Temporal analysis of northern corn leaf blight (Exserohilum turcicum Pass. Leonard & Suggs) epidemics

Field trials were conducted in six locations in central-northern Córdoba, Argentina, using four maize hybrids with varying resistance to northern corn leaf blight (NCLB), caused by Exserohilum turcicum. Naturally occurring NCLB epidemics were evaluated. We analyzed disease severity (S%), disease progress curve (DPC), area under the disease progress curve, final severity (FS%) and apparent infection rate (r). Disease progress curves were simultaneously analyzed by fitting nonlinear epidemiological models (Gompertz and Logistic). Ballesteros and Villa María were the localities with the highest FS in susceptible hybrids (45% and 37.5%, respectively). Levels of FS were below 5% in Jesús María, Río Segundo and Freyre, and under 1% in El Tío. The highest AUDPC values were also observed in Ballesteros and Villa María (2150.1 and 1335.7, respectively). In the other locations, AUDPC values remained under 320, with statistically significant differences in all cases (p< 0.05). The resistant hybrid exhibited the lowest apparent infection rate compared to the other genotypes. Epidemic progress displayed, to varying degrees, sigmoid-shaped curves characteristic polycyclic diseases. On average, the Gompertz model best fitted disease progress data across all evaluated genotypes with an R² of 0.909 and an adjusted coefficient (R2*) of 0.849. The temporal analysis provided key epidemiological insights into the maize-NCLB pathosystem, supporting the development of effective management strategies. Highlights: Temporal analysis differentiated maize hybrids by resistance levels to NCLB. Gompertz model provided the best fit for NCLB epidemics. Final severity, AUDPC, and infection rates confirmed differences in hybrid resistance to NCLB. Understanding NCLB temporal dynamics supports the development of hybrid selection and integrated management strategies. Epidemiological tools enhance disease progress prediction and optimize NCLB control timing.Field trials were conducted in six locations in central-northern Córdoba, Argentina, using four maize hybrids with varying resistance to northern corn leaf blight (NCLB), caused by Exserohilum turcicum. Naturally occurring NCLB epidemics were evaluated. We analyzed disease severity (S%), disease progress curve (DPC), area under the disease progress curve, final severity (FS%) and apparent infection rate (r). Disease progress curves were simultaneously analyzed by fitting nonlinear epidemiological models (Gompertz and Logistic). Ballesteros and Villa María were the localities with the highest FS in susceptible hybrids (45% and 37.5%, respectively). Levels of FS were below 5% in Jesús María, Río Segundo and Freyre, and under 1% in El Tío. The highest AUDPC values were also observed in Ballesteros and Villa María (2150.1 and 1335.7, respectively). In the other locations, AUDPC values remained under 320, with statistically significant differences in all cases (p< 0.05). The resistant hybrid exhibited the lowest apparent infection rate compared to the other genotypes. Epidemic progress displayed, to varying degrees, sigmoid-shaped curves characteristic polycyclic diseases. On average, the Gompertz model best fitted disease progress data across all evaluated genotypes with an R² of 0.909 and an adjusted coefficient (R2*) of 0.849. The temporal analysis provided key epidemiological insights into the maize-NCLB pathosystem, supporting the development of effective management strategies. Highlights: Temporal analysis differentiated maize hybrids by resistance levels to NCLB. Gompertz model provided the best fit for NCLB epidemics. Final severity, AUDPC, and infection rates confirmed differences in hybrid resistance to NCLB. Understanding NCLB temporal dynamics supports the development of hybrid selection and integrated management strategies. Epidemiological tools enhance disease progress prediction and optimize NCLB control timing.  

Effects of climate change on nine rainfed Zea mays races in Chiapas, Mexico

Maize cultivation (Zea mays) is essential for Mexico from a nutritional, cultural and economic perspective. Scientific literature ignores the impact of anthropogenic causes of climate change on rainfed cultivation of Z. mays in Chiapas, Mexico, one of the poorest states in the country. Therefore, we modeled the feasibility of rainfed cultivation for nine races of rainfed maize for the years 2060 and 2100. The MaxEnt 4.4.4 algorithm modeled maize cultivation under two scenarios (4.5 and 8.5) for 2060 and 2100. Model inputs were 12 bioclimatic variables, 3 climatic variables, and 1 elevation variable. All layers were obtained from the WorldClim 2.1 project. By 2060, the suitable area for rainfed cultivation of the nine Z. mays races would drastically decrease under both modeled scenarios. By 2100, this area will decrease for seven races, and disappear for the Olotillo and Olotón races. To the best of our knowledge, this is the first study providing fundamental information on how climate change will negatively impact the nine Z. mays races in Chiapas, Mexico. This enables the development of sustainable management protocols or conservation strategies. Highlights: The MaxEnt algorithm proved very useful in modeling the effect of climate change on Zea mays. By the year 2060, the viable rainfed cultivation area of the nine mays races will drastically decrease under climate change scenarios 4.5 and 8.5 in Chiapas, México. By the year 2100, the viable rainfed cultivation area of seven mays races will drastically decrease under climate change scenarios 4.5 and 8.5, while Olotillo and Olotón maize races will completely disappear in Chiapas, México. “Maximum temperature of the warmest month” (Bio 5) was the variable with more contribution in 2060 (74% and 92.6%, for 4.5 and 8.5 scenarios, respectively) and in 2100 (59.3% and 89.1%, for 4.5 and 8.5 scenarios, respectively).Maize cultivation (Zea mays) is essential for Mexico from a nutritional, cultural and economic perspective. Scientific literature ignores the impact of anthropogenic causes of climate change on rainfed cultivation of Z. mays in Chiapas, Mexico, one of the poorest states in the country. Therefore, we modeled the feasibility of rainfed cultivation for nine races of rainfed maize for the years 2060 and 2100. The MaxEnt 4.4.4 algorithm modeled maize cultivation under two scenarios (4.5 and 8.5) for 2060 and 2100. Model inputs were 12 bioclimatic variables, 3 climatic variables, and 1 elevation variable. All layers were obtained from the WorldClim 2.1 project. By 2060, the suitable area for rainfed cultivation of the nine Z. mays races would drastically decrease under both modeled scenarios. By 2100, this area will decrease for seven races, and disappear for the Olotillo and Olotón races. To the best of our knowledge, this is the first study providing fundamental information on how climate change will negatively impact the nine Z. mays races in Chiapas, Mexico. This enables the development of sustainable management protocols or conservation strategies. Highlights: The MaxEnt algorithm proved very useful in modeling the effect of climate change on Zea mays. By the year 2060, the viable rainfed cultivation area of the nine mays races will drastically decrease under climate change scenarios 4.5 and 8.5 in Chiapas, México. By the year 2100, the viable rainfed cultivation area of seven mays races will drastically decrease under climate change scenarios 4.5 and 8.5, while Olotillo and Olotón maize races will completely disappear in Chiapas, México. “Maximum temperature of the warmest month” (Bio 5) was the variable with more contribution in 2060 (74% and 92.6%, for 4.5 and 8.5 scenarios, respectively) and in 2100 (59.3% and 89.1%, for 4.5 and 8.5 scenarios, respectively)

Essential oils and extracts from Argentinian northwest plants as potential biofungicides for olive and grapevine pathogens: in vitro studies

This work studies the effect of 12 botanical products from Argentinian northwest plants on spores and mycelium of Verticillium dahliae and Phaeoacremonium parasiticum, two pathogens of agronomic importance for the region. The fungi were exposed to essential oils (EOs) or ethanolic extracts (EEs), determining the percentage of germinated spores and mycelial growth. All tested EOs and EEs showed varying degrees of antifungal activity, dependent on plant species, extract type, pathogen, and targeted fungal structures. V. dahliae germination was completely inhibited by Zuccagnia punctata and Clinopodium gilliesii EOs. In experiments with EEs, Z. punctata EE was the most effective in suppressing spore germination of both fungi. The C. gilliesii EE also controlled V. dahliae germination. The EEs of Z. punctata, C. gilliesii and Lippia turbinata were the most active against mycelial growth. These three EEs had a fungistatic effect on P. parasiticum while Z. punctata and L. turbinata EEs showed a fungicidal effect on V. dahliae. The products obtained from Z. punctata, C. gilliesii and L. turbinata have potential as biocontrollers against V. dahliae and P. parasiticum. This is encouraging since no effective treatments are available for the diseases involving these pathogens. Highlights: Antifungal activity of plant-derived products varied depending on plant species, extract type, pathogen, and targeted fungal structures. Ethanolic extracts (EEs) showed higher antifungal activity than Essential oils (EOs). V. dahliae was more sensitive to plant product activity than P. parasiticum. The studied botanical products offer promising eco-friendly alternatives for integrated disease management in regional crops.This work studies the effect of 12 botanical products from Argentinian northwest plants on spores and mycelium of Verticillium dahliae and Phaeoacremonium parasiticum, two pathogens of agronomic importance for the region. The fungi were exposed to essential oils (EOs) or ethanolic extracts (EEs), determining the percentage of germinated spores and mycelial growth. All tested EOs and EEs showed varying degrees of antifungal activity, dependent on plant species, extract type, pathogen, and targeted fungal structures. V. dahliae germination was completely inhibited by Zuccagnia punctata and Clinopodium gilliesii EOs. In experiments with EEs, Z. punctata EE was the most effective in suppressing spore germination of both fungi. The C. gilliesii EE also controlled V. dahliae germination. The EEs of Z. punctata, C. gilliesii and Lippia turbinata were the most active against mycelial growth. These three EEs had a fungistatic effect on P. parasiticum while Z. punctata and L. turbinata EEs showed a fungicidal effect on V. dahliae. The products obtained from Z. punctata, C. gilliesii and L. turbinata have potential as biocontrollers against V. dahliae and P. parasiticum. This is encouraging since no effective treatments are available for the diseases involving these pathogens. Highlights: Antifungal activity of plant-derived products varied depending on plant species, extract type, pathogen, and targeted fungal structures. Ethanolic extracts (EEs) showed higher antifungal activity than Essential oils (EOs). V. dahliae was more sensitive to plant product activity than P. parasiticum. The studied botanical products offer promising eco-friendly alternatives for integrated disease management in regional crops

Epiphytic microorganisms associated with banana phyllosphere with potential antagonism to Black Sigatoka (Pseudocercospora fijiensis) in Los Ríos, Ecuador

Black Sigatoka (Pseudocercospora fijiensis) is the most important leaf spot disease of bananas worldwide, particularly affecting Cavendish banana, the most exported variety. Additionally, this pathogen has developed resistance to some effective fungicides, making its management increasingly difficult. Epiphytic microorganisms with potential antagonism to P. fijiensis were identified in conventional banana farms in the province of Los Ríos. Sampling areas were determined through zoning processes and selecting the cantons of Mocache, Valencia, Baba and Pueblo Viejo. Leaf tissue samples were collected from three farms per zone. Microorganisms were isolated and morphologically and molecularly characterised in nine farms in the cantons of Valencia (63 bacteria), Baba (39 bacteria), Pueblo Viejo (8 bacteria) and 8 genera of fungi including 15 species. The isolated bacteria presented macroscopic and microscopic characteristics with different shapes, elevations, edges, consistencies and pigmentations. Taxonomically, they belonged to the genera Bacillus and Cocos, 81% Gram-negative and 19% Gram-positive. The analysis conducted for sampling-site selection allowed the identification of different microbial behaviours. Highlights: Biological control offers a viable strategy to reduce reliance on agrochemicals in agricultural practices. The isolation and characterization of microorganisms are essential for researching and developing biological solutions applicable to banana cultivation. The data obtained provide crucial insights for formulating and developing bioinoculants.Black Sigatoka (Pseudocercospora fijiensis) is the most important leaf spot disease of bananas worldwide, particularly affecting Cavendish banana, the most exported variety. Additionally, this pathogen has developed resistance to some effective fungicides, making its management increasingly difficult. Epiphytic microorganisms with potential antagonism to P. fijiensis were identified in conventional banana farms in the province of Los Ríos. Sampling areas were determined through zoning processes and selecting the cantons of Mocache, Valencia, Baba and Pueblo Viejo. Leaf tissue samples were collected from three farms per zone. Microorganisms were isolated and morphologically and molecularly characterised in nine farms in the cantons of Valencia (63 bacteria), Baba (39 bacteria), Pueblo Viejo (8 bacteria) and 8 genera of fungi including 15 species. The isolated bacteria presented macroscopic and microscopic characteristics with different shapes, elevations, edges, consistencies and pigmentations. Taxonomically, they belonged to the genera Bacillus and Cocos, 81% Gram-negative and 19% Gram-positive. The analysis conducted for sampling-site selection allowed the identification of different microbial behaviours. Highlights: Biological control offers a viable strategy to reduce reliance on agrochemicals in agricultural practices. The isolation and characterization of microorganisms are essential for researching and developing biological solutions applicable to banana cultivation. The data obtained provide crucial insights for formulating and developing bioinoculants

Impact of Cry1Ac soybean (Glicine max) on biological and reproductive cycles and herbivory capacity of Spodoptera cosmioides and Spodoptera eridania (Lepidoptera: Noctuidae)

Increasing populations of Spodoptera cosmioides (Walker) and Spodoptera eridania (Stoll) have recently been detected in soybean crops in central Argentina. Besides being polyphagous, these species tolerate the Cry1Ac insecticidal toxin, expressed by genetically modified Bt soybean (MON89788 x MON87701). Consequently, when facing big populations, farmers often apply insecticides. This study aimed to determine the effects of Bt soybean on the consumption, biological cycle, and reproduction of both Spodoptera species. Larval feeding on Bt soybean led to a shorter pupal period (23% less than control) and a decreased leaf-area consumption for S. cosmioides (14% less than the non-Bt soybean). In S. eridania, the larval stage, adult longevity, larva-to-adult, and oviposition periods were reduced (11, 23, 13, and 30% shorter than control, respectively). Despite these reductions, both Lepidoptera species completed their reproductive cycles. These valuable findings help us understand the biology of these potential pests in Bt soybean crops in Argentina. Highlights: We studied the effect of the insecticidal toxin Cry1Ac expressed by genetically modified Bt soybean on the biological and reproductive cycle and foliar consumption of cosmioides and S. eridania. Spodoptera cosmioides registred a shorter duration of the pupal period. In eridania shorter duration of the larval and adult stages, larva-to-adult period and oviposition period were observed. Leaf-area consumption by cosmioides decreased in Bt soybean.Increasing populations of Spodoptera cosmioides (Walker) and Spodoptera eridania (Stoll) have recently been detected in soybean crops in central Argentina. Besides being polyphagous, these species tolerate the Cry1Ac insecticidal toxin, expressed by genetically modified Bt soybean (MON89788 x MON87701). Consequently, when facing big populations, farmers often apply insecticides. This study aimed to determine the effects of Bt soybean on the consumption, biological cycle, and reproduction of both Spodoptera species. Larval feeding on Bt soybean led to a shorter pupal period (23% less than control) and a decreased leaf-area consumption for S. cosmioides (14% less than the non-Bt soybean). In S. eridania, the larval stage, adult longevity, larva-to-adult, and oviposition periods were reduced (11, 23, 13, and 30% shorter than control, respectively). Despite these reductions, both Lepidoptera species completed their reproductive cycles. These valuable findings help us understand the biology of these potential pests in Bt soybean crops in Argentina. Highlights: We studied the effect of the insecticidal toxin Cry1Ac expressed by genetically modified Bt soybean on the biological and reproductive cycle and foliar consumption of cosmioides and S. eridania. Spodoptera cosmioides registred a shorter duration of the pupal period. In eridania shorter duration of the larval and adult stages, larva-to-adult period and oviposition period were observed. Leaf-area consumption by cosmioides decreased in Bt soybean

Preventive and curative effects of native yeasts on different Botrytis cinerea strains in “Superior Seedless” (Vitis vinifera L.) table grape cultured in Argentina

The fermenting grape must is a dynamic, stressful, and selective habitat where many yeast species compete. Specific yeasts isolated from this habitat can play a fundamental role in table grape biocontrol of fungal diseases. The present study evaluated 225 grapevine yeasts against four Botrytis cinerea strains isolated from “Superior Seedless” grapes, considering the possible antifungal action mechanisms. Eighteen enological yeasts (13 Saccharomyces and 5 non- Saccharomyces) showed preventive antifungal activity against the four native B. cinerea strains, with disease severity varying between 0 and 49.91%. These 18 strains also presented curative activity against at least one of the B. cinerea strains assayed (severity values between 0 and 45.99%). Considering action mechanisms, thirteen yeast strains inhibited mycelial growth of at least one B. cinerea strain during dual plating (antibiosis), “killer” activity, and volatile antifungal assays. Our results showed that 7 yeast strains affected conidial germination (CG) and germinal tube length (GTL) of at least one B. cinerea isolate. Two yeast strains occupied the same niche as 4 B. cinerea strains (NOI values > 0.90). All yeast strains exhibited at least two inhibitory action mechanisms against gray rot, except for BSc140 with one mechanism. The possibility of more than one mechanism per yeast strain makes biocontrol an effective tool to prevent and cure gray rot in table grapes. Highlights: We evaluated 225 native grapevine yeasts against four Botrytis cinereastrains isolated from “Superior Seedless” grapes, considering the possible antifungal action mechanisms. Saccharomyces (13) and 5 non- Saccharomyces(5) strains showed preventive antifungal activity against native  cinerea strains (4). Some grapevine yeasts (10 Saccharomycesy 4 non- Saccharomyces) presented curative activity against  cinerea strains. Grapevine yeasts, with preventive and curative activity, presented different antifungal mechanisms against  cinerea.  The fermenting grape must is a dynamic, stressful, and selective habitat where many yeast species compete. Specific yeasts isolated from this habitat can play a fundamental role in table grape biocontrol of fungal diseases. The present study evaluated 225 grapevine yeasts against four Botrytis cinerea strains isolated from “Superior Seedless” grapes, considering the possible antifungal action mechanisms. Eighteen enological yeasts (13 Saccharomyces and 5 non- Saccharomyces) showed preventive antifungal activity against the four native B. cinerea strains, with disease severity varying between 0 and 49.91%. These 18 strains also presented curative activity against at least one of the B. cinerea strains assayed (severity values between 0 and 45.99%). Considering action mechanisms, thirteen yeast strains inhibited mycelial growth of at least one B. cinerea strain during dual plating (antibiosis), “killer” activity, and volatile antifungal assays. Our results showed that 7 yeast strains affected conidial germination (CG) and germinal tube length (GTL) of at least one B. cinerea isolate. Two yeast strains occupied the same niche as 4 B. cinerea strains (NOI values > 0.90). All yeast strains exhibited at least two inhibitory action mechanisms against gray rot, except for BSc140 with one mechanism. The possibility of more than one mechanism per yeast strain makes biocontrol an effective tool to prevent and cure gray rot in table grapes. Highlights: We evaluated 225 native grapevine yeasts against four Botrytis cinereastrains isolated from “Superior Seedless” grapes, considering the possible antifungal action mechanisms. Saccharomyces (13) and 5 non- Saccharomyces(5) strains showed preventive antifungal activity against native  cinerea strains (4). Some grapevine yeasts (10 Saccharomycesy 4 non- Saccharomyces) presented curative activity against  cinerea strains. Grapevine yeasts, with preventive and curative activity, presented different antifungal mechanisms against  cinerea.

Overview of garlic waste management, circular economy and upcycling

In the last three years, 2 billion tonnes of untreated and dismissed agricultural wastes have been accumulated without adequate management of reuse or final disposal, resulting in dumping or burning. The circular economy concept has gained increasing global recognition for addressing environmental and economic challenges. Garlic, the second most common bulb vegetable cultivated worldwide, generates significant waste during its industrial processing, including husks, stalks, straws, and leaves. These wastes, representing 3.0 to 3.7 million tonnes of residual biomass per year, are currently underutilised, with the usual treatment involving dumping in landfills or direct burning, leading to increased soil and air pollution. In this review, we aim to encourage innovation by presenting a search for state-of-the-art garlic waste management. We identified studies about garlic residual biomass valorisation as raw material for obtaining different extracts and polymers, even energy or biofuels. Finally, following circular economy principles, we propose potential uses for garlic by-products to be repurposed or upcycled as materials within agricultural or other production chains. The information above reveals an increasing demand and interest in garlic waste valorisation. Future studies are needed to exploit garlic by-products as important sources of biopolymers and phytochemicals. Highlights: Garlic Waste Generation: Garlic production generates 3.0 to 3.7 million tonnes of residual biomass annually, including husks, stalks, and leaves. Current Disposal Methods: Garlic by-products are often disposed of through landfilling or burning, causing environmental pollution and resource loss. Valorisation Potential: Garlic residual biomass can be valorised into bioactive compounds, biopolymers, biofuels, and other sustainable materials. Circular Economy Approach: By-products from garlic can be integrated into circular economy models for use in agricultural and industrial production. Future Research Directions: Further research is needed to optimize garlic by-products for biopolymer and phytochemical production, enhancing sustainability.In the last three years, 2 billion tonnes of untreated and dismissed agricultural wastes have been accumulated without adequate management of reuse or final disposal, resulting in dumping or burning. The circular economy concept has gained increasing global recognition for addressing environmental and economic challenges. Garlic, the second most common bulb vegetable cultivated worldwide, generates significant waste during its industrial processing, including husks, stalks, straws, and leaves. These wastes, representing 3.0 to 3.7 million tonnes of residual biomass per year, are currently underutilised, with the usual treatment involving dumping in landfills or direct burning, leading to increased soil and air pollution. In this review, we aim to encourage innovation by presenting a search for state-of-the-art garlic waste management. We identified studies about garlic residual biomass valorisation as raw material for obtaining different extracts and polymers, even energy or biofuels. Finally, following circular economy principles, we propose potential uses for garlic by-products to be repurposed or upcycled as materials within agricultural or other production chains. The information above reveals an increasing demand and interest in garlic waste valorisation. Future studies are needed to exploit garlic by-products as important sources of biopolymers and phytochemicals. Highlights: Garlic Waste Generation: Garlic production generates 3.0 to 3.7 million tonnes of residual biomass annually, including husks, stalks, and leaves. Current Disposal Methods: Garlic by-products are often disposed of through landfilling or burning, causing environmental pollution and resource loss. Valorisation Potential: Garlic residual biomass can be valorised into bioactive compounds, biopolymers, biofuels, and other sustainable materials. Circular Economy Approach: By-products from garlic can be integrated into circular economy models for use in agricultural and industrial production. Future Research Directions: Further research is needed to optimize garlic by-products for biopolymer and phytochemical production, enhancing sustainability

The Native Dryland PGPR ‘Pseudomonas 42P4’ Promotes Adventitious Rooting in Woody Cuttings of Vitis spp.

This study evaluated the effect of two native PGPR strains from an arid region (Mendoza, Argentina) on the rooting of woody cuttings of Vitis spp. These strains are known for their growth-promoting capacity, including auxin production. Dormant V. vinifera cv. Malbec cuttings were grafted onto four rootstocks - 1103 Paulsen, 110 Richter, 101-14 MGt and SO4. Then, basal ends of these grafted cuttings and own rooted controls were incubated for 12 h in solutions of (1) Pseudomonas 42P4 at 107 CFU mL-1, (2) Enterobacter 64S1 at 107 CFU mL-1, (3) autoclaved LB medium, (4) water, and (5) a quick-dip immersion of Indole-3-butyric acid (IBA). After treatment, the cuttings were placed in a forcing chamber at 28°C and relative humidity ~100% for 21 days. Rooting parameters and scion-rootstock union percentages were recorded. Pseudomonas 42P4 significantly promoted rooting in Malbec own-rooted cuttings. However, Enterobacter 64S1 had negative or null effects.  Furthermore, Pseudomonas 42P4 enhanced rooting in Malbec grafted onto 1103 Paulsen, but not on 101-14 MGt, 110 Richter or SO4. This strain also improved graft union success on SO4, but did not affect the other rootstocks. These results suggest that a dryland native strain such as Pseudomonas 42P4 could sustainably enhance the quality of both own-rooted and grafted grapevine plants in commercial nurseries. Highlights: Pseudomonas 42P4, a native PGPR strain from arid soils, has genotype-specific effects during grapevine propagation. Pseudomonas 42P4 promotes rooting in own-rooted Malbec woody cuttings and in Malbec grafted onto 1103 Paulsen. Pseudomonas 42P4 might be a sustainable alternative to synthetic auxins in commercial nurseries.This study evaluated the effect of two native PGPR strains from an arid region (Mendoza, Argentina) on the rooting of woody cuttings of Vitis spp. These strains are known for their growth-promoting capacity, including auxin production. Dormant V. vinifera cv. Malbec cuttings were grafted onto four rootstocks - 1103 Paulsen, 110 Richter, 101-14 MGt and SO4. Then, basal ends of these grafted cuttings and own rooted controls were incubated for 12 h in solutions of (1) Pseudomonas 42P4 at 107 CFU mL-1, (2) Enterobacter 64S1 at 107 CFU mL-1, (3) autoclaved LB medium, (4) water, and (5) a quick-dip immersion of Indole-3-butyric acid (IBA). After treatment, the cuttings were placed in a forcing chamber at 28°C and relative humidity ~100% for 21 days. Rooting parameters and scion-rootstock union percentages were recorded. Pseudomonas 42P4 significantly promoted rooting in Malbec own-rooted cuttings. However, Enterobacter 64S1 had negative or null effects.  Furthermore, Pseudomonas 42P4 enhanced rooting in Malbec grafted onto 1103 Paulsen, but not on 101-14 MGt, 110 Richter or SO4. This strain also improved graft union success on SO4, but did not affect the other rootstocks. These results suggest that a dryland native strain such as Pseudomonas 42P4 could sustainably enhance the quality of both own-rooted and grafted grapevine plants in commercial nurseries. Highlights: Pseudomonas 42P4, a native PGPR strain from arid soils, has genotype-specific effects during grapevine propagation. Pseudomonas 42P4 promotes rooting in own-rooted Malbec woody cuttings and in Malbec grafted onto 1103 Paulsen. Pseudomonas 42P4 might be a sustainable alternative to synthetic auxins in commercial nurseries

Dry mass production, nutrient accumulation and decomposition rate of cover crops intercropped with a Theobroma cacao full-sun system

Cover crops play a crucial role in promoting soil protection, enhancing organic matter content, facilitating nutrient cycling, and improving overall soil quality. The objective of this study was to evaluate the biomass production, nutrient accumulation, and decomposition rate of cover crops intercropped with Theobroma cacao trees in a full-sun system. The research was conducted in Ilhéus, Bahia state, Brazil. The experimental design employed randomized blocks with three treatments, four decomposition times, and four replications. The treatments consisted of three cover crops: 1) pigeon pea (Cajanus cajan); 2) brachiaria (Urochloa decumbens); and 3) spontaneous vegetation. Decomposition rates were evaluated using litter bags at specific intervals: 0, 47, 94, 116, and 136 days after field deposition. Dry biomass production and nutrient accumulation by the cover crops were also measured. Spontaneous vegetation and brachiaria treatments exhibited the highest potassium accumulation, while no significant differences were observed among the treatments for the other evaluated nutrients. Moreover, spontaneous vegetation and brachiaria demonstrated higher decomposition rates, with 16.7% and 26.7% of the deposited material remaining at the end of the 136-day study period, respectively. In contrast, the decomposition rate of pigeon pea proved to be slower, with a remaining dry mass of 38.3%, indicating longer persistence in the soil, and consequently a greater half-life time. The cover crops investigated in this study are regarded as promising options for intercropping with cocoa, as they exhibit an average dry mass production of 10 Mg ha-1. This value falls within the desired range for conservationist systems. When selecting species for intercropping, it is crucial to consider the decomposition rates these plants. This consideration ensures that the soil surface remains covered for an extended duration, leading to enhanced conservation and improvement of the soil’s physical, chemical, and biological properties. Soil conservation can be effectively achieved by choosing cover crop species with slower decomposition rates, thereby contributing to the overall health and quality of the soil. Highlights: This study evaluated biomass production, nutrient accumulation, and decomposition rate of cover crops intercropped with Theobroma cocoa trees in a full-sun system. The cover crops investigated exhibit an average dry mass production of 10 Mg ha-1. Spontaneous vegetation and brachiaria treatments exhibited the highest potassium accumulation. Pigeon pea proved to be slower decomposition rate and largest remaining dry masso on the soil. In contrast, Spontaneous vegetation and brachiaria demonstrated higher decomposition rates, consequently less remaining dry mass.Cover crops play a crucial role in promoting soil protection, enhancing organic matter content, facilitating nutrient cycling, and improving overall soil quality. The objective of this study was to evaluate the biomass production, nutrient accumulation, and decomposition rate of cover crops intercropped with Theobroma cacao trees in a full-sun system. The research was conducted in Ilhéus, Bahia state, Brazil. The experimental design employed randomized blocks with three treatments, four decomposition times, and four replications. The treatments consisted of three cover crops: 1) pigeon pea (Cajanus cajan); 2) brachiaria (Urochloa decumbens); and 3) spontaneous vegetation. Decomposition rates were evaluated using litter bags at specific intervals: 0, 47, 94, 116, and 136 days after field deposition. Dry biomass production and nutrient accumulation by the cover crops were also measured. Spontaneous vegetation and brachiaria treatments exhibited the highest potassium accumulation, while no significant differences were observed among the treatments for the other evaluated nutrients. Moreover, spontaneous vegetation and brachiaria demonstrated higher decomposition rates, with 16.7% and 26.7% of the deposited material remaining at the end of the 136-day study period, respectively. In contrast, the decomposition rate of pigeon pea proved to be slower, with a remaining dry mass of 38.3%, indicating longer persistence in the soil, and consequently a greater half-life time. The cover crops investigated in this study are regarded as promising options for intercropping with cocoa, as they exhibit an average dry mass production of 10 Mg ha-1. This value falls within the desired range for conservationist systems. When selecting species for intercropping, it is crucial to consider the decomposition rates these plants. This consideration ensures that the soil surface remains covered for an extended duration, leading to enhanced conservation and improvement of the soil’s physical, chemical, and biological properties. Soil conservation can be effectively achieved by choosing cover crop species with slower decomposition rates, thereby contributing to the overall health and quality of the soil. Highlights: This study evaluated biomass production, nutrient accumulation, and decomposition rate of cover crops intercropped with Theobroma cocoa trees in a full-sun system. The cover crops investigated exhibit an average dry mass production of 10 Mg ha-1. Spontaneous vegetation and brachiaria treatments exhibited the highest potassium accumulation. Pigeon pea proved to be slower decomposition rate and largest remaining dry masso on the soil. In contrast, Spontaneous vegetation and brachiaria demonstrated higher decomposition rates, consequently less remaining dry mass

Challenges in germination of Neltuma caldenia in semi-arid regions: optimization of germination protocols, influence of saline stress and seed quality

Global climate change presents challenges to arid and semi-arid ecosystems, impacting native species such as Neltuma caldenia, endemic to Argentina. This underscores the importance of understanding germination processes for both conservation programs and the restoration of degraded areas. We aimed to evaluate the germination rate of N. caldenia seeds from the south Espinal, using various scarification methods (chemical, mechanical and physical), and temperatures (25-30°C). Additionally, we investigate the effects of accelerated aging (0-96 h at 45°C and 100 relative humidity) and different saline solution concentrations during germination (0-0.6 M NaCl). Our results show that all scarification treatments effectively break seed dormancy while temperature significantly affects germination rates. Prolonged storage (0 to 96h) decreased seed viability. Moderate NaCl levels (0-0.2 M) did not affect germination, but higher concentrations inhibited it completely, with a threshold of -1.81 MPa osmotic potential. Understanding the impact of environmental stressors on seed germination can inform the development of effective conservation strategies among these climate change pressures. Highlights: Shorter duration chemical scarification method (10 minutes) and mechanical scarification were statistically more efficient than the other treatments. Temperature significantly influences germination capacity, with optimal rates achieved at 30–35°C, aligning with the precipitation patterns of the region. caldenia seeds may demonstrate greater resilience to high-temperature and humidity conditions, probably due to higher vigor. Salinity tolerance during germination extends up to -0.90 MPa, highlighting adaptability to saline environments of caldenia compared to other Neltuma species.Global climate change presents challenges to arid and semi-arid ecosystems, impacting native species such as Neltuma caldenia, endemic to Argentina. This underscores the importance of understanding germination processes for both conservation programs and the restoration of degraded areas. We aimed to evaluate the germination rate of N. caldenia seeds from the south Espinal, using various scarification methods (chemical, mechanical and physical), and temperatures (25-30°C). Additionally, we investigate the effects of accelerated aging (0-96 h at 45°C and 100 relative humidity) and different saline solution concentrations during germination (0-0.6 M NaCl). Our results show that all scarification treatments effectively break seed dormancy while temperature significantly affects germination rates. Prolonged storage (0 to 96h) decreased seed viability. Moderate NaCl levels (0-0.2 M) did not affect germination, but higher concentrations inhibited it completely, with a threshold of -1.81 MPa osmotic potential. Understanding the impact of environmental stressors on seed germination can inform the development of effective conservation strategies among these climate change pressures. Highlights: Shorter duration chemical scarification method (10 minutes) and mechanical scarification were statistically more efficient than the other treatments. Temperature significantly influences germination capacity, with optimal rates achieved at 30–35°C, aligning with the precipitation patterns of the region. caldenia seeds may demonstrate greater resilience to high-temperature and humidity conditions, probably due to higher vigor. Salinity tolerance during germination extends up to -0.90 MPa, highlighting adaptability to saline environments of caldenia compared to other Neltuma species