Organic mango production in Mexico: Status of orchard management

Eight percent of total planted area in Mexico is in the process to change from conventional to organic system mainly in the Pacific Coast under tropical dry and wet conditions. Mango cultivars in organic systems are 'Tommy Atkins', 'Kent', 'Ataulfo' which are demanded by market and early or late season of harvest. Cultivars are grafted on local polyembrionic rootstock well adapted to different soil types, they remain vigorous but tolerance to soil diseases has not been proved yet. Information of better combinations of rootstocks and cultivars appropriated for organic production and adapted to variable soil conditions, is needed. Plant densities range 100 to 200 trees ha -1, but are rapidly changing to higher tree densities. Either, tillage practices or cover crops are used to avoid herbicides to control weeds in between tree rows. Pruning of trees is a very important activity applied by growers to control tree size, avoid pest and diseases and promote better light conditions in internal canopy to improve fruit color. Many diseases affect tree foliage, flowering and fruits and are properly controlled using permitted products listed by IFOAM. However organic and more efficient alternatives are needed in order to control the wide diversity of diseases in the field. In addition to field applications, anthracnose damage on fruits is controlled by means of postharvest hot water treatments. Fruit flies are important pests, but they are kept under control with integrated management program applied to different regions according to population levels. Several organic products are used to fertilize orchards, but beneficial impact on fruit production and quality remain to be thoroughly clarified

Organic mango production in Mexico: Status of orchard management

Eight percent of total planted area in Mexico is in the process to change from conventional to organic system mainly in the Pacific Coast under tropical dry and wet conditions. Mango cultivars in organic systems are 'Tommy Atkins', 'Kent', 'Ataulfo' which are demanded by market and early or late season of harvest. Cultivars are grafted on local polyembrionic rootstock well adapted to different soil types, they remain vigorous but tolerance to soil diseases has not been proved yet. Information of better combinations of rootstocks and cultivars appropriated for organic production and adapted to variable soil conditions, is needed. Plant densities range 100 to 200 trees ha -1, but are rapidly changing to higher tree densities. Either, tillage practices or cover crops are used to avoid herbicides to control weeds in between tree rows. Pruning of trees is a very important activity applied by growers to control tree size, avoid pest and diseases and promote better light conditions in internal canopy to improve fruit color. Many diseases affect tree foliage, flowering and fruits and are properly controlled using permitted products listed by IFOAM. However organic and more efficient alternatives are needed in order to control the wide diversity of diseases in the field. In addition to field applications, anthracnose damage on fruits is controlled by means of postharvest hot water treatments. Fruit flies are important pests, but they are kept under control with integrated management program applied to different regions according to population levels. Several organic products are used to fertilize orchards, but beneficial impact on fruit production and quality remain to be thoroughly clarified

Vegetative and reproductive relationships in Mexican lime trees under tropical conditions

This work was carried out to determine the influence of seasons of vegetative shoots on the time of flowering and to known the intervals from flowering to fruit harvest of Mexican lime trees. Two experiments on a seven years old Mexican lime trees budded on Sour Orange rootstock were established. In experiment 1, the number of vegetative (VS) and reproductive shoots (RS) on each one of 10 trees were registered weekly during one year, using a metallic ring of one square meter area placed on the tree 1.75 m from the ground. Minimum temperature and rainfall data were also recorded every week. In experiment 2, monthly, ten new vegetative shoots on each one of ten trees were tagged. These shoots were observed every week until they bloom. During the most important periods of blooming, five flowering shoots per tree were chosen to determine interval to harvest. In experiment 1, four VS and two RS flushes were observed. The first period of VS and RS started in autumn and was associated to the initiation of irrigation. The second and more important was registered in January when temperatures were the lowest of the year. Half RS and half VS were recorded during this period. The third and four flushes were mainly VS and occurred during summer months with highest temperatures and the rainy season. In experiment 2, from the vegetative shoots emerging in January, 52% formed reproductive shoots 60-85 days later and 25% also flowered sparsely four to six months later. The remaining shoots (23%) repeated their vegetative activity during June and July. Most of the vegetative shoots initiated in February showed again a vegetative activity during May to July, and only 20% of them changed to reproductive. New vegetative shoots appeared from March to July showed a vegetative activity during the next two to six months. From the vegetative shoots emerged from July to September very few (15%) transformed to reproductive during November-December and the majority became vegetative again, however, most of them changed to reproductive from January to April. Fruits initiating during the winter time lasted 130 to 145 days until harvest. But those fruits emerged during the late spring and summer months reached complete development 90 to 120 days later. These combined phenological characteristics explain the long period of harvest showed by the MLT under tropical semiarid conditions

Identification and characterisation of bacteria causing soft-rot in Agave tequilana

Agave tequilana is the raw material for the production of the alcoholic beverage tequila. A bacterial disease has affected the A. tequilana crop in recent years. Previous reports based on colony and cell morphology, Gram stain and potato rot indicated that Erwinia sp. is the main pathogen. We isolated a several bacterial isolates capable of producing soft-rot symptoms in greenhouse pathogenicity assays. An extensive characterisation involving pathogenicity tests, fatty acid profile, metabolic and physiological properties, ribosomal DNA sequence and intergenic transcribed spacer amplification (ITS-PCR) and restriction banding pattern (ITS-RFLP) was made of each isolate. Three different species: Erwinia cacticida, Pantoea agglomerans and Pseudomonas sp. were identified. Fatty acid and metabolic profiles gave low similarity values of identification but 16S rDNA sequence, ITS-PCR and ITS-RFLP confirmed the identification of E. cacticida. In the phylogenetic tree, E. cacticida from blue agave was grouped neither with E. cacticida type strains nor with Erwinia carotovora. This is the first report that associates E. cacticida with A. tequilana soft-rot symptoms

Anti-inflammatory effect of microbial consortia during the utilization of dietary polysaccharides

© 2018 Elsevier Ltd The gut microbiome has a significant impact on host health, especially at the metabolic level. Dietary compounds arriving at the colon have a large influence on the composition of the gut microbiome. High fiber diets have been associated to health benefits that are mediated in great part by short chain fatty acids (SCFA). Gut microbial interactions are relevant for the utilization of complex carbohydrates in the gut microbiome. In this work we characterized the utilization of two dietary polysaccharides by combinations of representative adult gut microbes, and the impact of their activities on a cellular inflammation model. Paired combinations of Bifidobacterium adolescentis, Bacteroides dorei, Lactobacillus plantarum, Escherichia coli and Clostridium symbiosum were grown in inulin or xylan as carbon source. Their relative abundance, substrate consumption and major SCFAs produced were determined. Higher cell growth was observed during inulin consumption, and B. ado

Feedback-related negativity is enhanced in adolescence during a gambling task with and without probabilistic reinforcement learning

Several reports have shown that crude or purified extracts of green, brown, and red seaweeds induce protection against fungal, bacterial, and viral pathogens in plants. In this work, we report that polysaccharide-enriched seaweed extracts obtained from green, Ulva lactuca and Caulerpa sertularioides, and brown algae, Padina gymnospora and Sargassum liebmannii, induced protection against the necrotrophic fungus Alternaria solani in tomato plants (Solanum lycopersicum). Protein activity of defense-related proteins polyphenol oxidase, guaiacol peroxidase and proteinase inhibitors together with expression levels of systemic wound response (SWRP) genes were also measured in leaf samples after algal extract treatment. All extracts were shown to reduce necrotic lesions induced by A. solani, particularly those obtained from U. lactuca and P. gymnospora. U. lactuca extracts induced the expression of SWRP genes, including defense, signal pathway, and protease genes, whereas those obtained from C. sertularioides, P. gymnospora and S. liebmannii showed almost no induction of SWRP genes, suggesting that extracts from the latter, whose carbohydrate composition varied from that of U. lactuca, may act through mechanisms other than the jasmonic acid/systemin wound-response pathway. " 2013 Springer Science+Business Media Dordrecht.",,,,,,"10.1007/s10811-013-0193-2",,,"http://hdl.handle.net/20.500.12104/41423","http://www.scopus.com/inward/record.url?eid=2-s2.0-84900847798&partnerID=40&md5=b9417f40c3ef95ee816be5444280268a",,,,,,"3",,"Journal of Applied Phycology",,"160

Lethal dosis (LD50) determination using Co60 on agave tequilana var. Azul vitroplantlets [Determinación de la dosis letal (DL50) con Co60 en vitroplántulas DE Agave tequilana var. Azul]

The agave crop (Agave tequilana Weber var. 'Azul') is the source for tequila. It has important social, cultural and economic impacts, particularly on employment needed to fulfill the activities around the crop and industry. Low genetic diversity is present in the cultivar; thus, induction of genetic variability via mutagenesis can be an option. In this research the mean lethal dose (LD50) of Co60 gamma rays for inducing genetic variability on agave in vitro callus and plantlets was quantified. Plantlets were obtained by incubating agave explants on a Murashige and Skoog (MS) medium containing growth regulators which promoted growth of axillary buds. Calli were irradiated six weeks after induction and plantlets at 12 weeks of development. In both cases, doses applied were: 0 (control), 10, 20, 30, 40 and 50 Gy. Statistically differences were obtained for plantlets and calli growth; significant effects appeared at radiation level above 20 Gy for calli and 30 Gy for plantlets. Linear and quadratic regression models between doses and variables were appropriate; R2 for the linear model was 0.62, while the quadratic model had R2 = 0.74. LD50 was fixed between 20 and 25 Gy for plantlets and 16 Gy for callus, based on the quadratic model

Lethal dosis (LD50) determination using Co60 on agave tequilana var. Azul vitroplantlets [Determinación de la dosis letal (DL50) con Co60 en vitroplántulas DE Agave tequilana var. Azul]

The agave crop (Agave tequilana Weber var. 'Azul') is the source for tequila. It has important social, cultural and economic impacts, particularly on employment needed to fulfill the activities around the crop and industry. Low genetic diversity is present in the cultivar; thus, induction of genetic variability via mutagenesis can be an option. In this research the mean lethal dose (LD50) of Co60 gamma rays for inducing genetic variability on agave in vitro callus and plantlets was quantified. Plantlets were obtained by incubating agave explants on a Murashige and Skoog (MS) medium containing growth regulators which promoted growth of axillary buds. Calli were irradiated six weeks after induction and plantlets at 12 weeks of development. In both cases, doses applied were: 0 (control), 10, 20, 30, 40 and 50 Gy. Statistically differences were obtained for plantlets and calli growth; significant effects appeared at radiation level above 20 Gy for calli and 30 Gy for plantlets. Linear and quadratic regression models between doses and variables were appropriate; R2 for the linear model was 0.62, while the quadratic model had R2 = 0.74. LD50 was fixed between 20 and 25 Gy for plantlets and 16 Gy for callus, based on the quadratic model

Micropropagation of agave (Agave tequilana Weber. var. Azul) through axillary buds [Microprogapación de agave (Agave tequilana Weber. Var. Azul) a través de yemas axilares]

Agave (Agave tequilana Weber var. azul), is commonly called, "Blue Agave or Agave Tequilero". The agave plant is an important economic product of Mexico due to its base ingredient is Tequila, which is a popular distilled spirit. Agave in vitro propagation is a new technique to obtain rapid multiplication in a short time. The plant response to hormones must be evaluated for each species of Agave. The objective for this research was to generate agave plantlets from axillary buds by in vitro culture. Six month aged plants were brought from the production field. Buds were disinfected with 70% alcohol and 3% sodium hypochlorite for 15 minutes and triple rinsed under aseptic conditions. Explants were cultured in Murashige & Skoog (MS) medium, supplemented with 24.6 μM of AIB and 46.46 μM of Kinetin, sucrose 30 g L-1 and agar 8 g L-1. Medium was added at 25 mL per flask and sterilized at 121°C for 15 minutes. One explant per flask was cultured and incubated at 27°C and 16 hours light. The bud induction appears in four weeks after it was cultured and then they were subcultured in MS supplemented with 0.5 μM of AIB and 46.46 μM of Kinetin. The plantlets development was reached at four weeks after the buds induction. Agave micropropagation from auxiliary buds was completed within 10 weeks. The time required to get in vitro-plants were demonstrated using the in vitro technique propagation. It is an efficient process of mass multiplication to obtain healthy, pathogen free and vigorous plants

Insecticide resistance in adult diaphorina citri kuwayama1 from lime orchards in central West Mexico

Asian citrus psyllid, Diaphorina citri Kuwayama, is the vector of "Huanglongbing" disease. Different insecticides are used to control the vector by a government containment program to prevent dissemination of disease in citrus growing areas in Mexico. Increased selection pressure on field populations can result in resistance to insecticides. The goal of this study was to determine susceptibility baselines in a laboratory strain of Asian citrus psyllid susceptible to 11 insecticides from five toxicological groups and determine diagnostic doses to test in eight populations from Tahiti lime, Citrus latifolia Tan., and Mexican lime, Citrus aurantifolia Swingle, orchards with different patterns of insecticide use. Resistance ratios were calculated in comparison with data from a susceptible strain in a laboratory in Florida. Most calculated LD50 and LD95 values corresponded well with mortalities caused by diagnostic doses. Asian citrus psyllids from Apatzingan, Michoacan were very resistant to imidacloprid, 4265.6-fold; dimethoate, 106.5-fold; chlorpyriphos, 26.5-fold; and slightly to thiamethoxam, 13.8-fold. At Cofradia de Morelos, Colima, resistance to imidacloprid was 25.6-fold. Resistance to imidacloprid (17.5-fold) and thiamethoxam (12.0-fold) was detected at Cerro de Ortega, Colima. Similar resistance was observed at Tepic, Nayarit, to imidacloprid (13.8-fold) and thiamethoxam (19.3-fold). Psyllids at Casimiro Castillo, Jalisco were resistant to chlorpyriphos (20.6-fold). At El Limon, Jalisco, resistance was found only to thiamethoxam (14.2-fold). Results are similar to those found by Tiwari et al. (2011, 2013) in Florida; however, resistance to neonicotinoids and organophosphates was greater in Asian citrus psyllids in Mexico than those in Florida