Basil Cultivars Research Articles

Detection of the Downy Mildew Pathogen on Seed of Basil Following Field Infection in Southern New Jersey

Different basils (Ocimum sp.) and cultivars (28 in 2009 and 32 in 2010) were evaluated for susceptibility to basil downy mildew (Peronospora belbahrii) at the Rutgers Agricultural Research and Extension Center near Bridgeton in southern New Jersey. At the end of each growing season, seed was collected from individual plants and stored for potential downy mildew pathogen detection using real-time polymerase chain reaction (PCR) analysis. Most of the basil cultivars and breeding lines were showing symptoms of basil downy mildew infection at the time of seed collection before the first frost near the end of the production season. Symptoms of basil downy mildew were present on 25 of the 28 (89%) basil lines evaluated in 2009 and 26 of 32 (81%) basil lines tested in 2010 at the time of seed harvest, with sporulation evident on the abaxial surface of infected leaves. Real-time PCR analysis of seed collected from various infected plants detected P. belbahrii on seed of 14 of 25 (56%) basil lines tested in 2009 and 8 of 32 (25%) tested in 2010. Importantly, P. belbahrii was not only detected on seed of sweet basil (Ocimum basilicum) phenotypes but also on seed of ‘Spice’ basil (Ocimum americanum) in 2009 and ‘Sweet Dani Lemon Basil’ basil (Ocimum citriodorum), ‘Holy Red and Green’ basil [Ocimum tenuiflorum (form. sanctum)], ‘Lime’ basil (O. americanum), and again on ‘Spice’ basil in 2010 where no symptoms (i.e., no chlorosis or sporulation) were present on the leaves when seed were collected. This work demonstrates that basil seed, regardless of basil species and whether symptoms are visible on foliage of the basil plant or the plant is immune or resistant to downy mildew, can test positive for the presence of P. belbahrii using a real-time PCR assay following exposure of plants to the pathogen during the natural development of downy mildew under field conditions.

A qPCR approach to quantify the growth of basil downy mildew pathogen Peronospora belbahrii during infection

Sweet basil (Ocimum basilicum) is an economically important herb crop. Its production has been severely threatened by the downy mildew disease caused by the obligate biotrophic oomycete Peronospora belbahrii. Deployment of disease resistant cultivars would be the most cost effective, environmentally friendly control strategy. However, transferring resistance found only in wild Ocimum species to sweet basil via traditional breeding has been extremely challenging. To apply cutting-edge biotechnological approaches to breeding for basil downy mildew resistance, it is essential to better understand the molecular basis of basil-P. belbahrii interactions, for which a set of experimental tools, including a sensitive disease assessment method, are required. Here we described a quantitative PCR (qPCR) approach to quantify P. belbahrri growth during infection. The approach utilizes two pairs of primers that specifically and effectively amplify the internal transcribed spacer 2 (ITS2) region of P. belbahrii and basil β-tubulin gene for pathogen detection, and normalization of pathogen DNA relative to plant biomass, respectively. This approach was shown to be able to detect increased pathogen growth during infection time course and differentiate disease levels of different sweet basil cultivars at an early infection stage. This qPCR approach is expected to facilitate the dissection of the molecular basis of basil-P. belbahrii interactions and it can also be used for pathogen detection in propagating materials to ensure the growth of disease-free materials and prevent disease spread.

The Effect of Organic and Chemical Nitrogen Fertilizers on the Yield and Qualitative Characteristics of Two Basil Cultivars

The Effect of Organic and Chemical Nitrogen Fertilizers on the Yield and Qualitative Characteristics of Two Basil Cultivars

Fertilization modifies the essential oil and physiology of basil varieties

Medicinal and aromatic crops are economically important because they are sources for secondary metabolites such as essential oils (EOs) and polyphenolic compounds. High biomass yields are obtained by conventional chemical fertilizers, whereas the production of EOs is more influenced by elicitors that act on secondary metabolic pathways. The objective of the field trials was to evaluate the effects of biologic and conventional fertilizers (biosolids: 40 and 20 t ha−1, organic: 600 kg ha−1, microorganisms (arbuscular mycorrhizal fungi, AMF): 60 kg ha−1, chemical NPK 20-20-20: 300 kg ha−1) on plant growth, EO chemical profile and yield, and physiology of sweet basil (Ocimum basilicum L.). The two sweet basil cultivars (varieties) used were the green-leafed ‘Aromat de Buzau’ and the purple-leafed ‘Violet de Buzau’. The greatest increases in fresh yields compared with unfertilized plants, 116% and 68% increases for the ‘Aromat de Buzau’ and ‘Violet de Buzau, respectively, were obtained from the conventionally (chemical) fertilized plants. The 40 t ha−1 biosolids treatment increased the EO content of the ‘Aromat de Buzau’ by 30%, while the AMF and organic treatments increased the EO content of the ‘Violet de Buzau’ by 21%. The major constituents of ‘Aromat de Buzau’, methyl chavicol and β-linalool, were increased by 4 and 17% with the AMF and organic treatments, respectively. Eucalyptol and δ-guaiene concentrations in the EO were higher in the 40 t ha−1 biosolids treatment, while τ-cadinol and γ-cadinene were higher in the 20 t ha−1 biosolids treatment. For ‘Violet de Buzau’, the AMF treatment led to an increase of β-linalool, limonene, and (+)-camphor, and decreased the concentration of methyl chavicol. The organic treatment increased the concentrations of limonene, (+)-camphor, terpinene-4-ol, and β-caryophyllene, and decreased the concentration of methyl chavicol. The highest concentration of methyl chavicol was observed in the chemical fertilizer treatment. The 20 and 40 t ha−1 biosolids treatments led to highest yields of eucalyptol, (+)-camphor, terpinene-4-ol, β-caryophyllene, germacrene D, and τ-cadinol. The results demonstrated that conventional fertilizers can increase fresh yield while biological fertilizers positively alter the EO composition, leading to increased crop quality.

Methyl jasmonate effects on volatile oil compounds and antioxidant activity of leaf extract of two basil cultivars under salinity stress

Basil (Ocimum basilicum L.) as an economic and culinary herb is used in traditional medicine. In this research, a pot experiment was conducted, as factorial based on randomized completely design with three replications, to examine the influence of methyl jasmonate (MeJA) on volatile substances and chemical components as well as antioxidant activity of leaf’s extract from two commercial cultivars (Genove and Rubi) of sweet basil under salinity stress. The treatments were comprised MeJA (0 and 0.5 mM) and salinity stresses (0, 30, 60, and 90 mM). Using MeJA foliarly meaningfully raised the essential oil content in the Rubi cultivar at 0 and 30 mM of salinity and in the Genove cultivar just on 30 mM of salinity. MeJA treatment increased the essential oil content and also showed noticeable effects on the main components of the oils. The foliar application of MeJA raised the percentages of linalool and 1,8-cineole, whereas reduced the percentages of α-cadinol, α-bergamotene, β-maaliene, and eugenol in the extracted oil. In both basil cultivars, the MeJA significantly enhanced the antioxidant activity. The highest antioxidant activities in the Rubi and Genove cultivars were obtained at 0 mM (control) and 60 mM of salinity with the MeJA application, respectively. In conclusion, the foliar application of MeJA caused to different responses in the cultivars and reduced the negative effects of salt stress.

Phenotypic and genotypic characterization of basil hybrids and cultivars

Phenotypic and genotypic characterization of basil hybrids and cultivars

Cropping season affect the performance of basil cultivars and hybrids

Cropping season affect the performance of basil cultivars and hybrids

Organic vertical gardening for urban communities

As the world's population continues to increase, other methods of production are being sought after that can help conserve water and save land especially in urban communities. Vertical gardening is a technique by which plants can be grown in a vertical structure without soil, to obtain a maximum possible yield within a particular space indoors or outdoors. Organic vertical gardening is carried out without the application of synthetic chemicals and fertilizers, following the standards and approved inputs of the National Organic Program (NOP). Currently, there is a conflict on the relationship between organic vertical gardens and organic farming practices between urban growers due to the cultivation of plants without soil in the latter. Little to know studies have been done on organic vertical farms as of date. Several cultivars of lettuce, chard, kale, mustard-green, basil and coriander grown in the verti-grow system and were harvested successfully. Automated system called 'Drip Organics' provided organic nutrients to the plants. Perlite and coco fiber media was used in the stacked pots. Although modern organic farming would remain a widely food production method as evidenced by its global acceptance and steady growth, organic vertical farming has a potential to provide food security, year-round produce and ease transportation of food within urban and semi urban areas. This article discussed cultivar trials in organic vertical system on the certified organic farm of the Tennessee State University, Nashville.

ANTHOCYANINS OF BASIL LEAVES: DETERMINATION AND PREPARATION OF DRIED ENCAPSULATED FORMS

Anthocyanins composition of five purple leaves cultivars of Ocimum basilicum L. was investigated by reversed-phase HPLC with mass-spectrometric detection in the conditions of ions partial fragmentation as well as preparation of dried differently colored forms of anthocyanins encapsulated into maltodextrin matrix. Mass-spectra analysis revealed that according to anthocyanin set basil cultivars under investigation may be divided onto two groups with common feature being high level of acylation with (mainly) p-coumaric, ferulic and malonic acids of the same base – cyanidin-3-dihexoside-5-hexoside. The presence of acylation with substituted cinnamic acids permits to obtain solutions not only with red color (the property of the flavylium form) but also with blue shades coloration due to quinoid and negatively charged quinoid forms. All forms exept of flavylium are not stable in solution but stable enough to prepare dried encapsulated forms by lyophilization. And thou the loss of anthocyanins at drying is not negligible the final product is characterized with high stability at storage in refrigerator.

Germination test and ornamental potential of different basil cultivars (Ocimum spp.)

Basil (Ocimum spp.) is an essential oil producing plant and it is used as a condiment for diferent foods, besides serving as raw material for medicinal purposes. This crop has also been showing great importance as an ornamental plant in recent years. However, basil lacks studies concerning its different usages with special regards to its ornamental potential. Therefore, this study aimed at evaluating the vegetative development and the ornamental potential of the basil cultivars ‘Grecco a Palla’ (O. minimum), ‘Alfavaca Basilicão Vermelho’ (O. basilicum), and ‘Thai Basil’ (O. basilicum), under protected cultivation. The following characteristics were evaluated: germination percentage, germination speed index, plant canopy diameter (cm), leaf and inflorescence length (cm), plant height (cm), and fresh and dry leaf mass (g). The ornamental potential was estimated based on visual evaluations of plant canopy volume; leaf shape, texture, size, and color; stem and flower color; and number of days to flowering. Cultivar ‘Thai Basil’ presented the highest leaf dry mass and ‘Grecco a Palla’ showed the highest germination speed index and seed germination percentage. All cultivars bloomed within 60 days after planting and exhibited color and brightness variability, which are desirable traits for a landscape composition. ‘Grecco a Palla’ stood out for its short and compact inflorescences, dwarf size and globular shape when grown as a potted plant. The studied cultivars demonstrated favorable characteristics for ornamental usage based on visual assessments.

Regulation of early growth and antioxidant defense mechanism of sweet basil seedlings in response to nutrition

Basil cultivars are among most used crops worldwide, but high level of morpho-physiological variations is mainly due to the cultivation characteristics. The present study aimed to investigate the physiological changes and the accumulation of secondary metabolites as a response to prolonged nutrient deprivation in shoots and roots of sweet basil (Ocimum basilicum L. var. minimum). Sweet basil seedlings were grown in media with quarter, half and full strength of micro and macronutrients under different levels of KNO3 alone or in combination with different levels of NH4NO3. Evaluated parameters included characteristics of germination, development of leaves, content of photosynthetic pigments and responses of different parameters related to oxidative stress. While the early growth is influenced mainly due to NH4NO3 presence, all the levels of nutrient supply were found to trigger and maintain the antioxidant defence system of sweet basil seedlings. With the variations among seedling parts, the ammonium nutrition was notably enhanced levels of activity of SOD, CAT, A-POX, G-POX and P-POX, but had no effect on total antioxidant activity and total phenolic content, including flavonoids, which is mainly accumulated in nutrient deprived roots. In addition, phenylalanine ammonia-lyase activity was analysed and potential pathways of secondary metabolites synthesis were discussed. The enzymatic and non-enzymatic system in O. basilicum var. minimum seedlings was capable to reverse the stress conditions during growth under nutrient deprivation.

Effect of seed sowing period on polyphenolic compounds content in basil (Ocimum basilicum L.) under greenhouse conditions

The object of the research is the process of formation of the polyphenolic complex by basil plants. The complexity in evaluating the process of polyphenols accumulation lies in the fact that the formation of these compounds occurs under the influence of a number of biotic and abiotic factors, leading to variation in the level of polyphenols in a very wide range even for plants of the same cultivar.The influence of different seed sowing periods of five cultivars of basil on the accumulation of polyphenolic compounds in each cutting of green mass was investigated. The obtained data were mathematically computed using AgrostatNew and MicrosoftExcel software. It was found that cultivars with purple coloration of leaves accumulate by 51.2–66.6 % more polyphenols than green cultivars. It was observed that in the green cultivars Bad’oryi, Rutan and Siaivo, the level of polyphenols increases with each subsequent cutting of green mass during the February and April seed sowing periods. The cultivars with purple coloration of leaves have shown the highest level of accumulated polyphenols in the first cutting for the February seed sowing period and in the fourth and fifth cutting in April. The level of polyphenols in all the cultivars, which were sown in March, did not significantly change during cutting, indicating the optimal cultivation conditions.

Water deficit stress fluctuates expression profiles of 4Cl, C3H, COMT, CVOMT and EOMT genes involved in the biosynthetic pathway of volatile phenylpropanoids alongside accumulation of methylchavicol and methyleugenol in different Iranian cultivars of basil

Here, for the first time, the accumulation ratio of methylchavicol and methyleugenoland compounds together with the expression profiles of five critical genes (i.e., 4Cl, C3H, COMT, CVOMT and EOMT) in three Iranian cultivars of basil were assessed under water deficit stress at flowering stage. The highest value of methylchavicol was detected for Cul. 3 under severe stress (S3; 7.695μg/mg) alongside Cul. 2 under similar circumstances (S3; 4.133μg/mg), while regarding Cul. 1, no detectable amounts were acquired. Considering methyleugenol, Cul. 3 (0.396μg/mg; S0) followed by Cul. 1 (S3; 0.160μg/mg) were the capable plant samples in producing some detectable amounts of methyleugenol. Apart from some expectations, all the genes under study exhibited also different transcription ratios under deficit stress. Our results, overall, demonstrated that the regulation of the above-mentioned genes and production of methychavicol and methyleugenol seems to be a cultivar- and drought stress-dependent mechanism.

Changes in antioxidant enzyme activity in response to salinity-induced oxidative stress during early growth of sweet basil

Sweet basil is one of the most widely used commercially cultivated plants worldwide. Here, we investigated the early growth and antioxidant enzyme activity of salt-stressed sweet basil seedlings. We subjected in vitro-grown sweet basil (Ocimum basilicum L. var. minimum) to different levels of sodium chloride (0, 10, 20 and 30 mM) and collected data per week during the first month of growth. The responses of antioxidant enzymes to salt stress were variable. Superoxide dismutase (SOD) exhibited similar patterns of increasing and decreasing activity in both shoots and root. By contrast, pyrogallol peroxidase (PPOX) and guaiacol peroxidase (GPOX) activity increased during plant growth but varied among seedling parts. Catalase (CAT) was the most salinity-sensitive enzyme examined, with activities varying depending on the plant part and stage of development. Our results also suggest that nutrient uptake is inhibited in basil under salt stress and that antioxidative defence mechanisms are induced in salinity-stressed sweet basil during early development. The changes in nonspecific antioxidant biomarkers observed in this study could be highly valuable for studying the mechanism underlying stress tolerance in O. basilicum L. var. minimum and could facilitate the development of tolerant basil cultivars.

Changes in visual quality, physiological and biochemical parameters assessed during the postharvest storage at chilling or non-chilling temperatures of three sweet basil (Ocimum basilicum L.) cultivars.

Leaves of three different sweet basil (Ocimum basilicum L.) cultivars (Italico a foglia larga, Cammeo, and Italiano classico) packed in macro-perforated polyethylene bags were stored at chilling (4°C) or non-chilling temperature (12°C) for 9days. During storage, visual quality, physiological (respiration rate, ethylene production, ammonium content) and chemical (antioxidant activity, total polyphenols and polyphenol profile) parameters were measured. Detached leaves stored at chilling temperature showed visual symptoms related to chilling injury, while ethylene production and ammonium content resulted associated to cultivar sensibility to damage at low temperature. Storage at 4°C caused a depletion in polyphenols content and antioxidant capability, which was preserved at 12°C. Regarding the polyphenols profile, stressful storage conditions did not enhance the phenolic metabolism. However, leaves stored at 12°C did not loss a significant amount of metabolites respect to fresh leaves, suggesting the possibility to extend the storability after the expiration date, for a possible recovery of bioactive compounds.

Chemical composition and some biological activities of the essential oils from basil Ocimum different cultivars

BackgroundThe plants belonging to the Ocimum genus of the Lamiaceae family are considered to be a rich source of essential oils which have expressed biological activity and use in different area of human activity. There is a great variety of chemotypes within the same basil species. Essential oils from three different cultivars of basil, O. basilicum var. purpureum, O. basilicum var. thyrsiflora, and O. citriodorum Vis. were the subjects of our investigations.MethodsThe oils were obtained by steam distillation in a Clevenger-type apparatus. The gas chromatography mass selective analysis was used to determine their chemical composition. The antioxidant activities of these essential oils were measured using 1,1-diphenyl-2-picrylhydrazyl assays; the tyrosinase inhibition abilities of the given group of oils were also assessed spectophotometrically, and the antimicrobial activity of the essential oils was determined by the agar diffusion method, minimal inhibitory concentrations were expressed.ResultsAccording to the results, the qualitative and quantitative composition of essential oils was quite different: O. basilicum var. purpureum essential oil contained 57.3% methyl-chavicol (estragol); O. basilicum var. thyrsiflora oil had 68.0% linalool. The main constituents of O. citriodorum oil were nerol (23.0%) and citral (20.7%). The highest antioxidant activity was demonstrated by O. basilicum var. thyrsiflora essential oil. This oil has also exhibited the highest tyrosinase inhibition level, whereas the oil from O. citriodorum cultivar demonstrated the highest antimicrobial activity.ConclusionsThe results obtained indicate that these essential oils have antioxidant, antibacterial and antifungal activity and can be used as natural antioxidant and antimicrobial agents in medicine, food industry and cosmetics.

Responses of basil cultivars to irrigation water salinity

ABSTRACT The objective of this work was to verify the response of basil cultivars to the salinity of irrigation water during the period from January 15 to March 20, 2013, in a greenhouse, at the Federal Rural University of the Semi-Arid, Mossoró, RN, Brazil. The experimental design was completely randomized, with treatments arranged in 2 x 4 factorial scheme, constituted of two cultivars of basil (‘Verde’ and ‘Roxo’) and four levels of irrigation water salinity (0.5; 2.0; 3.5 and 5.0 dS m-1), with four replicates. The plants were collected at 65 days after transplanting and the following variables were evaluated: stem diameter; plant height; number of stems and leaves; leaf area; dry matter of leaves, stems, roots, and total dry matter. The increase in salinity was detrimental to all variables evaluated in both cultivars, but the cultivar ‘Roxo’ proved to be more tolerant than the cultivar ‘Verde’. Both cultivars are tolerant to irrigation water salinity of up to 1.5 dS m-1.

Antioxidant and antimicrobial properties of traditional green and purple “Napoletano” basil cultivars (Ocimum basilicum L.) from Campania region (Italy)

The present study is the first effort to a comprehensive evaluation of the antioxidant and antimicrobial activities of ‘Napoletano’ green and purple basil (Ocimum basilicum L.) varieties. The results obtained revealed that the basil sample extracts were characterised by a generally higher polyphenolic concentration than those reported elsewhere for other more conventional and geographically different basil varieties. Napoletano purple basil revealed higher radical-scavenging and ferric-reducing capacities than the green one probably due to its relevant anthocyanin content. As regards the antimicrobial properties, both basil varieties exhibited activity against a broad spectrum of food-borne and human pathogenic micro-organisms, revealing not only a moderate to high natural preserving capacity, but also potentially beneficial influence on human health. Results indicated Napoletano green and purple basils as a good source of antioxidants of potential nutraceutical interest.

Growth, yield, plant quality and nutrition of basil (Ocimum basilicum L.) under soilless agricultural systems

Traditional agricultural systems are challenged by globally declining resources resulting from climate change and growing population. Alternative agricultural practices such as aquaponics (includes crop plant and aquatic species) and hydroponics (includes crop plant only) have the potential to generate high yield per unit area using limited land, water, and no soil. A soilless agricultural study was conducted at the Georgia Southern University, Statesboro, GA, USA from August to November, 2015. The growth, yield, quality, and nutrition of basil (Ocimum basilicum L.) cultivar Aroma 2, were compared between aquaponic and hydroponic systems using crayfish (Procambarus spp.) as the aquatic species. Non-circulating floating raft systems were designed using 95L polyethylene tanks. Equal amounts of start-up fertilizer dose were applied to both systems. The objective was to understand how the additional nutritional dynamics associated with crayfish influence the basil crop. Both fresh and dry basil plant weights were collected after harvest, followed by leaf nutrient analysis. Leaf chlorophyll content, water pH, nitrogen and temperature were measured periodically. Aquaponic basil (AqB) showed 14%, 56%, and 65% more height, fresh weight, and dry weight, respectively, compared to hydroponic basil (HyB). It is logical to assume that crayfish waste (excreta and unconsumed feed) has supplied the additional nutrients to AqB, resulting in greater growth and yield. The chlorophyll content (plant quality) or leaf nutrients, however, did not differ between AqB and HyB. Further research is needed to investigate aquaponic crayfish yield, overall nutritional dynamics, cost-benefit ratio, and other plant characteristics under soilless systems.

Morphological Characteristics and Susceptibility of Basil Species and Cultivars to Peronospora belbahrii

Sweet basil (Ocimum basilicum) is the most economically important culinary herb in the United States. In 2007, a new disease, basil downy mildew (BDM), caused by the oomycete pathogen Peronospora belbahrii, was introduced into the United States and has since caused significant losses in commercial basil production. Although no commercial sweet basils available are resistant to P. belbahrii, other species of Ocimum have exhibited potential tolerance, resistance, or both. The objectives of this work were to determine if leaf morphological characteristics including stomata density and leaf curvature correlated with infection of plants by P. belbahrii, and thus could be used as selected characters in plant breeding. In 2011, 20 Ocimum cultivars including sweet (O. basilicum), cinnamon (O. basilicum), clove (O. basilicum), citrus (Ocimum ×africanum syn. Ocimum citriodorum), spice (Ocimum americanum syn. Ocimum canum), and holy basils (Ocimum tenuiflorum syn. Ocimum sanctum) were evaluated for susceptibility to downy mildew. Sweet basils were determined to be the most susceptible; cinnamon, clove, and Thai types were moderately susceptible; and citrus, spice, and holy types were least susceptible to downy mildew. Using those same 20 Ocimum species and cultivars, stomata length and density and leaf curvature were measured and correlated with downy mildew incidence and severity. In general, basil species with higher stomatal densities had higher downy mildew incidence and severity. High stomatal densities were mainly found in the sweet, cinnamon, and clove basils. Citrus and spice species with longer stomatal lengths generally exhibited lower downy mildew incidence. Holy basil, the least susceptible of all Ocimum sp. to P. belbahrii evaluated in this study, had the greatest stomatal density and shortest stomatal length. Some sweet basil cultivars with the highest downy mildew incidence also had the greatest downward leaf curvature, whereas other sweet basil cultivars with moderate downy mildew incidence had leaves that were nearly flat or curved upward. Holy, citrus, and spice basils with low downy mildew incidence had leaves that were nearly flat or curved upward. This study suggests that leaf curvature and stomatal density and length affect downy mildew development and sporulation. Considerations of these leaf morphological characteristics may be useful phenotypic traits in breeding for downy mildew resistance in Ocimum.