Chili Pepper Plants Research Articles

Synthesis of agro-industrial wastes/sodium alginate/bovine gelatin-based polysaccharide hydrogel beads: Characterization and application as controlled-release microencapsulated fertilizers

Synthesis of novel agro-industrial wastes/sodium alginate/bovine gelatin-based polysaccharide hydrogel beads, micromeritic/morphometric characteristics of the prepared formulations, greenhouse trials using controlled-release microencapsulated fertilizers, and acute fish toxicity testing were conducted simultaneously for the first time within the scope of an integrated research. In the present analysis, for the first time, 16 different morphometric features, and 32 disinct plant growth traits of the prepared composite beads were explored in detail within the framework of a comprehensive digital image analysis. The hydrogel beads composed of 19 different agro-industrial wastes/materials were successfully synthesized using the ionotropic external gelation technique and CaCl2 as cross-linker. According to micromeritic characteristics, the ionotropically cross-linked beads exhibited 77.86 ± 3.55 % yield percentage and 2.679 ± 0.397 mm average particle size. The dried microbeads showed a good swelling ratio (270.02 ± 80.53 %) and had acceptable flow properties according to Hausner's ratio (1.136 ± 0.028), Carr's index (11.94 ± 2.17 %), and angle of repose (25.03° ± 5.33°) values. The settling process of the prepared microbeads was observed in the intermediate flow regime, as indicated by the average particle Reynolds numbers (169.17 ± 82.81). Experimental findings and non-parametric statistical tests reveal that dried fertilizer matrices demonstrated noteworthy performance on the cultivation of red hot chili pepper plant (Capsicum annuum var. fasciculatum) according to the results of greenhouse trials. Surface morphologies of the best-performing fertilizer matrices were also characterized by Scanning Electron Microscopy. Moreover, the static fish bioassay experiment confirmed that no abnormalities and acute toxic reactions occurred in shortfin molly fish (Poecilia sphenops) fed with dried leaves of red hot chili pepper plants grown with formulated fertilizers. This study showcased a pioneering investigation into the synthesis of microcapsules using synthesized hydrogel beads along with digital image processing for bio-waste management and sustainable agro-application.

First report of pepper yellow leaf curl Thailand virus infecting hot chili in central Vietnam and Laos.

Hot chili pepper (Capsicum annuum) cultivation has been on the rise in South East Asia to meet export demands. In Thailand, the top chili exporter in South East Asia, chili production has been severely hampered by pepper yellow leaf curl disease (YLCD) caused by the begomovirus pepper yellow leaf curl Thailand virus (PepYLCThV) (Chiemsombat et al., 2018; Suwor et al., 2021). In the neighbouring countries of Laos and Vietnam, a limited survey of chili fields (200 plants in total) in Savannakhet (Savannakhet University campus, n = 150), Laos and Quang Nam province (Ka Dang commune, Dong Giang district, n = 50), central Vietnam in 2023 led to the finding of eight plants (5 in Laos and 3 in Vietnam) exhibiting YLCD-like symptoms, which included bright yellow color in young leaves and leaf curl and mosaic chlorosis in mature leaves (Fig. S1). Total DNA was extracted from leaves of two symptomatic plants (one from Savannakhet and one from Quang Nam) using a cetyltrimethylammonium bromide-based DNA extraction protocol (Doyle & Doyle, 1987; Nguyen et al., 2023). Next, PCR were performed using newly designed PepYLCThV-specific primers based on PepYLCThV sequences in GenBank (Table 1). PCR products of expected sizes were observed in samples with disease symptoms, but not from DNA extracted from C. annuum (cv. VA.99999) grown at the Institute of Biotechnology in Thua Thien Hue, Vietnam (Fig. S2). The amplicons were Sanger sequenced (Apical Scientific, Selangor, Malaysia) and the complete bipartite genome sequence of two isolates ('Sava01' from Laos and 'QNam01' from Vietnam) were obtained. The sequences of the DNA-A component from isolates 'Sava01' (GenBank PP437580) and 'QNam01' (GenBank PP437581) exhibited the highest sequence identity of 99.2% and 94.7% with the PepYLCThV isolate 'ChiangDaoS1' (GenBank OM677627), respectively (Table 2). Conversely, the sequences of the DNA-B component from the isolates 'Sava01' (GenBank PP437579) and 'QNam01' (GenBank PP437582) exhibited the highest similarity of 91.8% and 90.9% with the PepYLCThV isolate 'KKN601' (GenBank MW715820), respectively (Table 2). These results confirmed the presence of PepYLCThV in hot chili pepper plants exhibiting YLCD-like symptoms in central Vietnam and Laos. Infectious clones of PepYLCThV DNA-A and DNA-B (isolate 'QNam01') were created based on the pLX-AS vector as described by Pasin (2022), and transformed into Agrobacterium tumefaciens EHA105. The resulting bacteria were cultured in LB broth containing rifampicin (25 μg/mL) and kanamycin (50 μg/mL) at 28°C and used for agroinoculation of Nicotiana benthamiana (n = 6) and C. annuum (cv. VA.99999, n = 6) (4-6 leaf plants) as described by Pasin (2022). In all N. benthamiana plants, agroinoculation with both DNA-A and DNA-B infectious clones caused stunted growth, severe leaf curl, with yellow and white patches 21 days post inoculation (Fig. S3). In C. annuum plants, symptom expression, which included leaf curl and stunted leaves with yellow mosaic patterns, was observed in two out of six inoculated plants six weeks postinoculation (Fig. S3). PCR assays confirmed the presence of PepYLCThV DNA in N. benthamiana and C. annuum symptomatic leaves (Fig. S4). To our knowledge, this is the first report of pepper yellow leaf curl Thailand virus in hot chili pepper in Laos and central Vietnam. Appropriate containment and management strategies should be developed and implemented to control the spread of this disease in hot chili pepper crops in both countries.

Full-length transcriptome sequencing of pepper fruit during development and construction of a transcript variation database.

Chili pepper is an important spice and a model plant for fruit development studies. Large-scale omics information on chili pepper plant development continues to be gathered for understanding development as well as capsaicin biosynthesis. In this study, a full-spectrum transcriptome data of eight chili pepper tissues at five growth stages using the Oxford Nanopore long-read sequencing approach was generated. Of the 485 351 transcripts, 35 336 were recorded as reference transcripts (genes), while 450 015 were novel including coding, lnc, and other non-coding RNAs. These novel transcripts belonged to unknown/intergenic (347703), those retained introns (26336), and had multi-exons with at least one junction match (20333). In terms of alternative splicing, retained intron had the highest proportion (14795). The number of tissue-specific expressed transcripts ranged from 22 925 (stem) to 40 289 (flower). The expression changes during fruit and placenta development are discussed in detail. Integration of gene expression and capsaicin content quantification throughout the placental development clarifies that capsaicin biosynthesis in pepper is mainly derived from valine, leucin, and isoleucine degradation as well as citrate cycle and/or pyrimidine metabolism pathways. Most importantly, a user-friendly Pepper Full-Length Transcriptome Variation Database (PFTVD 1.0) (http://pepper-database.cn/) has been developed. PFTVD 1.0 provides transcriptomics and genomics information and allows users to analyse the data using various tools implemented. This work highlights the potential of long-read sequencing to discover novel genes and transcripts and their diversity in plant developmental biology.

Evaluation of three different DNA extraction methods for the detection of Pepper yellow leaf curl virus (PepYLCV) by Polymerase Chain Reaction

Abstract Pepper yellow leaf curl virus (PepYLCV) from the genus Begomovirus infecting Chili pepper plant can cause significant yield losses. PepYLCV infection can lead the development of mosaic yellow, mottled pattern and yellowing leaves, which can be challenging in disease management and control. Developing effective detection methods for PepYLCV is a critical disease management and crop loss mitigation. The Begomovirus viruses have extremely low viral concentrations and are limited to the phloem and vascular system. DNA extraction is an important step in PepYLCV detection. This study aimed to evaluate the efficiency of three DNA extraction methods: phenol-based extraction, CTAB-based extraction, and the GeneJET Plant Genomic DNA Purification Kit (Thermo Scientific™). These methods were evaluated for their performance to identified the presence of PepYLCV DNA and provide accurate results for further analyses. DNA samples were extracted from two varieties including Red Habanero and F8 012328-6-2-1-1-3-1, and were subsequently amplified using Krusty Homer’s primers. The results showed that all three extraction methods possess the capability to identify PepYLCV. Based on the results, DNA extraction employing the CTAB-based method yields DNA with higher concentration and purity levels. Additionally, this method proves to be cost-effective and proficient in generating higher DNA concentrations.

Priming for drought resistance: UV-C flashes triggered pipecolate accumulation and dehydration avoidance in Capsicum chinense Jacq. but induced no growth or metabolic costs

Ultraviolet (UV) radiation has been increasingly studied as an elicitor of plant defense against biotic and abiotic stress. The biological responses to these stimuli can be either beneficial or detrimental and are not yet fully understood. We treated chili pepper plants with UV-C flashes (1 kJ·m−2, 2 s, 254 nm) three times for 1 week before imposing progressive drought stress for 2 weeks. In the absence of drought, plants treated with UV-C showed identical height, leaf number, water content, and stomatal conductance to those of the control plants. Analysis of leaf metabolic fingerprints covering large portions of central and secondary metabolism also revealed a limited effect of UV-C treatment on the metabolome, including the accumulation of pipecolate. In contrast, when subjected to drought, plants treated with UV-C exhibited enhanced water retention in leaves and significant changes in the metabolome. Further investigation of metabolic responses revealed that variations in major water stress markers were significantly mitigated by UV-C pretreatment. Overall, the results suggest that UV-C treatments induce priming based on the activation of systemic defense effectors and the absence of harmful symptoms, resulting in partial but significant avoidance of dehydration and reduced drought-related metabolic consequences. This paves the way for agricultural applications to concurrently manage multiple stresses and to study the specific mechanisms at work in UV-C-primed plants.

Physiological, Biochemical, and Molecular Response in Siete Caldos Chili Pepper Plants (Capsicum frutescens) Exposed to Water Deficit

Drought, exacerbated by climate change, represents a growing challenge for agriculture, significantly impacting on crops such as chili peppers (Capsicum), essential in the global diet. This work evaluated the response to water stress by suspending irrigation in Siete Caldos chili pepper plants (Capsicum frutescens). Control plants were watered every 48 h, while stress was induced in the test plants by withholding irrigation for 14 days, followed by an evaluation of recovery through rehydration on day 15. Growth parameters such as the fresh weight of the aerial part, root length, and number of flower buds showed significant differences between the two groups from the eighth day onwards. However, physiologically and biochemically stress-induced decreased relative water content, membrane stability, and chlorophyll content, coupled with increased electrolyte leakage, proline content, and antioxidant activity (catalases and peroxidases), were observed starting on the third day. These effects were more severe on day 14. At the molecular level, the expression of stress response genes (AP2, LOX2, CAT, CuSOD, MnSOD, and P5CS) was quantified at days 3, 14, and 15, revealing differences in transcript levels between the treatments. Finally, rehydration in the stressed plants resulted in the recovery of the evaluated parameters and a survival rate of 100%. Therefore, chili pepper has tolerance mechanisms that allow it to withstand a period of 14 days without irrigation, without reaching its permanent wilting point, and it can recover if conditions improve. This study underscores the complexity of plant responses and tolerance mechanisms to drought, providing insights into the behavior of semi-domesticated species.

Classification of Chili Fruit Diseases Using Deep Convolutional Neural Network Transfer Learning

Chili peppers are among the highest-value agricultural commodities, often experiencing significant price fluctuations due to supply constraints. The rainy season frequently leads to crop failures caused by diseases affecting chili plants. Existing methods often struggle to accurately differentiate between similar symptoms on leaves and fruits, leading to misdiagnosis and ineffective disease management strategies. Early detection of these diseases, which manifest as symptoms on the leaves and fruits, is crucial for effective pest management. Common diseases include anthracnose, characterized by dry brown spots on the fruit, and fruit rot, where the interior of the fruit decays while the skin remains intact. Identifying these diseases promptly is essential for applying appropriate treatments to ensure optimal yields.In this study, a comprehensive approach is taken to classify diseases in chili pepper plants (Capsicum annuum L.) by incorporating both leaf and fruit segmentation. The research employs Deep Convolutional Neural Networks with Transfer Learning (DCNN) to enhance detection capabilities. The findings reveal that for leaf disease classification, fewer neurons in additional layers yield better accuracy and reduced loss, while for fruit disease classification, a more complex model with additional neurons is necessary. This underscores the need for balancing model complexity to achieve optimal performance and prevent overfitting, particularly in distinguishing between leaf and fruit diseases.

IoT-Based Rainfall Monitoring System for Chili Farming Land

This research focuses on the design and implementation of a rainfall monitoring system for chili pepper farms using Internet of Things (IoT) technology. The rainfall monitoring system consists of a transmitter system, a receiver system, the Thingspeak platform as a database, and a weather station application that can be accessed via a mobile device. The weather station application is built using the MIT App Inventor platform. In the testing phase, the system successfully collected data from two sensors used, namely the rainfall intensity sensor and the raindrop sensor. The test results showed that the data obtained from the rainfall intensity sensor was 0.25 inches and the raindrop sensor was 1. This result shows that there was no rain during the test. This rain intensity and raindrop data can provide farmers with an overview of the weather conditions in the chili pepper farm. So, with this rainfall monitoring system, farmers can monitor the condition of their agricultural land in real-time. The collected data can help farmers to care for chili pepper plants more effectively and adapt to environmental changes. In addition, this system is expected to increase the productivity of chili pepper farming because it uses a more precise and responsive approach to changes in environmental conditions on the chili pepper farm.

Evaluation of the application of suspensions of iron oxide magnetic nanoparticles functionalized with quaternized chitosan and phosphates on yellow maize and chili pepper plants

We have applied aqueous suspensions of magnetite-maghemite nanoparticles functionalized with quaternized chitosan and phosphate groups on yellow maize (Zea Mays) and chili pepper (Capsicum annuum) plants, at greenhouse conditions, to evaluate if any beneficial or adverse effects are produced by these nanocomposites in the development of these kind of plants at morphological and physiological level. Phytotoxicity assays with yellow maize seeds showed excellent germination percentages in all treatments evaluated, as well as increasing indicators of biomass and root length of germinated seeds for suspensions of nanoparticles with iron contents up to 50 ppm. Suspensions of nanoparticles with iron contents higher than 50 ppm led to decreasing indicators of biomass and root length of germinated seeds compared to lower iron contents. Iron contents of 100 ppm showed indicators lower than those of the control, suggesting phytotoxic effect of these nanocomposites for iron contents above 100 ppm. Measurements of morphological and physiological parameters of plants of both crops in greenhouse conditions, treated with suspensions of nanoparticles with iron-phosphorus contents of 25 − 3, 35 − 4 and 45 − 5 ppm, commercial fertilizer as positive control and tap water as a negative control did not evidence any phytotoxic or beneficial effect. The results suggest that, although these nanocomposites did not have a noticeable effect as vehicles of micro and macro nutrients as iron and phosphorus in the evaluated plants, they did not produce phytotoxic effects on them at the morphological and physiological level for iron contents less than 50 ppm, as they showed adequate growth and development.

Enhancing chili pepper (Capsicum annuum L.) resistance and yield against powdery mildew (Leveillula taurica) with beneficial bacteria

BackgroundLeveillula taurica is an obligate pathogen that causes powdery mildew on chili pepper (Capsicum annuum L.) which is considered one of the most serious diseases for the crop.ResultsLeveillula taurica was isolated from infected pepper plants in Assiut Governorate, Egypt. Pathogenicity test was performed, and it was found that the pathogen can cause the symptoms of powdery mildew on the pepper plant. Under greenhouse conditions, treatment with Bacillus thuringiensis MW740161.1, Pseudomonas fluorescens, and Bacillus subtilis cultures resulted in a significant reduction in conidial germination of the pathogen (69.07, 29.55, and 19.58%, respectively). Spraying chili pepper plants with the microorganisms effectively reduced the powdery mildew's disease severity. Also, treatment with the bacterial strains resulted in a significant (P 0.05%) increase in the yield of chili pepper. Based on the findings, it appears that the use of B. thuringiensis, as foliar spraying, significantly induced resistance of chili pepper plants against L. taurica and stimulated many biochemical functions in the plant. Also, it increased the crop yield compared to all other treatments.ConclusionsThis study recommends B. thuringiensis as a viable alternative to harmful pesticides, and it is feasible to formulate an appropriate fungicide for the sustainable green production of chili peppers. The B. thuringiensis can increase the resistance of chili pepper plant to L. taurica the causal pathogen of powdery mildew.

Deep learning pest detection on Indonesian red chili pepper plant based on fine-tuned YOLOv5

.This research developed a pest detection model for Indonesian red chili pepper based on fine-tuned YOLOv5. Indonesian red chili pepper is the third largest vegetable commodity produced in Indonesia. Pest attacks disrupt the quantity and quality of crop yields. To control pests effectively, it is necessary to detect the type of pest correctly. A viable solution is to leverage computer vision and deep learning technologies. However, no previous studies have developed a pest detection model for Indonesian red chili pepper based on this technology. YOLOv5 is a variant of the YOLO object detection algorithm, which has major advantages in terms of computation cost and execution speed. The dataset comprises 4,994 image files collected from a chili plantation in Bengkulu province, Indonesia, covering 4 different classes and a total of 10,683 pests. The image is 1216 x1216 px with the smallest, largest, and average object dimensions of 2%, 35%, and 4% of the image dimensions. The training model used is fine-tuning YOLOv5s with variations of patience as an early stop parameter of 100, 200, and 300. The evaluation of the trained model is based on train loss, validation loss, and mAP@0.5:0.95, the best-trained model is the 445th epoch on patience 100 with the best confidence value of 0.321 and the highest TF1 of 0.74. From the best-trained model testing on the test dataset, the mAP@0.5 performance for all classes is 81.3%. The model not only detected large pests but was also able to detect objects that were small in size compared to the image size. The best-trained model's best mAP@0.5 performance and speed are 82.6% and 20 ms/image, or 50 fps on NVIDIA P100 GPU.

Antagonistic potential of endophytic fungi against Meloidogyne enterolobii, M. incognita and Nacobbus aberrans sensu lato

Root-knot nematodes limit horticultural crop production in Mexico where management is mainly based on nematicides that represent a risk to health and the environment. Thus, biological alternatives, such as the use of endophytic fungi, are currently being developed. The objective of this research was to isolate, identify and evaluate the antagonistic potential of endophytic fungi against the root-knot nematodes Meloidogyne enterolobii, M. incognita and the false root-knot nematode Nacobbus aberrans sensu lato (s.l.) occurring in Mexico. Endophytic fungi from chili pepper and tomato plants with a low root galling index were isolated from three localities in Sinaloa state (Villa Juárez, Valle de Culiacan and La Cruz de Elota) and one in Mexico City (Xochimilco). Fourteen isolates from leaves and roots were evaluated to assess: i) the ability to promote growth in chili pepper and tomato plants, ii) the degree of parasitism on nematode eggs and second-stage juveniles (J2), and iii) the nematostatic and nematicidal effect of their filtrates on the J2. In the trials, the three most effective endophytic fungal isolates were Chaetomium globosum (S1TH2), Echria macrotheca (S3RT2) and Stagonospora trichophoricola (XRC3). All three fungal isolates increased growth on chili pepper plants after application, but only two (S3RT2 and XRC3) did so on tomato plants. S1TH2 parasitized M. enterolobii eggs; S3RT2 and XRC3 eggs of N. aberrans s.l.; S3RT2 also parasitized M. incognita eggs and J2 of N. aberrans s.l. The S1TH2 filtrate was nematostatic for M. incognita and N. aberrans s.l., the XRC3 filtrate was nematostatic for N. aberrans s.l., and the S3RT2 filtrate was nematostatic and nematicidal for the J2 of N. aberrans s.l. The results obtained indicate that these isolates could be involved in natural regulation and biological control of root-knot nematodes.

Feeding rumen-protected Capsicum oleoresin to dairy cows during the transition period and early lactation: Effects on nutrient digestibility, blood metabolites, and performance

Capsicum oleoresin (CAP), a plant extract derived from chili pepper plants, contains bioactive compounds reported to influence the energy metabolism in dairy cows. This study investigated the effects of feeding rumen-protected CAP during the transition period and early lactation on total-tract apparent digestibility of nutrients, serum metabolites [glucose, urea-N, non-esterified fatty acids (NEFA), and beta-hydroxybutyrate (BHB)], and milk yield and composition in dairy cows. Twenty-four healthy Holstein cows (12 multiparous and 12 primiparous) were enrolled to this study at − 4 wk from the expected calving date. Animals were blocked according to parity and expected calving date. Cows within block were randomly assigned to a control (CON) treatment without feed additives or to the CAP treatment, dietary supply of rumen-protected CAP at 100 mg/d. Pre-partum and post-partum data were analyzed separately. Dry matter intake and related dietary variables were not affected by treatments during the pre- or post-partum period. No differences were detected on digestibility of DM, organic matter, or crude protein during the pre-partum and post-partum periods. Serum metabolite concentrations were similar between treatment groups either during the pre-partum or post-partum periods. Milk yield tended to be greater (P = 0.07) in cows fed CAP than CON (31.7 and 28.5 kg/d, respectively). Fat-corrected milk yield was increased (P = 0.03) by feeding CAP. Milk fat yield (1.20 vs. 1.05 kg/d) and feed efficiency (1.72 vs. 1.50 kg milk/kg DM intake) were significantly greater (P ≤ 0.03) in cows fed CAP than CON. Feeding rumen-protected CAP at 100 mg/d during the transition period and early lactation increased fat-corrected milk yield, and improved milk fat and feed efficiency of dairy cows.

Phenotypic leaf character of katokkon chili pepper (Capsicum chinense Jacq.) result of polyploidization with colchicine

The formation of a new variety of katokkon chili through mutation breeding using colchicine was conducted in this study. This study aims to determine the effect of the phenotypic leaf characters of katokkon chili pepper resulting from polyploidization with colchicine. The study was conducted at the Malino Horticulture Seed Garden Installation, Tinggimoncong District, Gowa Regency, South Sulawesi at an altitude of 1047 m above sea level. This study used samples of katokkon chili pepper plants that had been induced by colchicine and were analyzed using flow cytometry. The results showed that treatment with 0.10% colchicine concentration and 48 hours of soaking time and 0.20% colchicine concentration and 24 and 48 hours of soaking time that is tetraploid detected plant affected on darker leaf color and irregular branching shape compared to wild-type. At the same time, tetraploid plants leaf length, width and thickness did not show significant differences with diploid and mixoploid plants.

Effects of holy basil (Ocimum sanctum) on viral disease of chili (Capsicum annum L.) under mixed crop cultivation

Chili is one of the important commodities in Indonesia. Chili cultivation faces many obstacles, leading to a decrease in production, such as virus infections. Yellow leaf curl and curly top viruses are groups of viruses that are often found in chili fields. This research was conducted to investigate the effect of intercropping (basil-chili) in suppressing viral diseases, especially yellow leaf curl and curly top viruses. A Randomized block design was used for this research, including intercropping and monoculture. The parameters observed in this study included disease incidence and intensity, the number and weight of chilies. Symptoms of virus infection include leaf curl, yellowing, and stunting. The disease has been reported to be transmitted by insect vectors, such as Aphis gossypii and Bemisia tabaci. The results showed that the incidence and intensity of yellow leaf curl and curly top virus diseases in chili pepper and basil plants were not significantly different in each treatment. The number of healthy chilies and their weight were also not significantly different. Damaged chilies are fruits that have been attacked by fruit flies. Basil intercropped with chilies attracts fruit flies, which affects the quantity and weight of the harvested chilies. The population of B. tabaci was significantly different in each treatment, while A. gossypii did not show significant differences among the treatments. Intercropping basil and chili increased the population of A. gossypii, while the population of B. tabaci decreased in this treatment. These two insect pests are vectors for yellow leaf curl and curly top viruses.

Well known microbial plant growth promoters provoke plant growth suppression and increase chili pepper wilt caused by the root pathogen Phytophthora capsici

Microbial plant growth promoters (MPGP) are known to improve crop nutrition and root health. Here we examined the effects of individual and combined inoculation of chili pepper (variety Camino Real) with the known plant growth promoters Rhizophagus irregularis (isolate BEG87) and a commercial product of Azospirillum brasilense on chili pepper growth and biocontrol against the oomycete root pathogen Phytophthora capsici (isolate CH11). In a greenhouse pot experiment, unfertilized ten-week-old chili pepper plants with individual and combined inoculation of R. irregularis and A. brasilense were confronted with P. capsici, and four weeks later plants were harvested and scored for plant growth and disease severity. Surprisingly, both MPGP not only decreased plant growth, but also promoted root rot caused by P. capsici. This increased disease severity with P. capsici root rot in mycorrhizal chili pepper was further corroborated in a second greenhouse pot experiment with inert growth substrate and mineral fertilization. In conclusion, individual and combined inoculation with R. irregularis and A. brasilense may not only cause plant growth suppression in chili pepper plants, but also increase root rot caused by P. capsici.

Yahualica tree seedling chile production (Capsicum annuum) on different substrates and its behavior during the development of the crop

In order to observe the differences between substrates in the production of Yahualica chili pepper (Capsicum annuum) seedling and plant, in the field and greenhouse at the University Center of Cs. Biological and Agricultural of the University of Guadalajara, this investigation was carried out, where six substrates were evaluated: Promix-GLX, Promix-FLX, Sunshine-3, Berger-BN2, Germinaza and 50% Germinaza + 50% Earthworm Humus. In seedlings, the following were evaluated: Emergence Speed, Emergence Percentage, Stem Thickness, Seedling Length, Number of Leaves, Fresh Weight Aerial Part, Fresh Weight root, aerial part dry weight and root dry weight, and during plant development in field and greenhouse: Plant height, and Fresh weight of ripe fruit. Significant differences were found between treatments (P≤0.05) in the seedling and plant quality variables. Consequently with the mixture of 50% Germinaza + 50% Earthworm Humus, Berger BN2 and Sunshine 3, the best seedling quality was obtained. And moreover the best plant development was observed in the greenhouse, with an average plant height of 139 cm and a fresh fruit yield of 651 g. When germinaza was combined with earthworm humus (50:50), the results were significant to obtain vigorous plants, high percentage of emergence.

Ebb and flow versus constant water level on the sweet banana chili pepper (Capsicum annuum) production in an aquaponic system

Bell siphons are used in aquaponic systems to create rising and falling water levels in plant culture beds that facilitates water exchanges and elevates dissolved oxygen (DO) although this may also remove nutrient rich organic debris from the plant culture bed. Sweet banana chili pepper (Capsicum annuum) plants were aquaponically grown until maturity and then further cultured in a media-filled bed with or without a bell siphon for one month in triplicate. Water quality was measured throughout as well as the total chili number, weight, mineral composition and sugar levels. Channel catfish (30 individuals/replicate; initial weight = 289 g ± 10.2) were fed twice/day for 5 days/week. Results showed that a bell siphon significantly increased DO in both the fish and plant culture tanks, but dissolved nitrogen and pH were similar. Fish growth, survival and feeding efficiency were similar among treatments. The total count (982 and 747) and weight of chilies (7450 and 7413 g) were similar without or with a bell siphon, but individually, chilies were significantly heavier with a bell siphon. Soluble and insoluble sugars were unaffected but among the tested minerals, sodium, potassium, calcium and zinc were significantly elevated in chilies cultured without a bell siphon. The lower mineral content was likely due to the bell siphon removing excess organic debris from the media-filled plant culture bed that would otherwise be mineralized. Based on these findings and under the culture conditions, bell siphons may not provide benefits to plant production and the lower DO may be mitigated by providing additional aeration in the plant culture bed.

Synergistic effect of trans-zeatin and silymarin on mitigation of cadmium stress in chili pepper through modulating the activity of antioxidant enzymes and gene expressions

Many human activities, including waste disposal and the use of synthetic phosphate fertilizers, increase the concentration of cadmium (Cd) in the environment and harm plants and human health. Therefore, it is imperative to find effective solutions to overcome this problem. As plant biostimulants, trans-zeatin-type cytokinin (tr-Z) and silymarin (Sm) can act as anti-heavy metal agents, effectively ameliorating Cd damage to plants. In a pot trial, the impacts of foliar treatment with tr-Z (40 μM), Sm (400 μM), or tr-Z + Sm (25 +250 μM, respectively, applied sequentially) on biomass production, yield, photosynthetic efficiency, osmoregulators, antioxidative defense system, and transcript levels of enzyme-related genes of chili pepper under normal or Cd (500 μM) stress were investigated. Cadmium stress elevated the levels of superoxide (O2•), hydrogen peroxide (H2O2), electrolyte leakage (EL), malondialdehyde (MDA), and Cd, while negatively affecting biomass production, photosynthetic efficiency, and defense system components. Exogenous tr-Z and/or Sm attenuated the Cd-induced negative impacts on plants, highlighting that the integrative tr-Z + Sm treatment was more efficient than the single treatments. The tr-Z + Sm treatment decreased contents of roots, shoot, and fruit Cd by 66–91%, and reduced levels of O2• and H2O2, MDA, and EL by 45%, 73%, 51%, and 72%, respectively, correlated with increased tr-Z and Sm contents by 38–66%. Exogenous tr-Z + Sm increased biomass production by 99–134%, photosynthetic efficiency attributes by 31–169%, and antioxidants (ascorbate, proline, glutathione, and phenolics) by 33–123%. The levels of proteins and total leaf and fruit capsaicin were higher in Cd-stressed plants treated with tr-Z + Sm. Furthermore, the co-application of tr-Z + Sm up-regulated the activities of superoxide dismutase (SOD), glutathione reductase (GR), ascorbate peroxidase (APX), and catalase (CAT) enzymes by 38–43%, and maximized transcript level of genes-encoding enzymes in stress-exposed plants. As a result, the integrative tr-Z + Sm treatment is highly recommended to mitigate Cd stress impacts in chili pepper plants.

Biocontrol activity of endophytic bacteria from cocoa against Phytophthora sp. and Colletotrichum sp.

Cocoa (Theobroma cacao L.) and chili pepper (Capsicum annuum L.) are commonly cultivated by farmers, and in some cases, both crops are grown together in intercropping systems. The main pathogen infected cocoa is the Phytophthora sp. fungus, which causes fruit rot, stem cancer, and leaf blight, while Colletotrichum sp. causes anthracnose in chili pepper plants. The ability of endophytic bacteria to inhibit the growth of fungi and bacterial pathogens is well known. In this study, the biocontrol ability of endophytic bacteria against fungal pathogens was tested, and a biocontrol preliminary test was also observed by examining their potential inhibition on Chromobacterium violaceum called antiquorum sensing test. Endophytic bacteria were isolated from cocoa plants, while Phytophthora and Colletotrichum were isolated from cocoa and chili pepper plants that showed symptoms of fruit rot and anthracnose. A total of 34 endophytic bacterial isolates were successfully obtained, with 10 isolates from leaves (DK), 12 isolates from branches (RK), and 12 isolates from roots (KA) of cocoa plant ICCRI 4. Sixteen isolates showed quorum sensing ability, which AHL degradation index ranging from 0.44 – 1.56. Antagonistic tests showed that 11 out of 16 isolates had strong antibiosis against Phytophthora sp., with inhibition zones ranging from 0.6-1.35 cm. Meanwhile, 10 out of 16 isolates had strong antibiotics against Colletotrichum sp., with clear zones ranging from 0.6 – 1.1 cm. The three best endophytic bacterial isolates that had a combination of antiquorum sensing ability on C. violaceum and biocontrol against Phytophthora sp. and Colletotrichum sp. were RK 11, KA 1, and KA 8. [Keywords: antagonist, ahl lactonase, plant beneficial microorganism]