canopy closure (Petit et al., 2018). Cultivar selection, Frontiers in Agronomy frontiersin.org 0

Recent Advances in Green Synthesis of Ag NPs for Extenuating Antimicrobial Resistance

Combating antimicrobial resistance (AMR) is an on-going global grand challenge, as recognized by several UN Sustainable Development Goals. Silver nanoparticles (Ag NPs) are well-known for their efficacy against antimicrobial resistance, and a plethora of green synthetic methodologies now exist in the literature. Herein, this review evaluates recent advances in biological approaches for Ag NPs, and their antimicrobial potential of Ag NPs with mechanisms of action are explored deeply. Moreover, short and long-term potential toxic effects of Ag NPs on animals, the environment, and human health are briefly discussed. Finally, we also provide a summary of the current state of the research and future challenges on a biologically mediated Ag-nanostructures-based effective platform for alleviating AMR

Decision Support Systems for Weed Management

Editors: Guillermo R. Chantre, José L. González-Andújar.Weed management Decision Support Systems (DSS) are increasingly important computer-based tools for modern agriculture. Nowadays, extensive agriculture has become highly dependent on external inputs and both economic costs, as well the negative environmental impact of agricultural activities, demands knowledge-based technology for the optimization and protection of non-renewable resources. In this context, weed management strategies should aim to maximize economic profit by preserving and enhancing agricultural systems. Although previous contributions focusing on weed biology and weed management provide valuable insight on many aspects of weed species ecology and practical guides for weed control, no attempts have been made to highlight the forthcoming importance of DSS in weed management. This book is a first attempt to integrate 'concepts and practice' providing a novel guide to the state-of-art of DSS and the future prospects which hopefully would be of interest to higher-level students, academics and professionals in related areas

Cellulose content variation and underlying gene families in bread wheat

Synthesis and remodelling of various cell wall components play a vital role in plant development, architecture and innate immunity. Plant cell walls are mainly composed of cellulose and hemicellulose which produce a bulk of renewable biomass vital for food, feed and biofuels. Cellulose in the primary and secondary cell wall of plants is synthesised by the family of genes called CesA (Cellulose synthase A). This study is a first report about the distinctive structural and functional motifs of primary and secondary cell wall synthesis genes. Using publicly available genomic databases and resources, 22 TaCesA genes located on A, B and D genomes of hexaploid wheat were identified. Cellulose in secondary cell walls is synthesised by three genes (TaCesA4, TaCesA7, and TaCesA8) co-expressing in the mature stem tissues of bread wheat. But the relative transcript abundance was found to be higher for TaCesA4 genes, which indicates its major role in the secondary cell wall cellulose synthesis. We employed the virus-induced gene silencing (VIGS) approach to functionally characterize TaCesA4 gene through silencing its three homoeologs (TaCesA4A, TaCesA4B, and TaCesA4D) collectively in bread wheat. Silenced plants showed a significant reduction in transcript abundance and cellulose content in the stem tissues. However, the anatomy of stem cross sections of silenced plants did not show any evidence of abrupt changes in the secondary cell wall of stems at the booting stage. A panel of 265 diverse wheat lines was evaluated for natural variation of cellulose content that was linked to the SNP genotyping data through genome-wide association studies (GWAS). This analysis led the identification of novel genes (β-tubulin and UDP-glycosyl transferase) associated with cellulose biosynthesis in wheat. In addition, Cellulose synthase-like (Csl) genes of wheat were explored. These genes have been known for the regulation/synthesis of hemicelluloses such as heteromannan, xyloglucan, heteroxylans, and mixed-linkage glucan. A total of 108 Csl genes were identified based on the family specific Pfam conserved domains. Tissue-specific expression and phylogeny of Csl genes were also elucidated. Taken together, genome- wide exploration of CesA & Csl genes and their association with cellulose and hemicellulose biosynthesis offer a valuable resource for designing high yielding wheat varieties possessing appropriate lignocellulosic traits.La synthèse et la remodelage des divers composants des parois cellulaires jouent un rôle important dans le développement, l'architecture et l'immunité innée des plantes. Les parois cellulaires sont principalement composées de cellulose et d'hémicellulose, lesquelles représentent une quantité importante de biomasse dans les aliments pour humains et bétail autant que dans les biocombustibles. La cellulose présente dans les parois cellulaires primaires et secondaires est synthétisée par des gènes de la famille CesA (Cellulose synthase A). Cette étude est la première à décrire les motifs structurels et fonctionnels caractéristiques de ces gènes de synthèse de parois cellulaires primaires et secondaires. Utilisant des ressources génétiques disponibles, 22 gènes TaCesA situés sur les génomes A, B et D du blé hexaploïde furent identifiés. La cellulose dans les parois cellulaires secondaires est synthétisée par trois gènes (TaCesA4, TaCesA7 et TaCesA8) qui sont coexprimés dans les tissus matures des tiges de blé. Cependant, les transcrits du gène TaCesA4 étaient plus abondants, ce qui indique l'importance élevée de ce gène pour la synthèse de la cellulose dans les parois cellulaires secondaires. Par biais d'une technique silençage de gène induit par virus (VIGS), nous avons caractérisé la fonctionnalité du gène TaCesA4 en désactivant tous ses trois homologues (TaCesA4A, TaCesA4B et TaCesA4D) dans le blé. Les plantes avec les gènes ainsi désactivés montrèrent une réduction significative en abondance des transcrits et en quantité de cellulose présente dans les tissus de leurs tiges. Cependant, l'anatomie des sections transversales des plantes aux gènes désactivés ne montrèrent aucune évidence de changements dramatiques dans les parois secondaires des cellules des tiges au phase de reproduction. Un ensemble de 265 diverses lignées de blé fut évalué pour caractériser la variation naturelle de la teneur en cellulose. Ces différences furent ensuite comparées avec des données de génotypage de polymorphismes mononucléotidiques par biais d'une étude d'association pangénomique. Cette analyse mena à l'identification de nouveaux gènes (β-tubulin et glycosyl transférase UDP) associés avec la biosynthèse de la cellulose dans le blé. Des gènes du blé similaires à ceux de la cellulose, Cellulose synthase-like (Csl), furent aussi explorés. Ceux-ci ont déjà été reconnus pour leur rôle dans la régulation et la synthèse des hémicelluloses tels que le l'hétéromannane, le xyloglucane, les hétéroxylanes, et les glucanes à liaisons mixtes. Un total de 108 gènes de Csl fut identifié grâce aux domaines Pfam conservés spécifiques à cette famille, et la phylogénie et l'expression au niveau des tissus de ceux-ci furent ensuit analysées. L'analyse en profondeur de l'architecture génétique de la biosynthèse de la cellulose et de l'hémicellulose offre un atout précieux pour l'amélioration végétale et les modifications génétiques des variétés de blé en but d'obtenir une production de biomasse désirable tout en conservant une résistance suffisante envers de divers stresses

Understanding crop-weed-fertilizer-water interactions and their implications for weed management in agricultural systems

Crops and weeds share the same aboveground/aerial (sunlight, space, atmospheric gases, etc.) and underground/soil (water and nutrients) resources. Competition is a predictable response of organisms living in communities, and is a struggle between two organisms for a limited resource that is essential for their growth. Crop-weed competition causes an alteration in the utilization of various resources and also affects complex interactions between plants and environmental factors. Water, nutrients, light, and space are the major factors for which organisms compete. Light and space are the main aboveground resources, and the effects of competition for these resources can be visually observed. This article focusses on crop-weed interactions for underground resources - nutrients and water. Weeds, being more aggressive, adaptive and persistent than crops, pose a serious threat to crop production as they have the ability to survive under adverse conditions and extract more water and nutrients from the soil; thereby, reducing crop yields. Fertilizer application and inherent soil fertility have a definite influence on weed diversity, emergence, growth, dormancy, persistence, and crop-weed competition. Weed suppression with balanced fertilization through increased competition for light has been regarded as one of the most important determinants of the yield advantage of a crop, and the effect on yield depends upon the interaction of crop and weed flora. The elimination of weeds from crops is the most efficient and practical means of reducing transpiration and thus saving water for crop use. Additional fertilizer and water amounts cannot compensate fully for yield losses due to weed competition, but appropriate fertilizer and water management could be used as an important tool in integrated weed management systems, which may prove helpful for achieving higher net returns

Weed control in conventional soybean with pendimethalin followed by imazethapyr plus imazamox/quizalofop

The objectives of this study were to evaluate the efficacy of pendimethalin applied pre-emergence (PRE) followed by (fb) post-emergence (POST) application of imazethapyr plus imazamox/quizalofop for weed control and their effect on conventional soybean injury, yield attributes, and yield. Field experiments were conducted in 2013 and 2014 in conventional soybean. Herbicide treatments provided ≥ 90, 70, and 85% control of crowfoot grass, large crabgrass, and goosegrass, respectively, and ≤ 80% control of false amaranth and horse purslane at 30 d after sowing (DAS). At 60 DAS, pendimethalin applied alone or fb hand-hoeing/quizalofop/imazethapyr plus imazamox provided 100% control of goosegrass and 65 to 100% control of crowfoot grass/large crabgrass. Pendimethalin fb imazethapyr plus imazamox/quizalofop as well as quizalofop applied alone resulted in complete control of crowfoot grass, large crabgrass, and goosegrass, but control of broadleaf weeds was variable. Pendimethalin fb imazethapyr plus imazamox at 70 g ha─1 at 28 DAS, imazethapyr plus imazamox at 60 or 70 g ha─1 at 21 DAS fb quizalofop at 37.5 g ha─1 at 42 DAS resulted in soybean branch numbers per plant, number of pods per plant, and soybean seed yield comparable to weed-free control. Control of Benghal dayflower and purple nutsedge was not acceptable.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

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Novel Structural and Functional Motifs in cellulose synthase (CesA) Genes of Bread Wheat (Triticum aestivum, L.).

Cellulose is the primary determinant of mechanical strength in plant tissues. Late-season lodging is inversely related to the amount of cellulose in a unit length of the stem. Wheat is the most widely grown of all the crops globally, yet information on its CesA gene family is limited. We have identified 22 CesA genes from bread wheat, which include homoeologs from each of the three genomes, and named them as TaCesAXA, TaCesAXB or TaCesAXD, where X denotes the gene number and the last suffix stands for the respective genome. Sequence analyses of the CESA proteins from wheat and their orthologs from barley, maize, rice, and several dicot species (Arabidopsis, beet, cotton, poplar, potato, rose gum and soybean) revealed motifs unique to monocots (Poales) or dicots. Novel structural motifs CQIC and SVICEXWFA were identified, which distinguished the CESAs involved in the formation of primary and secondary cell wall (PCW and SCW) in all the species. We also identified several new motifs specific to monocots or dicots. The conserved motifs identified in this study possibly play functional roles specific to PCW or SCW formation. The new insights from this study advance our knowledge about the structure, function and evolution of the CesA family in plants in general and wheat in particular. This information will be useful in improving culm strength to reduce lodging or alter wall composition to improve biofuel production