Chili Pepper Cultivars Research Articles

Transcriptome analysis integrated with changes in cell wall polysaccharides of different fresh-cut chili pepper cultivars during storage reveals the softening mechanism

Cell wall disassembly and transcriptomic changes during storage of two fresh-cut chili pepper cultivars displaying contrasting softening rates were investigated. Results showed that Hangjiao No. 2 (HJ-2) softened more rapidly than Lafeng No. 3 (LF-3). Compared with LF-3, HJ-2 had a higher content of WSP, more side chains of RG-I in three pectin fractions, and higher activities of PME, PL, and β-Gal at day-0. During storage, HJ-2 showed more markable pectin solubilization, more severe degradation in CSP and NSP, and greater loss of side chains from RG-I in three pectin fractions, which were correlated with increased activities of PG and α-L-Af. Furthermore, the higher up-regulation of PG (LOC107870605, LOC107851416) and α-L-Af (LOC107848776, LOC107856612) were screened in HJ-2. In conclusion, the different softening rate between cultivars was not only due to the fundamental differences in pectin structure but also pectin degradation regulated by related enzymes and gene expression levels.

Bacterial Leaf Spot Susceptibility Screening of Chili Pepper Cultivars Using qPCR Determination of Xanthomonas euvesicatoria pv. euvesicatoria Titers.

Bacterial leaf spot is a serious disease of chili pepper (Capsicum spp.) caused by Xanthomonas euvesicatoria pv. euvesicatoria. Conventional resistance screening is time and resource intensive. It was considered that a quick and simple determination of cultivar susceptibility could be achieved through estimating bacterial titers of inoculated plants. A SYBR quantitative polymerase chain reaction (qPCR)-based assay was compared with conventional PCR, then used to detect and enumerate pathogen titers in serial dilutions and DNA extracted from infected plant leaves. The qPCR detection limit was approximately 1 CFU µl-1, 10 times more sensitive than conventional PCR. A linear correlation (R2 = 0.994) was obtained from the standard curve comparing plate-truthed serial dilutions of the pathogen with the qPCR cycle threshold. Six strains were used to inoculate cultivars Hugo and Warlock. One strain, X. euvesicatoria pv. euvesicatoria BRIP62403, was consistently the most virulent based on visual symptoms and pathogen titers in planta inferred by qPCR performed on DNA extracted from infected leaves 2 and 6 weeks postinoculation. Visual observations 6 weeks after inoculation were highly correlated (R2= 0.8254) to pathogen titers. The qPCR method was used to categorize 20 chili pepper cultivars 2 weeks after inoculation. A high positive correlation (R2 = 0.6826) was observed between visual scoring and pathogen titers from 20 chili pepper cultivars, facilitating categorization of susceptible, intermediate, and resistant cultivars. The qPCR approach developed here facilitates susceptibility screening of chili pepper cultivars at an early stage of selection and could be readily adapted to a range of other pathosystems.

In-vitro Antioxidant and Anti-Inflammation Activities of Ethanol Extract from “Bang Chang” Thai Cultivar Chili Pepper (Capsicum annuum Var. acuminatum)

Chili peppers (Capsicum spp.) are really important crops in several Asian countries. In Thailand, chili pepper cultivars are also a wide range of flavors, colors, shapes, and spiciness levels. The cultural importance in Thai cuisine. The “Bang Chang chili pepper” (Capsicum annuum var. acuminatum), a Thai cultivar of capsicum, had first cultivated in Bang Chang subdistrict, Samut Songkhram, Thailand. This study aimed to determine capsaicin, phenolic compounds and flavonoids and screen ethanol extract’s biological activities. The extract’s average capsaicin and total phenolic content (TPC) was 10.4 ± 0.3 (g/100 mL and 2.50 ± 0.13 mg GAE/g, while it could not determine flavonoids. The low amount of capsaicin in extract was defined this cultivars as non-pungent capsicum (0-700 Scoville Heat Units, SHU). This extract was strongly scavenged NO and DPPH radicals (IC50 = 0.09 ± 0.02 and 14.88 ± 1.59 mg/mL). There was also exerted in-vitro anti-inflammation activity by suppression of albumin breakdown (IC50 = 0.51 ± 0.05 mg/mL), which, can comparable to control, diclofenac diethyl ammonium (IC50 = 0.45 ± 0.01 mg/mL). Therefore, lipid peroxidation was weakly inhibited (IC50 >1,000 mg/mL) and unable to trap metals compared to vitamin E and EDTA. According to our finding, this extract was exerted biological properties like antioxidant and anti-inflammation, as well as being non-pungent, it can be used externally for medicinal purposes like as a muscle relaxant and massage oil to reduce subcutaneous fat. This extract can be used as a condiment in Asian recipes and other healthful dishes

Nutritional Composition, Capsaicin Content and Enzyme Inhibitory Activities from “Bang Chang” Thai Cultivar Chili Pepper (Capsicum annuum Var. acuminatum) after Drying Process

Chili pepper cultivars come in a broad variety of tastes, colors, sizes, and spiciness levels due to various growth conditions. The significance of different chili peppers and other spices in Thai cuisine may be seen in dishes. This study evaluated the nutritional composition and capsaicin content from “Bang Chang” Thai cultivar chili pepper after drying, and the inhibition of lipase, tyrosinase and elastase enzymes from its oil and ethanol extracts. The nutritional composition of sun-dried chili pepper was high dietary fiber and beta-carotene, which were significantly high amount portion of Thai recommended dietary intake (RDI). According to calculations and definitions, “Bang Chang chili pepper” is a non-pungent Capsicum (0-700 SHU) since it contains a low amount of capsaicin. Total phenolic content was more abundant in ethanol extract (2.50 ± 0.13 mg GAE/g) than oil extract (1.05 ± 0.05 mg GAE/g). Compared to the positive control orlistat (IC50 = 3.26 ± 0.28 mg/mL), an anti-lipase drug, ethanol extract was 2.0 times more lipase inhibitory. In addition, ethanol extract was mildly anti-tyrosinase, while oil extract was non-activity. The anti-lipase activity of ethanol extract was due to phenolic content rather than capsaicin contained and this enzyme inhibition may act on active site. We found that ethanol extract of “Bang Chang” cultivar chili pepper yielded higher TPC content and more effective anti-lipase than oil extract. The finding provided benefits on applying this chili pepper on anti-lipase use and weight management.

Capsaicinoids and volatile flavor compounds profile of Sichuan hotpot as affected by cultivar of chili peppers during processing

Sichuan hotpot oil is a distinctive traditional Chinese cuisine, and chili pepper is an essential material for its flavor formation. In this study, the effect of chili pepper cultivars on capsaicinoids as well as Sichuan hotpot oil volatile compounds were examined. Gas chromatography-mass spectrometry (GC–MS) and chemometrics were employed to ascertain the differences between volatile components and flavor. The results showed that the EJT hotpot oil had the highest color intensity of 34.8, and the SSL hotpot oil had the highest capsaicinoids content of 1.536 g/kg. The results of QDA showed distinct differences among hotpot oils in terms of all sensory properties. A total of 74 volatile components were detected. Aldehydes, ketones, esters, and acids were the dominant volatile compounds formed in 18 hotpot oil samples and showed a significant difference, suggesting that they played a key role in flavor contribution and distinguishing the flavor differences between different hotpot oils. The PCA results well distinguished 18 kinds of hotpot oil.

Plant Growth, Yield, and Quality of Containerized Heirloom Chile Pepper Cultivars Affected by Three Types of Biostimulants

Peppers (Capsicum annuum) are one of the most widely cultivated vegetable crops, with per capita consumption of bell and chile peppers being 11.4 and 7.7 pounds in 2017. Biostimulants are an emerging sustainable alternative to enhance plant health by increasing photosynthetic activity, stress tolerance, and nutrient uptake through various modes of action. The effects of different biostimulant applications largely remain unknown in containerized heirloom pepper production. This study evaluated plant growth, yield, and fruit quality of nine heirloom chile pepper cultivars, including ‘Anaheim Chili,’ ‘Ancho or Poblano,’ ‘Big Jim,’ ‘Cayenne Purple,’ ‘Chile de Arbol,’ ‘Jamaica Hot Red,’ ‘Mulato Isleno,’ ‘Padron,’ and ‘Pasilla Bajio’ in a container production system throughout the years of 2020 and 2021. Each cultivar was treated with three types of biostimulants, including Tribus® Original (a mixture of Bacillus bacterias), Vitazyme (containing plant growth regulators and B vitamins), C-Bio CPS (seaweed extract of Ascophyllum Nodosum), and water as control. Pepper cultivars varied in yield and quality, including fruit length, diameter, single fruit weight, and fruit color in both years. ‘Anaheim Chili,’ ‘Big Jim,’ and ‘Jamaica Hot Red’ produced highest marketable yields similarly, with ‘Chile de Arbol’ and ‘Pasilla de Bajio’ producing the lowest marketable yields in both years. Biostimulant application did not affect marketable yield either in 2020 or 2021 but enhanced fruit quality, including fruit length, diameter, and green coloration.

High-throughput Characterization of Fruit Phenotypic Diversity among New Mexican Chile Pepper (Capsicum spp.) Using the Tomato Analyzer Software

Fruit architecture and morphology-related traits are among the determinants of fruit diversity and are major contributors to yield and yield potential in chile pepper (Capsicum spp.). This study aimed to characterize 105 genotypes of a Capsicum diversity panel consisting of cultivars, breeding lines, landrace, and wild species belonging to twelve different pod (fruit) types, for 32 morphometric Tomato Analyzer (TA) descriptors. Hierarchical cluster analysis grouped the genotypes into eight clusters based on the TA descriptors. A multivariate principal component analysis yielded two principal components, PC1 and PC2, which explained 53.24% and 10.11% of the variation in fruit diversity, respectively. The basic measurements—namely, perimeter, area, width midheight, maximum width, height midwidth, maximum height, and curved height were the most discriminating descriptors with a maximum contribution to the overall fruit shape. There was a strong, positive correlation for basic measurements and fruit shape index, whereas blockiness was negatively correlated with distal angle macro. Additive genetic effects and high heritability for the fruit traits were observed. Results of this study will provide valuable information to breed high-yielding chile pepper cultivars based on fruit morphology traits.

Perfil antioxidante de cultivares de pimenta e pimentão por dois métodos de extração

ABSTRACT Chili peppers are among the most important vegetables in the world. The demand of this fruit reveals a noticeable rapid increasing, which importance is mainly due to its nutraceutical composition. These fruits are rich in capsaicinoids, phenolic compounds, carotenoids, and others, including vitamins. In this study, a comparative evaluation between two extraction methods of bioactive compounds of fourteen chili pepper cultivars was performed. Two extraction methods for antioxidants, the time-solvent and the ultrasound were evaluated. The design of the experiment was completely randomized with three repetitions where variables evaluated were total phenolic compounds, flavonoids content, antioxidant capacity and capsaicin. Results showed that the phenolic compounds oscillated between 48.7 - 634.1 mg GAE/100 g dry weight (DW), the flavonoids content varied from 1 - 97 mg QE/100 g DW, the antioxidant activity from 65 - 348 µmol Trolox/g DW and the capsaicin content oscillated from 0.3 - 922 mg/100 g DW. The extraction method with higher values of bioactive compounds for each of the chili pepper types was the ultrasound for all the measured variables.

Reducing Water Salinity at Flowering Stage Decreases Days to Flowering and Promotes Plant Growth and Yield in Chile Pepper

Water scarcity is a major problem for crop production around the world including Southwestern United States and growers are increasingly using groundwater for agriculture in Southern New Mexico. Most of the groundwater in New Mexico is brackish and continuous long-term use could lead to salt accumulation in the soil. Reverse osmosis (RO) can desalinate brackish groundwater (BGW), however, environmentally safe disposal of RO concentrate is costly. This greenhouse study evaluated the effects of BGW and RO concentrate at various growth stages of two chile pepper cultivars, NuMex Joe E. Parker and NuMex Sandia Select. Five salinity treatments were applied to plants, three of them used saline waters of 0.6 (control), 4.0 (BGW), and 8.0 dS/m (RO) throughout the growing season, whereas the other two changed waters of 4.0 and 8.0 dS/m to waters of 2.0 and 6.0 dS/m from the beginning of the flowering stage. Number of flowers, days to flowering, relative plant heights, relative fresh biomass, fruit yields, photosynthetic rate (Pn), stomatal conductivity (gS), and actual evapotranspiration (ETa) significantly decreased with increasing irrigation water salinity levels. Concentrations of Mg2+, Na+, and Cl− in plants increased with increasing water salinity levels. Changing to irrigation with reduced salinity waters of 2.0 and 6.0 dS/m at the flowering stage initiated reproductive development more rapidly and alleviated the adverse influence of salinity on the number of flowers of chile pepper, plant height, Pn, as well as fresh shoot and fruit weight than that with continuous irrigation with electrical conductivity (EC) of 4.0 dS/m and 8.0 dS/m beyond the flowering stage. Irrigation that practices a change from high salinity to lower salinity at the flowering stage can optimize the use of saline irrigation water for growing chile peppers.

Biocontrol of Anthracnose Disease on Chili Pepper Using a Formulation Containing Paenibacillus polymyxa C1

Anthracnose disease on chili pepper has been known to seriously interfere with the plant growth and obviously reduce the yield. The disease is caused by Colletotrichum spp. In Bali, Indonesia, six species of Colletotrichum have been identified: Colletotrichum scovillei, C. acutatum, C. nymphaeae, C. gloeosporioides, C. truncatum, and C. fructicola. However, among them the C. scovillei was found to be the most prevalent cause of anthracnose on chili pepper in Bali. Two species of antagonist against C. scovillei, namely Paenibacillus polymyxa C1 and Bacillus siamensis C7B, have been identified. In this study the effectiveness of P. polymyxa C1 formulation was evaluated under greenhouse condition on chili pepper cultivars Cabe Besar. Application of formulation was conducted by a mini hand sprayer once to five times with a week interval. Results of the study showed that treatment with five applications significantly (p < 0.05) reduced the disease incidence, disease intensity, and the yield loss of chili pepper cultivar Cabe Besar. Alose relationship was observed between the number of applications with disease intensity, with coefficient of determination (R2) at 0.929. These results revealed that the formulation of P. polymyxa C1 effectively control the anthracnose disease on chili pepper, particularly on chili pepper cultivar Cabe Besar, and thus can be recommended for field testing to confirm its stability under field conditions.

Effect of Organic and Bio-fertilizer on some growth and physiological indicators of chili pepper cultivars

Effect of Organic and Bio-fertilizer on some growth and physiological indicators of chili pepper cultivars

First report of a resistance-breaking strain of Tomato spotted wilt orthotospovirus infecting Capsicum annuum carrying the Tsw resistance gene in South Korea.

Tomato spotted wilt orthotospovirus (TSWV) was first reported in 2004 from paprika in South Korea (Kim et al., 2004), where it is currently widespread. TSWV infections were reported in chili pepper, tomato, weeds, and ornamental plant species in South Korea (Choi et al., 2014; Choi and Choi, 2015; Yoon et al., 2016; Yoon et al., 2018; Yoon et al., 2019). One of the best strategies for TSWV management is planting resistant cultivars containing the Tsw gene. In 2019 virus-like symptoms were observed in chili pepper (Capsicum annuum) plants bearing the Tsw gene in Anseong-si, South Korea. The infected chili peppers showed mosaic and wilting followed by necrosis on leaves and fruits in the field. To identify the causal virus, symptomatic leaf samples were analyzed using ImmunoStrip kits (Agdia, USA); we detected three pepper-infecting viruses: Pepper mild mottle virus, Cucumber mosaic virus, and TSWV. TSWV was only detected from 40 naturally infected chili pepper plants exhibiting virus-like symptoms. To further confirm the presence of TSWV (named TSWV-P1), we amplified reverse-transcription polymerase chain reaction (RT-PCR) products for L, M, and S RNA segments using tospovirus-specific and TSWV-specific primers (Batuman et al., 2014). Expected fragments of 445, 868, and 777 bp in length were amplified and sequenced. The complete genome sequences of TSWV-P1 from a symptomatic chili pepper plant were also determined using TSWV-specific primers (Choi et al., 2014; Lian et al., 2013). The complete genome sequences of TSWV-P1 were deposited to GenBank (LC549179, LC549180, and LC549181). The sequences of each fragment were identical to a consensus sequence, showing 99.1%, 98.5%, and 98.6% identity with TSWV-L, M, and S RNA (KP008132, AY744492, and KP008134), respectively. These results clearly showed only a single TSWV infection among the naturally infected chili pepper plants, without reassortment between TSWV and another tospovirus. To confirm whether TSWV-P1 is a resistance-breaking (RB) strain, Nicotiana rustica was mechanically inoculated with sap from leaves of the infected pepper samples to propagate TSWV-P1. A non-RB TSWV isolate (TSWV-Kor-lisianthus) from lisianthus was used as a control (Yoon et al., 2017). Two resistant (with Tsw) and two susceptible chili pepper cultivars (20 plants per cultivar) were mechanically inoculated with sap from leaves of the TSWV-infected N. rustica. The incidence rates of disease caused by TSWV-P1 were 90-100% for resistant and 95-100% for susceptible cultivars. In contrast, TSWV-Kor-lisianthus caused symptoms only in the susceptible pepper cultivars (90-100% incidence). TSWV infection in representative plants was confirmed using the TSWV- ImmunoStrip kit and RT-PCR. The NSs gene of TSWV-P1 consists of 1,404 nucleotides (468 amino acids); sequence analysis of the TSWV-P1 NSs gene showed high nucleotide (99.7%) and amino acid identities (99.8%) with the NSs sequences of two TSWV isolates (FR693035, CBX24121). Protein sequence analysis of TSWV-P1 NSs revealed that no amino acid mutation was associated with those of a representative TSWV RB strain, as previously described (Almási et al., 2017), suggesting that TSWV-P1 is a RB strain. Because this TSWV-P1 can overcome resistance conferred by the Tsw gene in commercially grown chili pepper cultivars, it represents a potential threat to pepper production in South Korea.

Single nucleotide polymorphisms reveal genetic diversity in New Mexican chile peppers (Capsicum spp.)

BackgroundChile peppers (Capsicum spp.) are among the most important horticultural crops in the world due to their number of uses. They are considered a major cultural and economic crop in the state of New Mexico in the United States. Evaluating genetic diversity in current New Mexican germplasm would facilitate genetic improvement for different traits. This study assessed genetic diversity, population structure, and linkage disequilibrium (LD) among 165 chile pepper genotypes using single nucleotide polymorphism (SNP) markers derived from genotyping-by-sequencing (GBS).ResultsA GBS approach identified 66,750 high-quality SNP markers with known map positions distributed across the 12 chromosomes of Capsicum. Principal components analysis revealed four distinct clusters based on species. Neighbor-joining phylogenetic analysis among New Mexico State University (NMSU) chile pepper cultivars showed two main clusters, where the C. annuum genotypes grouped together based on fruit or pod type. A Bayesian clustering approach for the Capsicum population inferred K = 2 as the optimal number of clusters, where the C. chinense and C. frutescens grouped in a single cluster. Analysis of molecular variance revealed majority of variation to be between the Capsicum species (76.08 %). Extensive LD decay (~ 5.59 Mb) across the whole Capsicum population was observed, demonstrating that a lower number of markers would be required for implementing genome wide association studies for different traits in New Mexican type chile peppers. Tajima’s D values demonstrated positive selection, population bottleneck, and balancing selection for the New Mexico Capsicum population. Genetic diversity for the New Mexican chile peppers was relatively low, indicating the need to introduce new alleles in the breeding program to broaden the genetic base of current germplasm.ConclusionsGenetic diversity among New Mexican chile peppers was evaluated using GBS-derived SNP markers and genetic relatedness on the species level was observed. Introducing novel alleles from other breeding programs or from wild species could help increase diversity in current germplasm. We present valuable information for future association mapping and genomic selection for different traits for New Mexican chile peppers for genetic improvement through marker-assisted breeding.

Impact of colored water pillows on yield and water productivity of pepper under greenhouse conditions

This study was conducted to investigate the effects of colored water pillows on yield and water productivity of two pepper cultivars under greenhouse conditions in 2018 and 2019. Irrigation treatments were arranged as: drip without mulching, black water pillow, blue water pillow, drip+black mulching and drip+blue mulching. The first year, total plant water consumption amount was about 421 mm for drip and 301 mm for the other treatments and respectively as 439 and 305 mm in the second year. In both years, approximately 38% less water was applied in water pillow irrigation treatments. Significant differences were not observed in yields of water pillow and drip+mulching treatments, but drip irrigation treatments were found to be significantly different from the other treatments in both years. For Captain capia and Yellow Stone chili pepper cultivars, as the average of two years, the highest yields were obtained from water pillow treatments as 39.65 and 32.3 t ha−1, respectively, and the lowest yields were obtained from the drip irrigation treatments as 28.9 and 22.7 t ha−1. There were significant differences in irrigation water productivity (IWP) and water productivity (WP) values of drip irrigation and the other treatments. For Captain capia and Yellow Stone chili pepper, as the average of two years, the highest IWP values were obtained from the water pillow treatments as 121.3 and 96.8 kg ha−1 mm−1, and the lowest IWP value was obtained from the drip irrigation treatments as 65 kg ha−1 mm−1. Similarly, the highest WP values were obtained from the water pillow treatments as 129.5 and 103.25 kg ha−1 mm−1, and the lowest WP value was obtained from the drip treatments as 52.5 kg ha−1 mm−1. A great energy saving was achieved with water pillow method. The amount of energy used in water pillow was about 2% and 5% of the energy used in drip and drip+mulching treatments, respectively. In both years, water pillow and drip+mulching treatments had higher soil temperatures than drip treatment as 1.3 °C. Weeds were not encountered in water pillows and drip+mulching treatments. In conclusion, present findings revealed that water pillows were clearly superior to drip irrigation. Although yield values of water pillows and drip+mulching treatments were not significantly different, no extra energy demand, inherent mulching characteristics and quite low labor costs have made water pillows more advantages over drip+mulching treatments.

Application of anthracnose resistance-associated molecular markers in the detection of resistant chili pepper cultivars in Vietnam

Introduction: Colletotrichum species is responsible for anthracnose, a worldwide serious disease, causing an important loss in chili pepper production. Therefore, screening disease resistant and sensitive chili pepper cultivars in Vietnam is important not only for in-depth studies of disease resistance-associated molecular mechanisms but also for chili production improvement via molecular marker-assisted breeding in Vietnam.
 Methods: To this end, in this study, two Colletotrichum isolates were obtained from the infected fruits collected from chili pepper (Capsicum annuum) fields in Tra Vinh province. According to the morphology analysis and the sequencing results of the internal transcribed spacer (ITS) regions, these isolates were identified as C. scovillei and C. acutatum. In order to identify the anthracnose-resistant chili pepper cultivars, the pathogenicity test was conducted by infecting fully developed green fruits of eleven chili pepper cultivars with the two isolated Colletotrichum strains.
 Results: CN404 and HNCS were the two strongest anthracnose-resistant cultivars. Two chili pepper cultivars, TV3 and PN400, showed different resistance tendencies to each Colletotrichum isolates. Four different SSR molecular markers were used in this study to identify the potential molecular markers associated with anthracnose resistance traits in chili pepper cultivars. Among the four examined markers, HpmsE126 was detected in two anthracnose-resistant chili pepper cultivars, suggesting its close relation to the anthracnose resistance trait in chili pepper.
 Conclusion: Given that two of the three most anthracnose-resistant cultivars, CN404 and TV3, possess HpmsE126 marker, this marker can be used to detect anthracnose-resistant lines in chili pepper breeding in Vietnam.

Phenotypic Characterization and Ethnobotanical Inventory of Chili Pepper (Capsicum spp.) Cultivars in Cebu Island, Philippines

Phenotypic Characterization and Ethnobotanical Inventory of Chili Pepper (Capsicum spp.) Cultivars in Cebu Island, Philippines

Water Use and Yield Responses of Chile Pepper Cultivars Irrigated with Brackish Groundwater and Reverse Osmosis Concentrate

Freshwater availability is declining in most of semi-arid and arid regions across the world, including the southwestern United States. The use of marginal quality groundwater has been increasing for sustaining agriculture in these arid regions. Reverse Osmosis (RO) can treat brackish groundwater, but the possibility of using an RO concentrate for irrigation needs further exploration. This greenhouse study evaluates the water use and yield responses of five selected chile pepper (Capsicum annuum L.) cultivars irrigated with natural brackish groundwater and RO concentrate. The four saline water treatments used for irrigation were tap water with an electrical conductivity (EC) of 0.6 dS m−1 (control), groundwater with EC 3 and 5 dS m−1, and an RO concentrate with EC 8 dS m−1. The evapotranspiration (ET) of all chile pepper cultivars decreased and the leaching fraction (LF) increased, particularly in the 5 dS m−1 and 8 dS m−1 irrigation treatments. Based on the water use efficiency (WUE) of the selected chile pepper cultivars, brackish water with an EC ≤ 3 dS/m could be used for irrigation in scarce freshwater areas while maintaining the appropriate LFs. A piecewise linear function resulted in a threshold soil electrical conductivity (ECe) ranging between 1.0–1.3 dS m−1 for the tested chile pepper cultivars. Both piecewise linear and sigmoid non-linear functions suggested that the yield reductions in chile peppers irrigated with Ca2+ rich brackish groundwater were less than those reported in studies using an NaCl-dominant saline solution. Further research is needed to understand the role of supplementary calcium in improving the salt tolerance of chile peppers.

Screening of Chilli Pepper Genotypes as a Source of Capsaicinoids and Antioxidants under Conditions of Simulated Drought Stress.

In many regions of the world, the production of vegetable crops is limited by a deepening water crisis. Drought stress affects productivity and the chemical composition of crops. The variability of drought tolerance between species and cultivars of economically important crops, such as pepper (Capsicum species), requires specific investigations to understand the physiological and biochemical responses to the aftermath of drought. The fruits and leaves of four chilli pepper cultivars were investigated to elucidate the fruits’ pungency (Scoville Heat Units, SHU), ascorbic acid content, DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity, polyphenol content, membrane lipid peroxidation and key protective antioxidant enzyme activity under drought stress (18–28% volumetric water content) as compared to the control (35–60%). Drought increased the chilli pepper fruits’ pungency expressed in Scoville Heat Units (SHU) as well as ascorbic acid content, but this relationship was also dependent on genotype and stress duration. ‘Jolokia’ was marked as most sensitive to drought by increasing content of capsaicinoids and DPPH˙ scavenging activity under stress conditions. Capsaicinoids and Ascorbic acid (AsA) greatly influenced the antioxidant activity of highly pungent chilli pepper fruits, although total phenols played a significant role in the mildly pungent genotypes. Generally, the activities of antioxidant enzymes increased under drought in chilli pepper leaves and fruits, although the intensity of the reaction varied among the cultivars used in the current research. All the investigated biochemical parameters were involved in the drought response of chilli pepper plants, but their significance and effectiveness were highly cultivar-dependent.

Comparative Study of Nano-chitosan and Synthetic Bactericide Application on Chili Pepper (Capsicum annuum L.) Infected by Xanthomonas campestris

Nano-chitosan is considered as a prospective replacement for synthetic bactericides. In this study, the antibacterial activity of nano-chitosan and synthetic bactericides was compared in four chili pepper cultivars (Bianca, Lado, Kiyo, and Tanamo) infected by Xanthomonas campestris. To assess the effect of nano-chitosan and synthetic bactericide on the growth of the X. campestris-infected chili pepper plants, some parameters were observed including the plant height, number of leaves and chlorophyll content. It was shown that nano-chitosan was highly effective in controlling the pathogen infection on Bianca, Lado, and Tanamo, but not significant on Kiyo. The application of synthetic bactericide, however, was effective on Bianca and Lado, but not significant on Kiyo and Tanamo. It was also shown that the application of nano-chitosan can improve the growth of the X. campestris-infected chili pepper plants based on the significant difference on the plant height, number of leaves and chlorophyll content of cultivars tested, especially in Kiyo, Lado, and Tanamo. The application of synthetic bactericide, however, did not significantly improve the growth of the X. campestris-infected chili pepper plants. Nano-chitosan was shown to be effective in reducing the infection of X. campestris and potentially be used as an alternative to synthetic bactericide.

Virulence Phenotypes on Chili Pepper for Phytophthora capsici Isolates from Michoacán, Mexico

Phytophthora blight of vegetables caused by Phytophthora capsici causes significant economic losses in production of Solanaceae and Cucurbitaceae crops in Mexico. The development of universal resistant chili pepper cultivars is challenging due to the diverse virulence phenotypes produced by P. capsici. The objective of the study was to characterize the diversity of phenotypic interactions for P. capsici isolates recovered from production fields in Michoacán, Mexico, to facilitate the development of resistant cultivars. Virulence phenotypes were characterized for 12 isolates of P. capsici using 26 Capsicum annuum New Mexico Recombinant Inbred Lines (NMRILs) in greenhouse conditions. Criollo de Morelos CM-334 and California Wonder were used as resistant and susceptible controls, respectively. Seedlings at the four to eight true leaf stage were inoculated with 10,000 zoospores per seedling and disease severity was evaluated at 20 days post-inoculation. Two of the P. capsici isolates did not infect any pepper host even though the isolate was less than a year old. The 10 virulent isolates were designated in 10 virulence phenotypes. The information generated by this study is of utmost importance for efforts of producing resistant cultivars specific for Michoacán producers.