Bell Pepper Fruit Research Articles

Perspectives of Bell Pepper Breeding

SummaryThe Solanaceae family is the most important, representing a diverse group of different vegetables that are indispensable in every kitchen. Among the fruit vegetables, bell pepper has a specific identity. Bell pepper fruits are generally blocky, square, thick fleshed, three to four lobed and nonpungent. It is a versatile crop plant and its consumption is on the increase all over the world. With its increasing demand, world wide emphasis is being given to the development of hybrids. Flowers are bisexual borne in ones, twos or rarely in clusters at the apex of the main shoot as well as on the axils of the lateral branches. Many of the Capsicum varieties and hybrids are in the market. Considerable amount of heterosis is reported in this crop for many economical characters. Genetic and cytoplasmic male sterile systems are available in the crop. Chemical gametocides may compliment the use of male sterility in bell pepper for better hybridization. Micropropagation could be used for maintenance and multiplication of parental lines. Double haploids could be useful in fixing homozygosity of the population. In bell pepper, single cross hybrids are the only type of commercial hybrids. The hybrid seed yield is low but becomes economical as the seed price is relatively high. The hybrid seed is commonly produced by hand emasculation and hand pollination. Genetic and cytoplasmic male sterility is also being used but on a limited scale. Seed production required lot of care of the seed plot, timely inspection, proper crossing/hybridization, harvesting, seed extraction, drying, and storage.

Thaumatin‐like proteins – a new family of pollen and fruit allergens

Thaumatin‐like proteins – a new family of pollen and fruit allergens

Fruit Yield and Quality of Greenhouse-grown Bell Pepper as Influenced by Density, Container, and Trellis System

Production and quality of bell pepper (Capsicum annuum) fruit were evaluated in a passively ventilated greenhouse, in soilless media trellised to a “V” system (two-stempruned plants) or the “Spanish” system (nonpruned plants) in flat bags or nursery pot containers; and densities of 1.5, 1.9, 3.0, and 3.8 plants/m2 (0.14, 0.18, 0.28, and 0.35 plants/ft2), in a winter-to-summer-crop in Gainesville, Fla. The trellis systems did not affect total marketable fruit yields but production of extra-large fruit was higher (38%) in non-pruned than in pruned plants. Marketable fruit yields were similar in plants grown in bags and pots, and had positive linear responses to increased plant density. Not pruning reduced by half the percentage of fruit with blossom-end rot. Pruned plants produced 50% fewer flower bud supporting nodes than non-pruned plants but had a greater percentage of fruit set. Regardless of trellis systems, fruit set per plant decreased linearly as plant density increased. Overall, the “Spanish” trellis system at a density of 3.8 plants/m2 resulted in greater yields of extra-large fruit and required 75% less labor than the “V” system to prune and support the plant canopy.

Diphenylamine Inhibits Respiration of Green Bell Peppers

The mechanism by which diphenylamine (DPA) controls superficial scald in apples and reduces chilling injury in green bell peppers [Capsicum annuum L. var. annuum (Grossum Group)] has been assumed to be related to its antioxidant activity. In the present study, DPA inhibited the respiratory activity of green bell pepper fruit as well as oxygen uptake by the mitochondria isolated from them. When the alternative oxidase was inhibited with n-propyl gallate or disulfiram during state 4 respiration, DPA did not further inhibit O2 uptake. Treating green bell peppers with DPA before storage did not alter the induction and abundance of the alternative oxidase protein in mitochondria which was maximally induced in peppers stored at 4 °C. Whether added before or after the uncoupler, 2,4-dinitrophenol, DPA negated the enhanced O2 uptake associated with uncoupling of electron transfer in isolated mitochondria. These observations indicate that DPA inhibits the flow of electrons through the cytochrome path, probably somewhere in the cytochrome bc1 complex. Although the secondary amine function of DPA makes it a powerful antioxidant, the effectiveness of DPA in reducing chilling injury in green bell peppers and superficial scald in apples [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.] also may be due, in part, to its inhibition of respiration.

Cloning and Molecular and Immunological Characterisation of Two New Food Allergens, Cap a 2 and Lyc e 1, Profilins from Bell Pepper (Capsicum annuum) and Tomato (Lycopersicon esculentum)

Background: Profilins are recognised by IgE of about 20% of patients allergic to birch pollen and plant foods. They are ubiquitous intracellular proteins highly cross-reactive among plant species. Therefore, they were called panallergens and are made responsible for cross-sensitisation between plant pollen and food. Objectives: The aim of the present study was to clone the cDNAs encoding profilins from bell pepper and tomato, to produce and purify the recombinant proteins and to compare their IgE-binding capacities to those of the natural proteins. Methods: cDNA clones coding for profilin were obtained by RT-PCR from total RNA of tomato and bell pepper fruits, sequenced and expressed as non-fusion proteins in Escherichia coli. The recombinant profilins were subsequently purified and tested for IgE-binding and inhibition capacity with sera from 34 food-allergic patients. Possible oligomerisation of recombinant profilins was investigated by HPLC analysis and its influence on IgE binding assayed by ELISA. Results: The open reading frame from both profilins encompasses 393 bp with a predicted molecular mass of 14,184 kD and a pI of 4.44 for bell pepper profilin (Cap a 2) and 14,257 kD and a pI of 4.46 for the profilin from tomato (Lyc e 1). The two protein sequences display 91% identity, whereas tomato profilin from pollen shares only 75% identity with tomato fruit profilin. Eleven out of 34 food-allergic patients (32%) display IgE binding to both purified profilins. Preincubation of a serum pool with either purified rCap a 2 or rLyc e 1 nearly abolished IgE binding to natural Cap a 2 and Lyc e 1, respectively. In addition, purified recombinant Cap a 2 was able to inhibit IgE-binding to rLyc e 1 by approximately 50%, whereas rLyc e 1 completely blocked IgE-binding to rCap a 2 in cross-inhibition assays. HPLC analysis showed that in solution Cap a 2 and Lyc e 1 can be found predominantly as dimers, which can be partially reduced to monomers by addition of dithiothreitol (DTT). In ELISA DTT-treated Lyc e 1 displayed a clearly lower IgE-binding capacity than untreated profilin. Conclusions: Purified rCap a 2 and rLyc e 1 proved to be valuable tools for studying cross-reactivity to profilins in patients allergic to pollen and food.

A Simple Model for Rapid and Nondestructive Estimation of Bell Pepper Fruit Volume

Nondestructive estimates of fruit volume are used for yield prediction. They are also used to study the relationship between fruit expansion rate and susceptibility to diseases or physiological disorders such as fruit cracking. A model relating bell pepper (Capsicum annuum) fruit diameter and length to its volume was derived using the equation of the volume of a sphere as the starting point. The model has the following formula: VF = KD2 Lπ/6, where VF is fruit volume, K is the shape factor that varies with fruit type, D is fruit diameter, and L is fruit length. The model is simple, easy to use in the field, and may account for variations in fruit shape. Regression analyses using actual fruit volume of bell pepper measured with the water displacement method and the volume estimated using different equations showed that accuracy of the new model is comparable to that of one of the best models previously proposed. However, because the model is less complex than previous models, it is easier to use in the field.

Effect of pressure and blanching treatments on endogenous enzymatic activity and vitamin C content of bell pepper fruit

The effect of high pressure and blanching treatments on green bell pepper was studied. Both processes caused changes on pectin methylesterase activity and vitamin C and protein contents. Polygalacturonase activity was not detected in any of the samples studied. There seems to be no significant difference caused by both types of processing.

Diphenylamine reduces chilling injury of green bell pepper fruit

Diphenylamine (DPA), an antioxidant widely used to control superficial scald in apples stored at low temperatures, reduced the chilling-induced pitting of green bell pepper (Capsicum annuum L.) fruit in a concentration-dependent manner up to 12 mM. Treatment was effective whether applied as a 2-min dip or injected into the seed cavity prior to storing peppers at 1° C for 6 or 8 days followed by storage at 20° C for an additional 2 days. Ethanol (5%), the solvent used to dissolve the diphenylamine, also reduced chilling injury of green bell peppers, but to a lesser extent than DPA. Changes in all of the chlorophyll fluorescence parameters were observed within 24 h following the exposure of green bell peppers to low temperatures, whereas visible manifestation of chilling injury was not observed until after the peppers had been exposed to several days of low temperatures. Diphenylamine reduced the chilling-induced decline in maximal chlorophyll fluorescence and increased the time taken for maximal chlorophyll fluorescence to occur and the size of the electron acceptor pool. If chilling injury results from oxidative stress induced by low storage temperatures, it is unlikely that chloroplasts were the site of production of active oxygen species in these green bell peppers since they were stored in the dark. The rapidity of chlorophyll fluorescence responses to low temperatures makes chlorophyll fluorescence analysis useful to distinguish between chilling-sensitive and chilling-resistant plant tissues, but does not measure the extent of chilling injury.

Regulation of ethanolic fermentation in bell pepper fruit under low oxygen stress

Abstract Bell pepper fruit were stored under a continuous flow of 0 and 1% O 2 (balance N 2 ) or air for 7 days at 20 °C to study the regulation of ethanolic fermentation. The concentrations of ethanol and acetaldehyde were very low during storage at 1% O 2 and air. At 0% O 2 , ethanol and to a lesser extent acetaldehyde, rapidly accumulated in the tissue. Pyruvate decarboxylase (PDC) activity greatly increased in fruit exposed to 1% O 2 , while activity in fruit exposed to 0% was only slightly higher than that of the control. Alcohol dehydrogenase (ADH) activity greatly increased in fruit exposed to 1% but at 0% O 2 was at the same level as the control. The activity of ADH was about 10 times that of PDC during storage. Changes in ADH isozymes correlated well with changes in ADH activity. Concentration of NADH did not change during storage in air, but in fruit in 0 and 1% O 2 showed a significant increase. Concentrations of pyruvate were very low and did not change during storage at 1% O 2 and air. At 0% O 2 , pyruvate rapidly accumulated in the tissue. The K m of ADH in bell pepper fruit was 0.74 mM for acetaldehyde, and 0.33 mM for NADH. The K m of PDC in bell pepper fruit was 0.92 mM for pyruvate. Possible regulation of ethanolic fermentation is briefly considered.

Ascorbic Acid Content in Relation to Ascorbic Acid Oxidase Activity and Polyamine Content in Tomato and Bell Pepper Fruits During Development, Maturation and Senescence

Tomato (Lycopersicum esculentum Mill, cv. XPH-1251) and bell pepper (Capsicum annuum, cv. New ace) plants were grown in a greenhouse in controlled hydroponic conditions, and fruits were harvested at different intervals from 18 to 94 days from fruit set. Total ascorbic acid was higher in bell pepper than in tomato fruit. In pepper fruit, the level increased rapidly during its development, reaching a maximum of 136.1 mg/100 g at 51 days from fruit set and then decreased suddenly, reaching a minimum of 65.5 mg/100 g at 64 days. Ascorbic acid in tomato fruit increased slowly reaching a maximum of 94.9 mg/100 g at 74 days and then declined slowly. The decrease in ascorbic acid coincided with the initiation of ripening, as indicated by color change, and with an increase in the activity of ascorbate oxidase. There was more putrescine in bell pepper than in tomato fruit. No major changes were observed in spermine and spermidine in bell pepper and in spermidine in tomato fruits. However, putrescine in bell pepper fruit and spermine in tomato fruit increased very early until about 30–38 days and then decreased. We conclude that ascorbic acid decreases in tomato and bell pepper fruits after 74 and 51 days, respectively, and this decrease coincided with an increase in ascorbate oxidose, as well as a decrease in putrescine in pepper and spermine in tomato fruit.

Isolation and spectroscopic characterization of a recombinant bell pepper hydroperoxide lyase

Fatty acid hydroperoxide (HPO) lyase is a component of the oxylipin pathway and holds a central role in elicited plant defense. HPO lyase from bell pepper has been identified as a heme protein which shares 40% homology with allene oxide synthase, a cytochrome P450 (CYP74A). HPO lyase of immature bell pepper fruits was expressed in Escherichia coli and the enzyme was purified and characterized by spectroscopic techniques. The electronic structure and ligand coordination properties of the heme were investigated by using a series of exogenous ligands. The various complexes were characterized by using UV-visible absorption and electron paramagnetic resonance spectroscopy. The spectroscopic data demonstrated that the isolated recombinant HPO lyase has a pentacoordinate, high-spin heme with thiolate ligation. Addition of the neutral ligand imidazole or the anionic ligand cyanide results in the formation of hexacoordinate adducts that retain thiolate ligation. The striking similarities between both the ferric and ferrous HPO lyase–NO complexes with the analogous P450 complexes, suggest that the active sites of HPO lyase and P450 share common structural features.

Fruit-developmental regulation of bell pepper knolle gene ( cakn) expression

A cDNA, cakn, orthologous to the Arabidopsis KN gene, which is involved in vesicle fusion during cell plate formation, was isolated from bell pepper fruit. cakn seems to be monogenic and its expression mainly transcriptionally regulated. During fruit development, transcript and protein levels increase significantly in the early stages in which numerous cell divisions occur, but in the stages corresponding to fruit growth by cell enlargement, whereas the messengers are undetectable, proteins are still faintly present, suggesting a different stability rate for the two types of macromolecules.

Ethanolic Fermentation Enzymes, their Products and Transcription of Alcohol Dehydrogenase from Bell Pepper Fruit Held under Various Low Oxygen Atmospheres.

The concentrations of ethanol and acetaldehyde in bell pepper fruit were very low during storage at 1%, 3%, 5%, and 10% O2, and air at 20°C. At 0% O2, ethanol and acetaldehyde to a lesser extent, rapidly accumulated in its tissue. The activity of alcohol dehydrogenase (ADH) was about 10 times that of pyruvate decarboxylase (PDC) during storage. The ADH activity greatly increased in the fruit exposed to 1% and 3% O2, but in those exposed to 0%, 5%, and 10% O2 it was slightly higher than that of the control. The PDC activity greatly increased in the fruit exposed to 1%, 3%, and 5% O2, while those of fruits exposed to 0% and 10% O2 were slightly higher than that of the control. ADH transcripts in the fruit exposed to 5% and 10% O2 or air were not detectable, whereas those in the fruit exposed to 1% O2 were significantly higher than those in 0% and 3% O2 on day 1 at 20°C. The discrepancy of the enzyme activities and their product levels are discussed.

Effects of climatic factors and water stress on the diurnal ¯uctuation in diameter of bell pepper fruit

SummaryCracking of bell pepper fruits is one of the most severe problems affecting their marketable yield. Repeated shrinkage and expansion weakens the fruit cuticle and causes cracking. This study investigated the effects of climatic factors and water stress on the diurnal fluctuation in pepper fruit diameter. Two experiments were conducted in three controlled greenhouses with different air temperatures and relative humidities. The results indicated that the factors affecting leaf transpiration, such as solar radiation, vapour pressure deficit (VPD), air temperature and water stress, affect the timing and amplitude of diurnal fluctuations in diameter of bell pepper fruit. Earlier fruit shrinkage start time (FSST) in the morning, earlier fruit shrinkage ending time (FSET) in the afternoon and larger shrinkage amount were observed in fruits grown in the greenhouse with high night air temperature and low night vapour pressure deficit. Plant root water stress resulted in earlier FSST. Higher incoming radiation increased fruit shrinkage. Sunlit fruits shrank more than those in shade under the same environmental conditions, which is a possible mechanism for more cracking in sunlit fruits. However, no differences of FSST and FSET were observed between fruits in sun and in shade.

508 Ascorbic Acid Content in Tomato and Bell Pepper Fruit during Development, Maturation, and Senescence on the Plant and Relation with Ascorbate Oxidase and Polyamines

Plants were grown in a greenhouse in controlled hydroponic conditions, and fruit were harvested at different intervals from 18 to 94 days from fruit set (DFFS). AsA was higher in pepper than in tomato fruit. In pepper fruit, it increased very fast and reached a maximum at 50 DFFS and then decreased suddenly and reached a minimum about 60 DFFS. AsA in tomato fruit increased slowly and reached a maximum after about 75 DFFS and then declined slowly. The decrease in AsA is correlated with the initiation of ripening and with an increase in the activity of AAO. There was more putrescine in pepper than in tomato fruit. There were no major changes in spermine and spermidine in pepper and spermidine in tomato fruit. However, putrescine in pepper fruit and spermine in tomato fruit increased very early until about 30 to 38 DFFS and then decreased in a manner similar to the decrease in AsA. Putrescine in tomato fruit increased consistently and did not decrease even during the senescence of the fruit. We conclude that AsA decreases in tomato and pepper fruit after 75 and 50 DFFS, respectively, and this decrease is related to an increase in AAO and a decrease in putrescine in pepper and spermine in tomato fruit.

Environmental factors affecting the cracking of greenhouse-grown bell pepper fruit

SummaryThe cracking of bell pepper fruit is one of the main physiological disorders that reduce marketable yield. Understanding the environmental and endogenous factors that influence this disorder may help to reduce its severity. Plants grown in three greenhouses were subjected to differing potential transpiration (Tp) at night, with identical daytime Tp. Measurements included climatic variables in the greenhouses, soil water content, sap flow, transpiration, leaf temperature, surface and internal fruit temperatures, fruit and stem diameters, stomatal conductance, and leaf area. The results show that at night pepper plants transpired at a rate proportional to the vapour pressure difference (leaves to air; VDPla) in the respective greenhouses. The percentage of cracked fruits was highest in the greenhouse with the lowest night vapour pressure deficit (VPD) and lowest in the greenhouse with the highest VPD. Both increased direct radiation reaching the fruit surface and decreased soil water content reduced the growth rate of the fruit. Direct radiation and the temperature of the fruit inner space were well correlated with diurnal expansion and shrinkage of the fruit. The fruits with the higher expansion-shrinkage amplitude had more severe cracking symptoms. Decreased soil water potential counteracted the negative effect of direct radiation. These results indicate that the water status of the fruit is a key factor in determining the severity of fruit cracking. The implications of these results for greenhouse management in pepper production are discussed.

Cuticular cracking in bell pepper fruit: II. Effects of fruit water relations and fruit expansion

SummaryThe objective of this research was to study the role of fruit expansion and turgor in the formation of cuticular cracking in bell pepper (Capsicum annuum L.). Fruit was artificially cracked by filling detached hollowed pepper fruits with distilled water. However, when isotonic mannitol solution was used, cracking did not occur. Similarly, immersion of intact red fruits in tap water caused formation of cuticular cracks following a delay of 30 h during which the turgor potential of the red pericarp and the expansion of the fruit diameter increased to critical threshold values of 0.65 MPa and 1±2%, respectively. On the other hand, in the greenhouse, attached red fruits underwent diameter change of only 0.2% and, when most expanded, the fruit had a turgor potential of only 0.3 MPa. In greenhouse grown plants, pepper fruits become susceptible to cracking at the stage of colour turning, a stage at which they also become susceptible to artificially induced cracking by immersion in water. Under greenhouse conditions both young and mature fruits exhibited growth independent of diurnal diameter fluctuations. Larger diameter fluctuations were observed in mature fruit, under conditions which encouraged cracking. Based on these results, we suggest that it is the magnitude of the diurnal fluctuations in fruit turgor and diameter, continuing over a long period which may cause the splitting of the cuticle.

Interference of Purple Nutsedge (Cyperus rotundus) Population Densities on Bell Pepper (Capsicum annuum) Yield as Influenced by Nitrogen

Additive series studies were conducted under greenhouse conditions to determine the effects of nitrogen (N) rate and purple nutsedge densities on the yield of ‘California Wonder’ bell pepper. Initial densities of purple nutsedge were 0, 100, 200, and 300 plants/m2. Nitrogen was applied at 70, 140, and 210 kg/ha. Plants were allowed to interfere for 10 wk. There were significant purple nutsedge population density by N rate interactions on bell pepper fruit yield. At 70 kg N/ha, no significant effect of weed population densities was found on fruit yield, whereas at the rates of 140 and 210 kg N/ha there were significant nutsedge density effects. As N rates and nutsedge densities increased, so did purple nutsedge biomass. Linear regression models described the interference. Bell pepper fruit yield reduction was 73% at 210 kg N/ha with an initial nutsedge population density of 300 plants/m2.

The Effects of American Black Nightshade (Solanum americanum) Interference in Bell Pepper (Capsicum annuum)

Information about the effects of weed interference on crop yields can help growers make appropriate management decisions. Such information is particularly useful in horticultural crops such as pepper, where the number of registered herbicides is limited. Bell pepper is the second most-valuable vegetable crop grown in Florida, and American black nightshade (Solanum americanum) is one of the primary weeds in Florida pepper production. Additive experiments were conducted in 1997 in Florida to determine the effects of American black nightshade interference on bell pepper yield. One additive experiment was conducted in Gainesville, Fla., in the spring and two additive studies were conducted in the fall in Gainesville and Live Oak, Fla. A randomized complete-block design with four replications was used. Double rows of `Capistrano' peppers were transplanted into white polyethylene mulched beds with 1.22-m centers. Peppers were planted at an in-row spacing of 0.3 m. Weeds were propagated in the greenhouse in polystyrene flats and transplanted at the two-leaf stage simultaneously with the peppers. Overhead irrigation was used and monitored with tensiometers. Fertilizers and pesticides were applied based on Extension recommendations. Weed densities in the spring trial were 0, 2, 4, 8, 12, 16, and 20 plants/m2. Weed densities of 0, 0.5, 1, 1.5, 2, 3, 4, and 8 plants/m2 were planted in the fall. Crop and weed heights were recorded weekly, and fruit number, grade, and weights were recorded at each harvest. Crop and weed dry weights were obtained at final harvest. Data were subjected to analysis of variance and regression. There was an interaction by season, but there was not an interaction by location for the fall season; therefore, the fall data were combined. In all trials, S. americanum had a significant effect of bell pepper fruit yield. In the spring, the biological threshold of weed interference occurred at a density of four S. americanum/m2, but only caused a 50% yield loss. In the spring, the critical density causing 20% yield loss was calculated from the regression model to occur at 0.36 S. americanum/m2. A calculated density of 0.58 S. americanum/m2 caused 20% yield loss in the fall. Plant height and dry weight data indicated that the pepper initially grew more quickly in the fall than in the spring.

Yield and Fruit Quality of Pepper (Capsicum annuum L.) in Response to Bioregulators

To test the effectiveness of different bioregulators in enhancing bell pepper (Capsicum annuum L.) yield and fruit quality, the commercial bioregulators CCC, NAA, GA3, and Biozyme® were sprayed on plants at flower initiation, followed by two additional applications at 30-day intervals. Biozyme produced a significant increase in total yield but ≈40% of the fruit were not marketable. Treatment with NAA produced the highest yield of marketable fruit. Treatments did not affect fruit firmness compared to the control. Gibberellic acid increased fruit ascorbic acid and citric acid concentrations and Biozyme, GA3, and CCC increased fruit soluble solids content. Biozyme treatment increased fruit fructose, sucrose, carotenoid, and lycopene concentration. Treatments had no effect on fruit calcium concentration or pH. Chemical names used: chlormequat chloride (CCC); naphthaleneacetic acid (NAA), gibberellic acid (GA3); GA3 + IAA (indoIe-3-acetic acid) + zeatine + micronutrients (Biozyme®).