One of the main abiotic factors affecting agricultural productivity in semi-arid regions is salinity. Seed priming is a frequently used method to enhance plant growth under saline environments. The aim of this work was to demonstrate the differences in eight agronomical characteristics of two grass pea varieties under two salinity regimes (80 and 160 mM NaCl) when pre-exposed to seed priming (hydropriming, biopriming with Bacillus subtilis and their combination). The two varieties responded well to the priming treatments, with more beneficial effects monitored for the local variety. Evaluating the root characteristics that are most affected by stress, it was found that, at 80 mM NaCl, the combination of biopriming and hydropriming increased the fresh root weight by 36.8% and root length by 70% in the commercial variety, and by 124% and 47%, in the local variety, respectively. At 160 mM NaCl, biopriming increased the fresh root weight by 40.3% and root length by 50.3% in the commercial variety, while in the local variety, the combination of biopriming and hydropriming increased the fresh root weight by 124% and root length by 47%, respectively. Overall, biopriming and the combination of biopriming and hydropriming significantly enhanced plant growth characteristics of the two grass pea genotypes.

Agricultural practices must adapt to address new climatic conditions and the rising global demand for food. Among these practices, cultivating crops resilient to various stresses while maintaining productivity—such as annual legume crops—is essential. This study aims to assess the competitive interactions between legume crops and weeds. Field experiments were conducted using a Randomized Complete Block design with three replicates. Six weed treatments, representing the presence and absence of weeds (utilizing natural weed communities) were applied as the main plots for each of three-grain legumes: pea (Pisum sativum), faba bean (Vicia faba), and vetch (Vicia sativa), under semi-arid Mediterranean conditions. To evaluate the crops' competitive abilities, weed and crop biomass were collected at 3, 6, and 9 weeks after sowing (WAS). Additionally, pod yield was measured for each species to determine crop yield. The results indicated that faba bean exhibited the strongest growth competition, sowing: a) the smallest difference in final (9WAS) biomass between weedy and weed-free treatments compared to peas and vetch (30, 55, 57% reduction, respectively), and b) significant benefits in continuous removal of weeds in peas, vetch as compared to the no-benefits in such treatment in faba beans. In terms of yield tolerance to weed competition, peas demonstrated the greatest resilience, followed by faba beans and vetch (24, 38, 76% reduction, respectively). The timing of the manifestation of the crops' suppressive abilities varied: in peas and vetch, there was no measurable effect on growth due to the weed competition at the early and medium stages (at 3 and 6WAS) of crop development but only at the late stage (9WAS). Given the importance of grain legumes and the limited research on their competitive interactions with weeds, further studies are needed to promote more sustainable agricultural practices.

Broomrapes (Orobanche and Phelipanche spp.) are parasitic weeds that significantly impact the productivity of major crops in the Mediterranean region, like tomato (Solanum spp.) and faba bean (Vicia faba) species. This review article extensively discusses management strategies to control broomrapes, which range from preventive measures to curative approaches. Additionally, it includes meaningful information on the intricate molecular mechanisms underlying the broomrape–host interaction, focusing on the host recognition of parasitic plant molecular patterns and the hormonal crosstalk that regulates the establishment of parasitism. Moreover, this article highlights the potential of breeding for resistance in cultivated crops, such as tomato and faba bean, as a sustainable, long-term solution to combat broomrape infestation. This review serves as a valuable resource for both researchers and farmers, offering insights for developing, implementing, and adapting effective and environmentally sustainable management practices for broomrape in Mediterranean agricultural systems.

Tomato (Solanum lycopersicum) is a major horticultural crop of high economic importance. Phelipanche and Orobanche genera (broomrapes) are parasitic weeds, constituting biotic stressors that impact tomato production. Developing varieties with tolerance to broomrapes has become imperative for sustainable agriculture. Solanum pennellii, a wild relative of cultivated tomato, has been utilized as breeding material for S. lycopersicum. In the present study, it is the first time that an in-depth analysis has been conducted for these two specific introgression lines (ILs), IL6-2 and IL6-3 (S. lycopersicum X S. pennellii), which were employed to identify genes and metabolic pathways associated with resistance against broomrape. Comparative transcriptomic analysis revealed a multitude of differentially expressed genes (DEGs) in roots, especially in the resistant genotype IL6-3, several of which were validated by quantitative PCR. DEG and pathway enrichment analysis (PEA) revealed diverse molecular mechanisms that can potentially be implicated in the host’s defense response and the establishment of resistance. The identified DEGs were mostly up-regulated in response to broomrape parasitism and play crucial roles in various processes different from strigolactone regulation. Our findings indicate that, in addition to the essential role of strigolactone metabolism, multiple cellular processes may be involved in the tomato’s response to broomrapes. The insights gained from this study will enhance our understanding and facilitate molecular breeding methods regarding broomrape parasitism. Moreover, they will assist in developing sustainable strategies and providing alternative solutions for weed management in tomatoes and other agronomically important crops.

Gaining a comprehensive understanding of how weed communities respond to both environmental and human-induced factors is of paramount importance in developing effective and ecologically sound weed control strategies. The objectives of the current research were to (1) assess the effect of the main weed management practices used in Greek olive groves on weed species’ diversity; (2) explore the filtering effect of management, site, and soil variables in determining weed species’ composition; and (3) shed light on the association between weed species’ composition and the diversity of the understory vegetation of olive groves. To accomplish these objectives, winter weed species’ coverage was assessed in 116 olive groves, both conventional and organic, distributed across three provinces in southern Greece. The investigation encompassed 29 explanatory variables, categorized into three groups: soil (22), management practices (6), and site conditions (1). It was confirmed that glyphosate use may lower biodiversity and species richness; however, this trend was not universal. In fact, the negative influence of the presence of Oxalis pes-caprae L. on species richness and diversity far outweighed the effect of spraying glyphosate. Redundancy analysis (RDA) revealed that among the 29 variables used to describe the ecological niche, eight (i.e., Mn, Mg, chemical spraying, mowing, rotary tiller, grazing, irrigation, and elevation) were significant and explained 21.5% of the total variation in weed species’ data. Interestingly, the soil Mn concentration was identified as the most influential one, highlighting the importance of soil micronutrients in determining weed species’ composition. The variation partitioning procedure demonstrated that the effect of the management variables on weed species’ composition accounted for 2.2 times the variance of soil variables and 4.5 times the variance of elevation. The present findings might help to enhance optimal management in olive groves that can sustain the biodiversity of flora and, in turn, provide various ecosystem services to agro-ecosystems.

Broomrapes (Orobanche and Phelipanche spp.) are non-achlorophyllous parasitic plants belonging to the Orobanchaceae family, with some species evolving to infest agricultural crops, causing substantial economic losses. This study focuses on Orobanche and Phelipenche species prevalent in Tunisia, particularly Orobanche crenata, Orobanche foetida and Phelipanche ramosa, which pose a significant threat to legume crops and other agronomically important plants. These parasitic species cause severe damage before their aboveground appearance, making early detection and management crucial. Successful breeding programs targeting their hosts necessitate a comprehensive understanding of the genetic variability within different broomrape populations. A plethora of molecular markers, including RAPD, ISSR, AFLP, SSR and SNPs, were employed to evaluate the genetic diversity of Orobanche spp., mainly in Mediterranean countries. This research seeks to analyze the genetic variability and structure of thirty-four (34) Tunisian Orobanche and Phelipanche populations infesting various crops and wild plants. The results demonstrated a higher genetic differentiation within populations rather than between populations and no clear differentiation based on the geographic origins of the populations. By measuring the genetic diversity of a large number of broomrape populations that affect both wild species and crops, this study aims to support efforts toward establishing effective management approaches.

Weed control in corn is a major challenge due to increasing problems with highly dominant weed species and herbicide resistance evolution. Common lambsquarters and johnsongrass constitute up to 80% to 90% of the weed population in many spring crops, such as soybean [Glycine max (L.) Merr.], sunflower (Helianthus annuus L.), and corn, in Serbia. Currently, acetolactate synthase-inhibiting herbicides, such as the systemic selective sulfonylurea nicosulfuron, are most commonly used for chemical weed control of those species. A better understanding of the impact of nozzle type and adjuvant use on nicosulfuron efficacy can help to improve control of common lambsquarters and johnsongrass and minimize herbicide resistance development. Field trials were conducted in Serbia from 2020 to 2022 to evaluate the impact of two adjuvants (a non-ionic surfactant [NIS] and a mineral fertilizer ammonium sulfate [AMS]) and two nozzle types (drift-reducing nozzles and flat-fan nozzles) on common lambsquarters and johnsongrass control using nicosulfuron. Satisfactory biomass reduction of common lambsquarters (83% to 87%) and johnsongrass (83% to 97%) was achieved after nicosulfuron application. Adding a NIS adjuvant increased the biomass reduction for common lambsquarters (94% to 98%) and johnsongrass (90% to 100%) independently of the nozzle type used. Selection of nozzle type did not show consistent effects on common lambsquarters and johnsongrass control. Nicosulfuron efficacy was increased with NIS adjuvant for both nozzle types compared to nicosulfuron solo for both species, and Extended Range (XR) TeeJet((R)) nozzles on average resulted in a higher efficacy for common lambsquarters compared to Turbo TeeJet((R)) induction. Adding a mineral AMS adjuvant resulted in lower biomass reduction for both nozzle types and weed species (65% to 78% and 61% to 91% for common lambsquarters and johnsongrass, respectively). Corn grain yield was predominantly influenced by annual meteorological conditions and adjuvant type added to nicosulfuron. This research suggests that addition of the non-ionic adjuvant is an essential factor for successful control of common lambsquarters and johnsongrass in corn and enables use of drift-reducing nozzles.

Lolium spp. are troublesome weeds mainly found in winter cereal crops worldwide, including Europe. In recent years resistant mechanisms have been evolved to several important herbicides. In this study we investigated the mechanisms responsible for conferring glyphosate resistance in some Lolium spp. populations. A holistic approach was used, based on dose-response experiments, determination of shikimic acid concentration in plant leaf tissue, as well as molecular analyses. More specifically, in three Lolium spp. populations the existence of a mutation in the Pro-106 codon of the 5-enolpyruvylshikimate-3 phosphate synthase (EPSPS) gene was investigated as well as the relative transcript levels of four ABC-transporter genes were monitored at three time points after glyphosate application. The results demonstrated that glyphosate resistance is a multifactor phenomenon. Relative transcript levels of the ABC-transporter genes were abundant at very early time points after glyphosate treatments. Dose-response experiments and shikimate analyses were in accordance with the findings of the quantitative PCR (qPCR) analyses. We suggest that relative expression ratio of ABC-transporter genes can be a useful tool to rapidly identify Lolium spp. populations resistant to glyphosate.

Hairy fleabane (Conyza bonariensis (L.) Cronq.) is an annual weed which occurs typically on waste land and crops such as orchards and vineyards. It is considered one of the worst weeds worldwide, including Greece, because it has developed resistance to glyphosate. Glyphosate is a systemic, non-selective herbicide and it is the world’s biggest selling for weed control. Salicylic acid is a phenolic growth regulator, providing protection against biotic and abiotic stress of plants. In the present study, it is investigated the effect of a synthetic compound which is a chemical analog to salicylic acid (benzo (1,2,3) - thiadiazole −7-carbothioic acid S - methyl ester -BTH), in fleabane resistant and susceptible biotype, on glyphosate resistance. Some plants from resistant and susceptible biotype were sprayed with glyphosate, while others were sprayed with both BTH and glyphosate. The proline content, hydrogen peroxide (H2O2) content and malondialdehyde (MDA) content in fleabane leaves were then determined on the 1st, 6th and 10th days following treatment. The concentration of shikimic acid and photosynthetic activity was determined on the 3rd day after treatment. The results showed that the BTH caused protection against glyphosate damage in both fleabane biotypes, decreasing the hydrogen peroxide and MDA content and increasing the proline content. However, BTH did not affect the concentration of shikimic acid. Moreover, resistant and susceptible biotype were affected differently by BTH application. Considering all the above, we can conclude that BTH induced the defense in plants, in both biotypes, after the glyphosate application. Furthermore, susceptible biotype was affected more by BTH application than resistant biotype. Although, the defense mechanisms in susceptible biotype were induced more profoundly after BTH application compared to resistant biotype, susceptible biotype showed slow activation of defense mechanisms, thus it could not survive possibly due to the fact that glyphosate action had already caused detrimental effects on plants.

The effects of different measures within maize cropping technology, aimed to suppress weeds as a part of integrated weed management (IWM) system, are analysed and evaluated in this manuscript, in line with the results of long-term experiments. For sustainable maize (Zea mays L.) production, implementation of IWM system aiming to reduce reliance on chemical weed control within Europe is a key priority. This IWM system includes all possible solutions, such as preventive, direct, biological, mechanical and alternative measures. A cropping system approach is essential to manage weeds, utilize genetic potential of maize genotypes and reduce yield losses due to weed competition. Long-term experiments are nowadays rare, but they are an excellent and reliable method for comparing cropping systems regarding yield and reduction of weed infestation level. In the research program implemented at the Maize Research Institute Zemun Polje in Central Serbia, the effects of different cropping measures and their interactions as a part of IWMs were studied during ten years. Maize rotations with winter wheat (Triticum aestivum L.) and soybean (Glycine max (L.) Men.), combined with herbicide application, showed the best effect on weed biomass reduction, 92.1% and 92.2%, respectively. Winter wheat was a better preceding crop for maize than soybean, especially in combination with herbicides applied in recommended as well as in half of recommended rate. Intensification of soil tillage significantly reduced maize weed infestation, especially abundance of perennial species: Johnson grass (Sorghum halepense (L.) Pers.), Canada thistle (Cirsium arvense (L.) Scop.) and field bindweed (Convolvulus arvensis L.). Other measures, such as type of fertilizer, maize row space and crop density, cover cropping and intercropping also affected weed biomass production in maize fields. Maize growing with reduced row spacing contributed to weed biomass reduction by 27.4%, while application of slow-release urea contributed to crop competitiveness. Weed biomass in sweet maize (Zea mays L. convar. saccharata) grown with common vetch as a cover crop was significantly reduced (48.5 g m(-2)) compared with the treatment without a cover crop (564.3 g m(-2)).

Faba bean is an important grain legume, grown for human consumption and animal feed and can be used as an alternative to soybean protein. Drought and heat strongly influence faba bean growth and production, especially in flowering and pod development stages. The aim of this study was to determine the response of six cultivars to different environmental conditions during the 2018-2019 growing season. Four inbred lines and two commercial cultivars were sown in different environments in South, Central and North Greece. At each location, a randomized complete block design with four replications was used. Different characteristics such as plant height, number of pods plant-1, number of seeds pod-1, seed yield and 1000-seed weight, were recorded. The results indicated that all traits were significantly affected by different climatic conditions and cultivars. In most cases, seed yield and 1000-seed weight decreased with increasing drought conditions in the southern site. KK10 produced higher yield and pods plant-1, especially in North and Central Greece. The late maturity cultivars, ‘Polycarpe’ and KK14, showed lower values for the seed traits under all locations. Multi-location trials are useful for the evaluation of new cultivars and lead to an increase in production of feedstuff directly available to farmers.

Repeated applications of the same herbicide(s), which are characterized by the same mode of action, increase selection pressure, which in turn favours the evolution of herbicide-resistant weeds. Glufosinate is a broad-spectrum non-selective herbicide being used for weed control for many years around the world. Rigid ryegrass (Lolium rigidum Gaud.) is an economically important grass weed in Greece. Recent complaints by growers about control failure of rigid ryegrass with glufosinate require further investigation and have been the basis of this study. The objectives of this study were to confirm the existence of glufosinate-resistant L. rigidum in Greece and evaluate the effect of L. rigidum growth stage on glufosinate efficacy. Twenty populations of rigid ryegrass from Greece were sampled from five regions, and whole plant dose–response studies were conducted for five populations under controlled conditions with eight rates of glufosinate (0.0, 0.098, 0.187, 0.375, 0.75, 1.5, 3.0, and 6.0 kg a.i. ha−1). Glufosinate resistance was confirmed in three out of five populations with the level of resistance ranging from three-to seven-fold compared with the susceptible populations based on above-ground biomass reduction. Results also revealed that the level of glufosinate-resistance of rigid ryegrass was dependent on the growth stage at which it was applied.

Site-specific weed management presupposes the careful monitoring and mapping of weed infestation areas. Cut-edge sensor technologies coupled with geographical information systems (GIS) provide the means for reliable decision-making concerning weed management even in sub-field level. In present research, two different spectral sensing systems were engaged in order to digitally map weed patches as grown in four different cotton fields in Central Greece. The systems used were a set of two Crop Circle multispectral sensors ACS-430 and a digital camera Nikon D300S. The spaces between cotton rows were scanned and photographed with the two systems accordingly. Raw recorded data were stored and analyzed in GIS environment producing spatially interpolated maps of red-edge normalized difference vegetation index (NDVI) and weed cover percentage values. Both mapping approaches were satisfactorily related to weed distribution as occurred in the fields; however, the photographic method tended to underestimate weed populations. Correlation of red-edge NDVI and weed cover values, at the points where photographs were taken, as revealed by Pearson’s correlation coefficient was high (r > 0.83) and statistically significant at the 0.01 level. A first-degree linear equation adequately modeled (R2 > 0.7) the between value pair relations, strengthening the validity of the two methodologies in spatially monitoring weed patches. The methodologies and the technologies used in the study can be used for yearly mapping weed flora in cotton cultivation and potentially constitute a means of rationalizing herbicide application in terms of doses and spatio-temporal decision-making.

Glyphosate is the most important herbicide globally, and horseweed (Conyza canadensis) has been one of the most commonly encountered weed species that has developed resistance to it in various parts of the world, including Greece. After glyphosate application, horseweed populations show a wide range of phenotypic plasticity in response to selection pressure. In previous work, we have proposed a herbicide resistance mechanism that is not due to a point mutation at the codon 106 of EPSP synthase but most likely due to a synchronized overexpression of EPSPS and the ABC transporter genes. In the current study, it is hypothesized that the observed phenotypic alterations and differential expression of the EPSPS gene could be attributed to epigenetic changes. DNA methylation plays a pivotal role in many biological procedures such as gene expression, differentiation, and cellular proliferation. Sodium bisulfite sequencing was used to detect epigenetic changes that occur at the C5 position of cytosine residues within CpGdi nucleotides in two horseweed populations (resistant vs. susceptible). Results show differential methylation pattern between the two populations. This work will elucidate the naturally increased resistance of C. Canadensis to glyphosate and set the bases for future development of techniques that restrict weed resistance to herbicides.

The effect of nitrogen (N) application rate and sowing date on seed quality and pod production of four cultivars of okra (Abelmoschus esculentus L.) were examined. Seeds of four okra cultivars (cv. Boyatiou', Veloudo', Clemson', and Pylaias') were sown on 13 May (1st sowing) and 2 June (2nd sowing). Plants were subjected to three N levels: F-1, F-2, and F-3 (150, 300, and 450mg N L-1). The 2nd sowing improved flower induction and pod set, without however affecting pod size. The number of seeds per pod was not affected by sowing time, but the mean 100 seed weight was generally lower in the 2nd sowing. In all cultivars, except cv. Veloudo' germination increased in the 2nd sowing mainly as a result of lower seed hardness. Germination was also improved by increasing N levels, or by seed storage, acid scarification, or seed priming.

Cover crops constitute one of the most promising agronomic practices towards a more sustainable agriculture. Their beneficial effects on main crops, soil and environment are many and various, while risks and disadvantages may also appear. Several legumes show a high potential but further research is required in order to suggest the optimal legume cover crops for each case in terms of their productivity and ability to suppress weeds. The additional cost associated with cover crops should also be addressed and in this context the use of grain legumes such as cowpea, faba bean and pea could be of high interest. Some of the aspects of these grain legumes as far as their use as cover crops, their genetic diversity and their breeding using conventional and molecular approaches are discussed in the present review. The specific species seem to have a high potential for use as cover crops, especially if their noticeable genetic diversity is exploited and their breeding focuses on several desirable traits.

Conyza canadensis has been reported to be the most frequent weed species that evolved resistance to glyphosate in various parts of the world. The objective of the present study was to investigate the effect of environmental conditions (temperature and light) on the expression levels of the EPSPS gene and two major ABC-transporter genes (M10 and M11) on glyphosate susceptible (GS) and glyphosate resistant (GR) horseweed populations, collected from several regions across Greece. Real-time PCR was conducted to determine the expression level of the aforementioned genes when glyphosate was applied at normal (1×; 533 g·a.e.·ha−1) and high rates (4×, 8×), measured at an early one day after treatment (DAT) and a later stage (four DAT) of expression. Plants were exposed to light or dark conditions, at three temperature regimes (8, 25, 35 °C). GR plants were made sensitive when exposed to 8 °C with light; those sensitized plants behaved biochemically (shikimate accumulation) and molecularly (expression of EPSPS and ABC-genes) like the GS plants. Results from the current study show the direct link between the environmental conditions and the induction level of the above key genes that likely affect the efficiency of the proposed mechanism of glyphosate resistance.