Scientia Agropecuaria

Effect of the conditioning and ultrasound-microwave sequential technique on the yield, chemical and functional properties of the essential oils and hydrolats extracted from the leaves of Tagetes elliptica Smith

Resumen La regulación térmica y el ultrasonido afectan las propiedades físicas, químicas y antioxidantes de los aceites esenciales e hidrosoles obtenidos por extracción con microondas de las hojas de Tagetes elliptica S. (chincho). Para ello, las hojas fueron acondicionadas por deshidratación o congelación, luego pretratadas con ultrasonido por 15 o 30 minutos a 40Hz, para finalmente obtener el aceite esencial (AECH) e hidrolato (HCH) mediante una extracción por microondas (500W y 30 minutos). Se evaluó los rendimientos, contenido fenólico, capacidad antioxidante, estructura de las hojas mediante microscopía óptica y composición química por cromatografía de gases y espectrometría de masas (CG-MS). Un acondicionamiento de las hojas por congelación y una sonicación por 30 minutos, obtuvo el mejor rendimiento, 8,86±0,1% y 67,40±4,8%, contenido fenólico de 39,4±0,1 mg EAG/mL y 346,2 ± 13,6 mg EAG/mL, y capacidad antioxidante de 35,7 μmol EqT/mg y 0,25 μmol EqT/mg equivalente, para AECH e HCH; respectivamente en cada caso. El daño estructural de las hojas fue observado por efecto de los tratamientos recibidos acondicionamiento-ultrasonido-microondas, logrando una mayor liberación de compuestos bioactivos. Los compuestos mayoritarios del aceite esencial fueron las tagetenonas (49,2%), seguido por cis-miróxido (14,5%), dihidrotagetona (13,9%), tagetona (9,8 %) y ocimeno (2,4%); los compuestos mayoritarios en el hidrolato fueron el cis-miróxido (44,66%), seguido por cis-tagetona (23,84%), trans-tagetona (12,24%), óxido de linanool (5,48%) y dihidrotagetona (4,04%). El aporte significativo del presente estudio son las técnicas de extracción y el perfil químico de los extractos de Tagetes elliptica.

Abstract Thermal regulation and ultrasound affect the physical, chemical, and antioxidant properties of essential oils and hydrosols extracted by microwaves from the leaves of Tagetes elliptica S. (chincho). The leaves were conditioned by dehydration or freezing, then pre-treated with ultrasound for 15 or 30 minutes at 40 Hz to finally obtain the essential oil (AECH) and hydrolat (HCH) through microwave extraction (500 W and 30 minutes). Yields, phenolic content, antioxidant capacity, leaf structure by optical microscopy, and chemical composition by gas chromatography and mass spectrometry (GC-MS) were evaluated. The conditioning of the leaves by freezing and sonication for 30 minutes obtained the best performance, 8.86±0.1% and 67.40 ± 4.8%, phenolic content of 39.4±0.1 mg EAG/mL and 346.2 ± 13.6 mg EAG/mL, and antioxidant capacity of 35.7 μmol EqT/mg and 0.25 μmol EqT/mg equivalent, for AECH and HCH, respectively in every case. Structural damage of the leaves was observed due to the effect of the conditioning-ultrasound-microwave treatments, achieving a more significant release of bioactive compounds. The main compounds of the essential oil were tagetenones (49.2%), followed by cis-miroxide (14.5%), dihydrotagetone (13.9%), tagetone (9.8%) and ocimene (2.4%); the main compounds in the hydrolate were cis-myroxide (44.66%), followed by cis- tagetone (23.84%), trans-tagetone (12.24%), linalool oxide (5.48%) and dihydrotagetone (4.04%). The significant contribution of the present study is the extraction techniques and chemical profile of tagetes elliptica extracts.

Trophic networks associated with the corn leaf aphid, Rhopalosiphum maidis (Fitch, 1856) (Hemiptera: Aphididae) in a cornfield, Manabí, Ecuador

Abstract The corn leaf aphid is considered an important pest associated with maize. This study aimed to discover the trophic associations around Rhopalosiphum maidis in Manabí, Ecuador. Maize leaves were sampled to determine the numbers of parasitized aphids, and the identities of predators and parasitoids. Nine taxa of natural enemies were detected: the primary parasitoid was Lysiphlebus testaceipes Cresson, 1880 (Hymenoptera: Braconidae); the hyperparasitoid Syrphophagus aphidivorus (Mayr, 1876) (Hymenoptera: Encyrtidae); the predatory hoverfly Ocyptamus dimidiatus (Fabricius, 1781) (Diptera: Syrphidae), four species of coccinellids, Cheilomenes sexmaculata (Fabricius, 1781), Cycloneda sanguinea (Linnaeus, 1763), Hippodamia convergens Guerin-Meneville, 1842 and Paraneda pallidula guticollis (Coleoptera: Coccinellidae) and an assassin bug, Zelus sp. (Hemiptera: Reduviidae). A parasitoid, Pachyneuron formosum Walker, 1833 (Hymenoptera: Pteromalidae) emerged from hoverfly pupae. This study reports the presence of the parasitoids S. aphidivorus and P. formosum in Ecuador for the first time. These results increase the knowledge of a four-trophic level relationship (host plant - pest - parasitoids, predators - hyperparasitoids) in a maize agroecosystem as a fundamental basis for biological control programs.

An organic management alternative that improves soil quality in cocoa plantations under agroforestry systems

Abstract The organic management of Theobroma cacao in agroforestry systems is a viable alternative, which is being applied in the Alborada Estate under the name of Mendis Organic Management (MOM) in honor of the researcher and owner of the experimental area. The MOM technology integrates a set of techniques according to the physiological cycle of the plant such as drastic annual pruning, application of compost, foliar biofertilizer, and the use of a variety of cocoa with high planting density. Therefore, the research evaluated the effect of MOM management on soil quality with cocoa plantations (varieties CCN-51 and CMP-15), under agroforestry system developed in the Alborada farm, Leoncio Prado province, Huanuco, Peru. A completely randomized design (CRD) was carried out, the treatments were cocoa areas: CCN-51 of 2x2 m and 10 years of installation (MOM1), CMP-15 of 2x2 m and 4 years (MOM2), CMP-15 of 2x1 m and 5 years (MOM3), CMP-15 of 3x2 m and 13 years (MOM4). Soil physical and chemical indicators were evaluated. All indicators showed significant differences between treatments, the principal component analysis (PCA) considered relevant the sand fraction, clay, OM, N, Ca2+, Mg2+, K+ and CEC, the modeling shows a negative impact in MOM2 and significantly positive in MOM4, regardless of the variety and planting density, observing significant increases for pH, OM, N, P, Ca2+, Ma2+ and CEC. The work shows the great potential of MOM management as a technological alternative to improve soil quality in cocoa plantations under agroforestry systems.

Characterization of Fusarium species that affect the asparagus crops cultivation in Veracruz, Mexico

Resumen El cultivo de espárragos es altamente rentable, y es apreciado en la gastronomía gourmet internacional. En México la producción de este vegetal es principalmente de exportación, en el estado de Veracruz es de reciente introducción. El objetivo de la investigación fue caracterizar por morfología, técnicas moleculares y pruebas de patogenicidad las especies de Fusarium aislados de tejidos sintomáticos de turiones de espárrago. Se realizó un muestreo dirigido en plantas que presentaban pudrición, marchitez y manchas de color marrón obscuro. Los aislamientos fúngicos se obtuvieron a partir de turiones enfermos, que fueron desinfectados y sembrados en papa dextrosa agar. Los aislamientos se purificaron en cultivos monospóricos por punta de hifa. Se identificaron cuatro especies de Fusarium por morfología taxonómica, en medio selectivo agar hoja de clavel, luego se realizaron pruebas de patogenicidad cumpliendo con los postulados de Koch. En seguida se caracterizaron por técnicas moleculares a las cepas que resultaron patógenas, y se corroboró su identidad como Fusarium oxysporum y Fusarium proliferatum. Lo información obtenida permite implementar estrategias de manejo apropiadas para las especies patógenas, y con ello evitar pérdidas económicas a corto, mediano y largo plazo en el cultivo de espárrago.

Abstract Asparagus cultivation is highly profitable and is appreciated in international gourmet cuisine. In Mexico, the production of this vegetable is mainly for export, in the state of Veracruz it has been recently introduced. The objective of the research was to characterize by morphology, molecular techniques and pathogenicity test the Fusarium species isolated from symptomatic tissues of asparagus shoot. A directed sampling was carried out on plants that showed rot, wilting and dark brown spots. Fungal isolates were obtained from diseased shoots, which were disinfected and seeded on potato dextrose agar. Isolates were purified in monosporic cultures by hyphal tip. Four species of Fusarium were identified by taxonomic morphology, in a selective carnation leaf agar medium, then pathogenicity tests were carried out, complying with Koch's postulates. Next, the strains that were pathogenic were characterized by molecular techniques, and their identity as Fusarium oxysporum and Fusarium proliferatum was confirmed. The information obtained allows the implementation of appropriate management strategies for pathogenic species and thereby avoids economic losses in the short, medium, and long term in the asparagus crop.

Natural and commercial antimicrobial agents that inhibit the growth of Listeria monocytogenes strains

Abstract Vinegar products have gained popularity as an all-natural antimicrobial agent in recent years. In the present study, the antimicrobial susceptibility of 29 Listeria monocytogenes strains isolated from ready-to-eat foods was detected against natural and commercial antimicrobial agents, vinegar produced from different raw materials, lemon juice, sodium bicarbonate, and hydrogen peroxide, by using the disc diffusion method. Different concentrations of antimicrobial agents were tested against varying cell densities of the L. monocytogenes strain (105, 106, and 107 CFU/mL). The inhibition zone diameter was measured to evaluate the antimicrobial effects of antimicrobial agents on L. monocytogenes strains. The inhibition zone diameters of L. monocytogenes strains were 6.0-8.8 mm and 6.0-11.3 mm against traditional and commercial vinegar types, respectively. The commercial vinegar types showed higher antimicrobial efficacy than the conventional ones. The inhibition zone diameters of L. monocytogenes strains against carbonate, lemon juice, and hydrogen peroxide were 6.0, 6.0-9.0, and 33.9-51.9 mm, respectively. The antimicrobial efficacy of hydrogen peroxide was the highest among the tested antimicrobial agents. This study showed that vinegar products have potential to be utilized as natural antimicrobials on food-borne pathogens like L. monocytogenes.

Incorporation of nisin and oregano essential oil in cow’s milk to improve the quality of fresh cheese

Abstract Firstly, this study aimed to determine the effect of adding nisin (0, 250 and 500 IU mL-1) and oregano essential oil (OEO) (0, 0.025% and 0.05%), alone or in combination, on Staphylococcus aureus load in cow’s milk. Next, it was evaluated the sensory, physicochemical and microbiological quality of fresh cheese (FC) manufactured with milk added of nisin + OEO (C1) or nisin alone (C2) compared to a control cheese (C0, milk without the addition of nisin or OEO). Results showed that adding nisin effectively reduced the S. aureus count in milk in a similar manner to adding way the combination of nisin + OEO compared to the control. FC quality evaluation results revealed that C1 and C2 did not alter the physicochemical quality of FC (pH, fat and total solids content) during storage (0-8 days) compared to the control. Furthermore, C1 and C2 reduced in a similar manner aerobic mesophilic bacteria and Enterobacteriaceae count in FC compared to the control during storage. Sensory evaluation showed that consumers did not value FC added of nisin + OEO (C1) due to its intense aroma of oregano, rating it with the lowest global quality.

A citrus essential oil causes higher disturbance on the growth kinetics of Enterococcus faecalis than Lactobacillus rhamnosus

Abstract Essential oils (EOs) have turned a promising alternative to using antibiotics in poultry production due to their antimicrobial properties. EOs could effectively combat pathogenic bacteria affecting poultry. Particularly, Citrus EOs, a by-product of citrus processing industries, could be a feasible alternative to this end due to their vast availability in the global market. Enterococci are associated with intestinal and extra-intestinal infections in poultry, which can increase poultry mortality. On the other hand, Lactobacilli are beneficial bacteria inhabiting the poultry gut and have health-promoting effects. The aim of this study was to evaluate the antibacterial activity of a commercial citrus EO, Orange oil phase essence (OOPE), on Enterococcus faecalis and Lactobacillus rhamnosus as well as to determine OOPE chemical composition. Results showed that OOPE inhibited E. faecalis and L. rhamnosus at 14.8 mg/mL. However, the evaluation of OOPE effects on the growth kinetics parameters of both bacteria reveled that OOPE caused higher disturbances on the growth kinetics of E. faecalis than L. rhamnosus. OOPE significantly reduced the maximal culture density (A) and growth rate (µmax) and extended the lag phase duration (λ) of E. faecalis in a dose-dependent manner, while OOPE slightly extended λ and affected µmax of L. rhamnosus. OOPE at 3.70 mg/mL reduced A and µmax in ~87.34 and 90.2%, respectively, while increased λ 3.8 times of E. faecalis. OOPE at this concentration reduced µmax in 11.8% and extended λ 1.38 times of L. rhamnosus. Therefore, OOPE had a selective antibacterial activity, presenting higher activity on E. faecalis. Despite, limonene was identified as the major compound (87.22%) of OOPE, minor compounds such as trans-carveol could be involved in conferring the selective antibacterial activity of OOPE.

Phenotypic diversity of Amaranthus quitensis Kunth landraces: A millenary crop of Ecuadorian Andean region

Abstract The black amaranth (Amaranthus quitensis Kunth) is traditionally cultivated in the Ecuadorian highlands, where it has great social, cultural and food importance for the native population, and locally it is called ataco or sangorache. Currently, there are no data on the diversity and conservation status in which the ataco landraces are found. We have evaluated the phenotypic diversity of black amaranth landraces collected at two different times (1981-1986 and 2014-2015) in three representative Andean provinces for this crop (Imbabura, Tungurahua and Cañar). Thirty agro-morphological descriptors were used, 11 quantitative and 19 qualitative. Most of the quantitative traits showed high levels of variation, especially grain yield per plant. The qualitative traits showed less diversity, although the characters related to the plant pigmentation and the shape and attitude of the inflorescence were significantly discriminating between accessions from different provinces. Few significant differences were detected between both collects, so the farmers seem to be carrying out adequate on-farm conservation of the ataco germplasm. The agro-morphological information obtained in this study may be useful for enhancing the use of this plant genetic resource in future amaranth breeding programs, as well as for effectively managing the black amaranth collection from Germplasm Bank of the Ecuadorian National Institute for Agricultural Research (INIAP).

Use of Andean pseudocereals in beer production

Abstract Beer is one of the most consumed alcoholic beverages worldwide; however, with consumers more aware of food's environmental and nutritional benefits, there is a demand for more sustainable and value-added products. Andean pseudocereals (APS) are becoming a trend as gluten-free grains with excellent nutritional and nutraceutical value. Cultivated under the extreme climate conditions of the Peruvian Andes, APS seeds are an excellent source of starch, fiber, proteins, minerals, vitamins, and bioactive compounds such as phenolic acids and flavonoids with antioxidant capacity that provide potential health benefits. This review is a compilation of the information and studies on the general characteristics and potential of the main APS as quinoa, amaranth, and cañihua for beer production. In addition, current evidence of the malting process in APS and its effects on beer's nutritional, functional, and sensory properties are also provided. Based on the research supporting the pseudocereals inclusion for the formulation of foods for celiac people, this review also looks at recent advances in applying APS to develop traditional and gluten-free (GF) beers. Finally, APS's economic, cultural, and social importance in the brewing industry is highlighted to promote the creation and innovation of fermentative products based on their bioactive compounds, thus achieving better commercial exploration of these ancestral grains.

Emergence, growth and plant quality of two papaya (Carica papaya L.) genotypes inoculated with entomopathogenic fungi

Resumen La papaya (Carica papaya L.) es un cultivo de importancia económica en México y América Latina. La fase de vivero juega un papel primordial en el proceso de producción, en esta etapa es susceptible a plagas y enfermedades. El uso de biofertilizantes a base de hongos entomopatógenos (HE) es una alternativa para producir plántulas sanas y de calidad, a través de la agricultura biológica. El objetivo fue evaluar la habilidad de Beauveria brongniartii y Purpureocilium lilacinum para colonizar tejidos, promover la emergencia y mejorar la calidad de planta de dos genotipos de papaya en vivero. Se estableció un experimento con diseño factorial A×B [A = genotipo: híbrido “Intenzza” y var. “Maradol”) y B = inoculación de B. brongniartii (Bb), P. lilacinum (Pl) y sin inoculación]. Se cuantificó, el porcentaje de emergencia (PE), Altura de Planta (AP), Diámetro de Tallo (DT), Biomasa Fresca (BF) y Seca (BS), endofitismo, Índice de Lignificación (ILIG) y Calidad de Dickson (ICD). El PE incrementó (6%, P = 0,0043) con la inoculación de Bb. Ambos HE incrementaron la AP (P = 0,00001) en 0,38 (Bb) y 0,37 cm (Pl), y el DT (P = 0,00001) en 0,24 (Bb) y 0,23 mm (Pl), respectivamente. La BF aérea y radicular (P = 0,0003) incrementó con Bb y Pl en 0,16 y 0,1 g y 0,17 y 0,1 g, respectivamente. El ILIG (P = 0,0128) e ICD (P = 0,0433) fueron superiores con Bb. Tanto Bb y Pl colonizaron diferentes tejidos de la planta. La inoculación de Bb promovió la emergencia de semillas. Ambos HE lograron colonizar endofíticamente diferentes órganos de la planta y favorecieron su calidad.

Abstract The papaya (Carica papaya L.) is an economically important crop in Mexico and Latin America. The nursery phase plays a primary role in the production process, at this stage, it is susceptible to pests and diseases. The use of biofertilizers based on entomopathogenic fungi (EF) is an alternative to produce healthy and quality seedlings, through biological agriculture. The objective was to evaluate the ability of Beauveria brongniartii and Purpureocilium lilacinum to colonize tissues, promote emergence and improve the plant quality of two papaya genotypes in nursery. An experiment with factorial design A×B was established [A = papaya genotype (hybrid '“Intenzza” and var. “Maradol”) and B = inoculation of B. brongniartii (Bb), P. lilacinum (Pl) and without microorganism]. Emergence percentage (EP), Plant Height (PH), Stem Diameter (SD), Fresh Biomass (FB) and Dry Biomass (DB), endophytism, Lignification Index (LIGI) and Dickson Quality (DQI) were quantified. EP increased (6%, P = 0.0043) with Bb inoculation. Both EF increased the PH (P = 0.00001) by 0.38 (Bb) and 0.37 cm (Pl), and the ST (P = 0.00001) by 0.24 (Bb) and 0.23 mm (Pl), respectively. Aerial and root FB (P = 0.0003) increased with Bb and Pl by 0.16 and 0.1 g, and 0.17 and 0.1 g, respectively. LIGI (P = 0.0128) and QDI (P = 0.0433) were higher with Bb. Both EF colonized different plant tissues. Bb inoculation promoted seed emergence, both EF were able to colonize endophytically different organs of the plant and favored its quality.

Candidate rhizobacteria as plant growth-promoters and root-knot nematode controllers in tomato plants

Abstract Meloidogyne incognita root-knot nematode is one of the main causes of tomato root damage and consequently crop production losses. Thus, in in vitro conditions, the number of nematodes hatched eggs (%) at 4 and 6 days and nematode mortality (J2 stage) at 8, 18, and 24 h, were evaluated in Petri dishes containing the candidate rhizobacteria Enterobacter asburiae (BA4-19 and PM3-14), Acinetobacter calcoaceticus (BM2-12), Klebsiella variicola (BO3-4) and Serratia marcescens (PM3-8). The well-known Pseudomonas protegens (CHA0) and P. veronii (R4) were used as controls. In greenhouse conditions, plant height, root weight, and symptoms, as well as gall and nematode numbers, were determined in tomato plants infected by M. incognita and treated with the seven rhizobacteria. In addition, all variables were correlated using Pearson's analysis. In general, a significant correlation was observed among the variables of both experiments, showing the antagonistic capacity of the strains against nematode. It seems, that PM3-8 and PM3-14 strains reduce hatching, and cause mortality of nematodes J2 if compared with CHA0 and R4 strains. Likewise, tomato treated with BM2-12 strain shows a higher height and root weight, as well as a smaller number of galls and nematodes in their roots. This study provides evidence that PM3-8 and PM3-14 strains reduce the M. incognita egg hatching, and that the BM2-12 strain can be a plant growth-promoter potential of tomato plants.