Browsing by Author "Castro Quezada, Patricio Salvador"

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Capacidad hospedante de tres especies de solanáceas de la sección lasiocarpa al nematodo agallador de la raíz meloidogyne incognita
(2023) Díaz Granda, Lourdes Elizabeth
Root knot nematode M. incognita is one of the most dangerous and common species affecting Solanaceae family, including the naranjilla crop (S. quitoense). The objective of this work was to evaluate three species of Solanaceas as hosts (S. sessiliflorum, S. hirtum and S. quitoense) for an isolated of M. incognita in greenhouse. Plants of three species were planted in pots and each plant was inoculated with 2500 eggs and second stage juveniles (J2). Host suitability was assessed 80 days after inoculation. Initial inoculum was obtained from infested roots of S. quitoense plants collected in commercial naranjilla orchards. A completely randomized experimental design was used. The variables evaluated at 80 days after inoculation were: gall index (GI), nematode reproduction factor (RF), dry weight of the foliar area, plant height and stem diameter. All species were galled, but S. sessiliflorum and S. hirtum showed the least number of root knots with values of 33.73 and 34.73. Both were classified as resistant / hypersensitive with reproduction factors of 0.94 and 0.85 (RF> 1) respectively, while S. quitoense was susceptible with a value of 1.56. In terms of foliage yield (dry weight), plant height and stem diameter, S. sessiliflorum and S. hirtum showed a tolerance response in relation to S. quitoense.
Caracterización de aislados virales en Solanum quitoense y Solanum lasiocarpum
(Universidad de Cuenca, 2024-01-11) Amón Togra, Henry Luis; Castro Quezada, Patricio Salvador
The cultivation of naranjilla represents one of the significant economic sectors at the level of the eastern communities of Ecuador, being a crop widely accepted both in the national and foreign markets. Among the main limitations that affect production and make it unprofitable are pests and diseases that limit its performance, using excessive use of pesticides to counteract the problems presented in situ. Taking into account the incidence of pests, these can be the main spreaders of more complex diseases such as viruses. In several locations in the Limón-Indanza canton, the incidence of possible symptoms related to viruses has been witnessed, such as: chlorosis, wrinkling of leaves, internerval mosaics, underdevelopment in plants, fruit abortion, highlighting the presence of possible viruses among different locations. The objective of this study was to characterize the viral isolates from 4 naranjilla producing localities in two species of the Lasiocarpa group, (S. quitoense and S. lasiocarpum), mechanical inoculations were carried out in the two species, evaluating the incidence and severity of the symptoms. Observed in the experimental units, a completely randomized design was carried out, for the severity variable it was measured at 15, 35 and 56 dai (days after inoculation), there were differences between the control and the viral isolates for each of the species. It was also identified that S. quitoense was more susceptible to damage than S. lasiocarpum. In the molecular part, no amplifications were observed with the primers used for PCR. In addition, the symptoms observed for each viral isolate were characterized, this work being a contribution of continuity and information for the southern region of the country.
Caracterización de ocho cultivares de tomate riñón hasta su fase de floración bajo cubierta plástica, y evaluación de resistencia al hongo Oidium sp.
(Universidad de Cuenca, 2022-03-20) Anguisaca Prado, Nery Javier; Castro Quezada, Patricio Salvador
In this work, the morphological characterization and the resistance to powdery mildew of eight kidney tomato cultivars (New Yorken, Rodade, Rosa de Berna, Lignon, Caraibo, LA1033, LA3863, Sheila), improved by INRA (National Institute of Agricultural Research) were evaluated. of France), for this it was carried out in the canton of Cuenca, province of Azuay, implanting the cultivation under plastic cover with a completely random design (DCA). The parameters measured in the trial were: emergence percentage, setting percentage, plant height, number of leaves, stem diameter, days to flowering, number of flowers per cluster, number of fruits per cluster, fruit weight, incidence and severity of powdery mildew. The LA1033 and LA3863 cultivars obtained 100% germination, while the yield for the Caraibo cultivar was the lowest with 78%, a lower value than the other varieties whose values were 100%, the LA 1033 cultivar presented higher foliage with an average of 14.44 leaves eighty days after transplanting. The LA3863 cultivar was the earliest for days to flowering with an average of 53.56 days. With regard to powdery mildew, infection occurred only in the Lignon and Rodade cultivars with a severity value of 1.98% for Lignon and 4.8% for Rodade, characterizing them as tolerant, however, the rest of the cultivars have immunity characteristics. in which they were not infected with powdery mildew, in addition, no fruiting was obtained for cultivars LA1033 and LA3863, so their use is not recommended for local conditions.
Caracterización morfológica y molecular del agente causal de la antracnosis en tomate de árbol en Azuay y Loja
(2019) Castro Quezada, Patricio Salvador; Bravo Zúñiga, Catalina; Cabrera Cabrera, Rolendio Anibal; Quillay Curay, Norma; Ramon Montoya, Maria Teresita de jesus; Belesaca Morocho, Ivan Robalino; Diaz Granda, Lourdes Elizabeth
Anthracnose is a fungal disease that causes serious losses in tree tomatoes in Ecuador. This disease causes serious damage to fruits and its control is based mainly on use of chemical products. In Ecuador, the genera Colletotrichum acutatum and Colletotrichum gloeosporioides have been reported to be the causal agent of anthracnose, based on morphological characteristics. In this study, the morphological and molecular characterization of 16 isolates of Colletotrichum spp. of tree tomato, in six different localities in the provinces of Azuay and Loja. Morphological characterization was carried out for variables such as colony color and conidium shape, while molecular characterization was performed by polymerase chain reaction (PCR). PCR experiments was carried out with specific primers reported for C. acutatum and C. gloeosporioides, designed in the internal transcription spacer (ITS). Based on morphological and molecular characterization, it was determined that the causative agent of anthracnose for the provinces of Azuay and Loja is the C. acutatum complex, represented by C. tamarilloi. Isolates presented characteristics of this species and molecular analysis allowed to confirm this result, generating amplifications of molecular weights of approximately 500 bp, while with the specific primers of C. gloeosporioides no amplification was obtained. This molecular characterization confirms results that place the C. acutatum complex as the causative agent of anthracnose in the Southern region of Ecuador.
Comunidades forestales en bosques secundarios alto-andinos (Azuay, Ecuador)
(2017) Vaca Vaca, Carlos Miguel; Castro Quezada, Patricio Salvador; Zea Dávila, Pedro René; Peralta Cornejo, Angel Vicente; Cedillo Tapia, Hugo Alberto; Tepán Vizhco, Braulio Vicente; Toledo Cristian, Jhonson; Jadán Maza, Ángel Oswaldo
In the Andean mountains of southern Ecuador there are areas occupied by high Andean secondary forests as a consequence of anthropic activities. Here we identify different secondary forest communities located over 2900 m a.s.l, based on its floristic similarity. In each community, floristic composition was described by the total exclusive and shared species. Estimation curves were used to provide richness and diversity metrics. The structure was analyzed according to abundance and basal area. In addition, we evaluated the role of environmental variables in floristic conformation and structure through principal components and the redundancy analysis. Three forest communities were identified. Community, located at high altitude and low temperature, had the highest value of diversity and basal area. Variation in species composition was explained by climatic and geographic variables, density by soil and climatic variables, and basal area by topographic variables. Species richness and basal area did not present an altitudinal distribution pattern similar to those from other Andean tropical forests. Therefore, the floristic variation, species richness and basal area seem to be explained by the chronological age of secondary succession, as evidenced by the indicator species belonging to different ecological groups. We concluded that the floristic composition, richness and structure of vegetation in forest communities of high Andean secondary forests are influenced by climatic, topographic, physiographic and geographic variables related to the age of succession.
Conocimiento sobre productos forestales no maderables en dos pisos florísticos: piemontano y montano bajo, en bosque semi-caducifolio, Santa Rufina, Loja – Ecuador
(2017) Castro Quezada, Patricio Salvador; Mora Román, Glenda Isabel; Quizhpe Coronel, Wilson Rodrigo; Jadán Maza, Ángel Oswaldo
Semi-deciduous forest has provided historically non-timber forest products (NTFP) to neighbor populations. However, information about use of their floristic resources is scarce. In this research, we evaluated the state of knowledge of NTFPs for two floristic floors in semi-deciduous forest: Montane and Montane low. We applied semi-structured surveys to investigate the plant uses that provide NTFPs to three age groups. Plant uses were differentiated into nine categories of use. We collected NTFPs at each sampling site where they grow naturally or in home gardens, and then identified taxonomically. We determined the Use Value by use category; the Total Use Value by species, and by species disaggregated by sex and age group. For floristic levels, the food and bev-erage category presented the highest use value. Within the age group of young people in floristic levels, the species belonging to the medicinal category were the most important with similar val-ues for men and women. In adults, in the piedmont level, forage species were the most important, with similar values for men and women. For the elderly, in the two plant formations several species stand out belonging to different categories of uses with similar values. We concluded that knowl-edge about the use is still valid in the three age groups according to the trend of knowledge levels. In the elderly, this knowledge is pragmatic and real, which is transmitted to adults and young peo-ple. In the group of young people, its application is uncertain.
“Determinación de la resistencia a Meloidogyne incognita, en tres especies de la sección Lasiocarpa: Solanum quitoense, Solanum hirtum y Solanum sp.”
(2019-09-06) Pacheco Atariguana, Luis Daniel; Castro Quezada, Patricio Salvador
The naranjilla crop has a great potential in Ecuador, due to its excellent organoleptic characteristics. Nevertheless, the crop has a high susceptibility to attack of nematode Meloydogyne incognita, sometimes occasioning the total loss of crop. This research was carried out under greenhouse and the objectives were: determine the resistance to Meloidogyne incognita, in three species of the Lasiocarpa section: S. quitoense, S. hirtum and Solanum sp; and, find RGAs and SSR molecular markers associated with resistance. For phenotypic analysis, a completely randomized design with five repetitions was used, and for molecular analysis the polymorphism based on absence or presence of amplification products was considered. Nematode inoculum was extracted from roots infected with naranjilla. For molecular analyzes, we used RGAs and SSR primers defined on homology regions for crop resistance genes previously identified. We found that for variables: accumulated biomass, population increase, incidence, index of knotty and severity, results showed highly significant differences between S. hirtum and Solanum sp. with respect to susceptible specie (S. quitoense) at 80 days of evaluation. Regarding the molecular markers, we found two pairs of primers that amplified in S. hirtum and S. quitoense: an RGA defined on an LRR domain and an SSR defined in pepper. No amplifications were obtained in Solanum sp. Furthermore, these primers were found to be polymorphic in the segregating population between S. quitoense and S. hirtum.
Determinación del agente causal de la antracnosis en Annona cherimola (chirimoya) en el cantón Gualaceo provincia del Azuay
(Universidad de Cuenca, 2022-05-09) Álvarez Fajardo, Mélida Lizeth; Tenesaca Bojorque, Diana Andrea; Castro Quezada, Patricio Salvador
Anthracnose is a fungal disease that causes serious losses in the cherimoya crop in Ecuador. The disease causes serious damage to the fruit and its control is mainly based on the use of chemical products. According to studies, Colletotrichum spp. has been reported as the causal agent of anthracnose in cherimoya, but the species has not been defined. In the present study, the morphological characterization and molecular identification of 10 strains of Colletotrichum spp. of cherimoya was carried out in different localities of the province of Azuay. For morphological characterization, the variables evaluated were: colony growth, colony coloration, colony type and conidial shape. For molecular identification, PCR analysis was performed with specific primers reported for C. gloeosporioides and C. acutatum, designed in the internal transcribed spacer (ITS). Based on the morphological characteristics and PCR analysis, it was determined that in Guachapala canton the pathogen responsible for anthracnose corresponds to a complex of C. gloeosporioides and C. acutatum, while in Gualaceo the species causing the disease is C. acutatum.
Diagnóstico de enfermedades virales en Solanum betaceum (tomate de árbol) en los cantones Paute y Guachapala, provincia del Azuay
(Universidad de Cuenca, 2022-03-16) Ávila Proaño, Mariuxi Elizabeth; Bermeo Illescas, José Eduardo; Castro Quezada, Patricio Salvador
In the cantons Guachapala and Paute, Solanum betaceum (tomate de árbol), is a fruit tree highly cultivated, and base of local economy. Just like another crops, the performance of this crop has been affected by different pathogens, such as: bacteria, fungus, etc. In addition to this problems, viral diseases symptoms has been observed, nevertheless, there are not studies that afford to know the etiological origin of theses. This research diagnosed by the molecular and the symptomatic way the phytopatogens viruses in tomato tree in the cantons Guachapala and Paute. Firstly, leaves with the most common symptoms of virosis were collected (chlorosis, mosaics, leaf deformation, blistering and mottling). Then of each tomato producer locality, a viral isolated were obtained and, it was inoculated in healthy seedling plants. The symptoms were development for eight weeks and after that, the morphological and molecular analysis was carried out. Morphological, the incidence and severity of each symptom was analyzed, where the leaf deformation was the symptom with the higher incidence 69,52% follow by blistering 54,35%. In the case of mosaics, chlorosis and mottles, the higher incidence observed was: 49,92%, 50% and 51,36%, respectively. According to the literature, the inducted symptoms by the different viral isolates belongs to viral diseases being the PLRV and PVY the main causals agents of all the analyzed symptoms. With the exception of leaf deformation, the AMV has been related with the others symptoms analyzed, and it is possible that the blistering is the product of the interaction between three causal agents: PLRV, PVY and ToMV. In this study, no one amplification was observed with the primers used.
Drivers of woody dominance across global drylands
(2024) Castro Quezada, Patricio Salvador
Increases in the abundance of woody species have been reported to affect the provisioning of ecosystem services in drylands worldwide. However, it is virtually unknown how multiple biotic and abiotic drivers, such as climate, grazing, and fire, interact to determine woody dominance across global drylands. We conducted a standardized field survey in 304 plots across 25 countries to assess how climatic features, soil properties, grazing, and fire affect woody dominance in dryland rangelands. Precipitation, temperature, and grazing were key determinants of tree and shrub dominance. The effects of grazing were determined not solely by grazing pressure but also by the dominant livestock species. Interactions between soil, climate, and grazing and differences in responses to these factors between trees and shrubs were key to understanding changes in woody dominance. Our findings suggest that projected changes in climate and grazing pressure may increase woody dominance in drylands, altering their structure and functioning.
Efecto del ácido salicílico en la inducción de la resistencia en tomate de árbol (Solanum betaceum) a la antracnosis y caracterización molecular
(Universidad de Cuenca, 2021-01-07) Cabrera Cabrera, Rolendio Anibal; Castro Quezada, Patricio Salvador
The tree tomato (Solanum betaceum) is a species of Andean origin, which has great potential due to its organoleptic characteristics. However, it is very susceptible to the presence of anthracnose whose causal agent belongs to the complex Colletotrichum acutatum. This research was conducted in the field and laboratory. In the field, the effect of salicylic acid (AS) in tree tomato was evaluated against anthracnose. To fulfill this objective, the effect of salicylic acid was evaluated in three concentrations (0.1, 0.2, and 0.4 mM). The application was made directly in the crop. For this, a completely randomized block design with 10 repetitions and a control was used. It was also molecularly characterized 16 strains of Colletotrichum acutatum complex from Azuay and Loja provinces through multilocus analysis by PCR, based on primers defined in actin genes, β-tubulin, and glyceraldehyde 3-phosphate dehydrogenase. The following results were obtained for the effect of AS in resistance induction: 0.2 mM concentration showed significant results when anthracnose severity in fruits was reduced; 0.1 mM concentration had significant effects when anthracnose severity in leaves was reduced in front of control plants and anthracnose incidence in leaves. Besides, the 0.4 mM concentration showed a higher leaf and fruit shedding with contaminated tissue as a defense mechanism against the disease compared to the control. Regarding the molecular analysis by multilocus, it was demonstrated that the species responsible for anthracnose in tree tomato is Colletotrichum tamarilloi, which belongs to the Colletotrichum acutatum complex.
Estado actual del uso de marcadores moleculares en el diagnóstico y control genético de enfermedades de naranjilla
(2021) Castro Quezada, Patricio Salvador; Belesaca Morocho, Ivan Robalino; Díaz Granda, Lourdes Elizabeth
Naranjilla or lulo (Solanum quitoense) is an important native fruit crop to northwestern South America. It is planted mainly in Colombia and Ecuador and is increasingly in demand worldwide. However, it is very susceptible to attack by pests and diseases. In Ecuador, the main pathogens that attack naranjilla are Fusarium oxysporum and Meloidogyne incognita. In addition, a virus of the Tymoviridae family has been detected, which was called Naranjilla chlorotic mosaic virus (NarCMV) and a viru that causes mosaic that has been called Naranjilla mild mosaic virus (NarMMV). Presence of these pathogens has been detected in using different molecular techniques. This report presents the current status in the use of molecular markers, both in diagnosis of diseases and in detection of information related to resistance in naranjilla crop.
Estado actual del uso de marcadores moleculares en el diagnóstico y control genético de enfermedades del tomate de árbol
(2020) Castro Quezada, Patricio Salvador; Palacios Valdiviezo, Manuel Alfonso; Díaz Granda, Lourdes Elizabeth
Tree tomato is a crop of Andean origin. This is cultivated mainly in South America and it is increasingly in demand worldwide. However, it is a crop very susceptible to pests and diseases. There are currently improvement programs to obtain resistant cultivars that include wild species for introgression of features of interest such as disease resistance and improvement of fruit quality in commercial plantations. However, although some segregators of the crosses made have shown resistance in field conditions, the information available regarding molecular markers useful in the interactions of this crop with its main pathogens is scarce. In Ecuador, the main pathogens that attack tree tomatoes are Colletotrichum sp., Meloidogyne sp. and virus species classified in six genera: Potyvirus, Cucumovirus, Tospovirus, Tobamovirus, Potexvirus and Polerovirus. The presence of these pathogens has been detected with the use of different molecular techniques. This report presents the current status in the use of molecule markers, both in the diagnosis of diseases, and in the detection of resistance-related information.
Evaluación de la resistencia a la interacción entre Meloidogyne incognita y Fusarium oxysporum en dos especies de la sección Lasiocarpa: Solanum hirtum y Solanum sp.
(Universidad de Cuenca, 2021-06-01) Reyna Sánchez, Erika Carolina; Castro Quezada, Patricio Salvador
In Ecuador, cultivation of naranjilla crop (Solanum quitoense Lam.) is mainly limited by the nematode Meloidogyne incognita and the fungus Fusarium oxysporum. Interaction between these two pathogens causes low production and in some cases total loss of the crop. This research was carried out with the objective of evaluating the resistance to interaction between M. incognita and F. oxysporum in two species of the Lasiocarpa section: Solanum hirtum and Solanum sp. The study consisted of two phases: first, inoculation of M. incognita and F. oxysporum for three species on greenhouse; and, second, search for molecular markers associated with resistance. For the first phase, seedlings of approximately two months old of S. hirtum, Solanum sp. and S. quitoense (sensitive control) were inoculated with M. incognita and F. oxysporum. A randomized complete block design (DBCA) in a 3x3 factorial arrangement with five repetitions was used. For the second phase, molecular markers SSR and RGAs associated with resistance were analyzed in the Molecular Biology Laboratory of the University of Cuenca for parents and a segregating population of S. hirtum x S. quitoense cross. The results showed indicate that S. hirtum and Solanum sp. obtained the best performances in terms of the variables accumulated biomass, height, stem diameter, degree of discoloration and degree of severity of wilting, since they presented significant differences compared to the sensitive control S. quitoense. Two SSR markers and four RGAs markers based on resistance genes showed polymorphism. They amplified only in S. hirtum, and presented polymorphism in the segregating population of the S. hirtum x S. quitoense cross.
Evaluación de la resistencia de seis variedades de trigo (Triticum aestivum L.) a tres cepas de Fusarium spp.
(Universidad de Cuenca, 2022-12-07) Padilla Romero, Byron Mauricio; Castro Quezada, Patricio Salvador
In Ecuador, one of the factors that limit wheat production are diseases, one of the most important being the disease called “fusariosis” of the ear of wheat. This disease is caused by various species of the fungus Fusarium spp. This disease is of great economic importance because it can reduce production by more than 50%. The present research work was carried out in a greenhouse, in order to evaluate the resistance of six wheat varieties previously described as resistant to infection by three strains of Fusarium spp. The morphological characterization of the strains was carried out based on taxonomic keys and for molecular identification, PCR was used through the use of specific primers for Fusarium graminearum, defined in the galacto oxidase gene (gaoA). Punctual inoculation of three strains of Fusarium spp., was carried out in wheat ears at the anthesis stage. All the wheat varieties evaluated presented a reaction of resistance to Fusarium, also the three strains of Fusarium spp. were able to infect all wheat cultivars and induced the characteristic symptoms of Fusarium head blight (TEF). There were highly significant differences between the strains regarding the measurement of the incidence and severity variables. According to the cultural and morphological characteristics observed in carnation leaf agar medium (CLA), the three strains were identified within the genus Fusarium, but it was not possible to confirm to which species they belonged. There was no PCR amplification with the specific primers designed for F. graminearum.
Evaluación de resistencia a la interacción entre Meloidogyne incognita y Fusarium oxysporum en una población segregante de la cruza entre Solanum quitoense y Solanum lasiocarpum
(Universidad de Cuenca, 2024-05-08) Ramírez Bermeo, Oscar Andrés; Campos Urgilez, Liz Lorena; Castro Quezada, Patricio Salvador
The cultivation of naranjilla (Solanum quitoense Lam.) represents one of the most important economic activities for a large number of communities in Ecuador. This crop is limited mainly by the affection of certain pathogens such as the nematodes Meloidogyne incognita together with the fungus Fusarium oxysporum, which are responsible for the deterioration in the development of the plants already established in the field. For this reason, the following study aims to evaluate a population of segregants of the cross between S. quitoense and the wild species S. lasiocarpum reported as resistant to the interaction between M. incognita and F. oxysporum, to determine the level of damage and to evaluate microsatellite molecular markers and RGAs. This research was carried out in two stages: a greenhouse stage in which the segregants infected with pathogens were evaluated after 90 days, where damage was analyzed at the morphological level; and a stage in the Biotechnology laboratory of the Faculty of Agricultural Sciences, in which different combinations of primers associated with resistance in other solanaceae were tested. The first phase involved inoculations in 12 populations (10 segregants, S. quitoense and S. lasiocarpum). A completely randomized design (CRD) was used in a 4x12 factorial arrangement, with four replications. The second phase was carried out in the laboratory where SSR and RGA molecular markers associated with resistance were analyzed for both the parents and the 10 segregating populations resulting from the cross between S. quitoense and S. lasiocarpum. According to the results obtained, it was observed that certain segregants and the parental S. lasiocarpum obtained the best results, since they showed significant differences compared to S. quitoense, the latter being susceptible compared to the other populations. As for molecular analysis, no amplifications were observed with the primers used for PCR
Evaluación in vitro de biofungicidas y ácido salicílico frente a fungicidas químicos para el control de antracnosis en tomate de árbol
(Universidad de Cuenca, 2023-05-30) Torres Gómez, María José; Castro Quezada, Patricio Salvador
Anthracnose known as "chicken eye", caused by the phytopathogenic fungus Colletotrichum sp, which is widely distributed in production areas, is the most important disease, since the pathogen not only attacks the fruit at any phenological stage but also the leaves, branches and inflorescences, thus reducing the productive life of the tree by up to 50%. The aim of the present investigation was to evaluate, under in vitro conditions, biofungicides and salicylic acid against chemical products for the control of anthracnose in tree tomato. Samples were taken from 12 farms distributed in the provinces of Azuay, Loja and Cañar. For the collection, the fruits presented the characteristics of the disease as black lesions, accompanied by masses of pink conidia. These samples were subjected to isolation and purification for inhibition tests. The treatments evaluated were salicylic acid 0.4mM, Bacillus subtilis 5ml/L, Bacillus pumilus 5ml/L, pyraclostrobin 13.3% + epoxiconazole 5% 1ml/L, captan 1g/L, difenoconazole 0.75ml/L, and iprodione 1ml/L plus a control treatment. At the in vitro level, salicylic acid inhibited mycelial growth of Colletotrichum sp. from samples collected in the provinces of Azuay, Loja and Cañar, while the T5 treatment (captan) inhibited mycelial growth in samples from Azuay and Loja in the localities of Don Julo, Urdaneta and Saraguro.
Evaluación in vitro y en campo de la patogenicidad de Moniliophthora roreri en mazorcas de cacao de la variedad Ramilla, en un período de 60 días
(Universidad de Cuenca, 2025-08-08) Ruiz Álvarez, Zayetzi Anabel; Sánchez Guzmán, Fátima Anabel; Castro Quezada, Patricio Salvador
Cocoa faces several phytosanitary challenges that affect its yield and quality, especially moniliasis, caused by the fungus Moniliophthora roreri that causes serious damage between 30% and 100% of the fruits. As a short-term solution to this problem, different clones such as Ramilla or CCN-51 have been developed to ensure the survival of the Ecuadorian cocoa industry. In this context, this research seeks to generate valuable information on the behavior of the fungus in the field of pathogenicity and its impact on the crop, considering that there are few studies on the subject, for which two scenarios were proposed, one in the field and another in vitro where 4 treatments were applied, differing in the time that elapsed after the sporulation of the fungus, that is to say 15, 30 and 45 days after sporulation, each one with 5 repetitions, obtaining as results that the time of sporulation that the fungus has at the moment of infection influences its pathogenic capacity. The treatment with the youngest fungus (T1), presented greater severity in the colonization of the host, compared to the other treatments, both in vitro and in the field, in terms of survival and competition with other microorganisms, the treatment that showed greater effectiveness was treatment T3, because the more mature the spores, the better they tolerate damage and changes in their environment.
Grazing and ecosystem service delivery in global drylands.
(2022) Castro Quezada, Patricio Salvador; Jadán Maza, Ángel Oswaldo
Grazing represents the most extensive use of land worldwide. Yet its impacts on ecosystem services remain uncertain because pervasive interactions between grazing pressure, climate, soil properties, and biodiversity may occur but have never been addressed simultaneously. Using a standardized survey at 98 sites across six continents, we show that interactions between grazing pressure, climate, soil, and biodiversity are critical to explain the delivery of fundamental ecosystem services across drylands worldwide. Increasing grazing pressure reduced ecosystem service delivery in warmer and speciespoor drylands, whereas positive effects of grazing were observed in colder and species-rich areas. Considering interactions between grazing and local abiotic and biotic factors is key for understanding the fate of dryland ecosystems under climate change and increasing human pressure.
Hotspots of biogeochemical activity linked to aridity and plant traits across global drylands
(2024) Castro Quezada, Patricio Salvador; Jadán Maza, Ángel Oswaldo
Perennial plants create productive and biodiverse hotspots, known as fertileislands, beneath their canopies. These hotspots largely determine thestructure and functioning of drylands worldwide. Despite their ubiquity, thefactors controlling fertile islands under conditions of contrasting grazingby livestock, the most prevalent land use in drylands, remain virtuallyunknown. Here we evaluated the relative importance of grazing pressureand herbivore type, climate and plant functional traits on 24 soil physicaland chemical attributes that represent proxies of key ecosystem servicesrelated to decomposition, soil fertility, and soil and water conservation. Todo this, we conducted a standardized global survey of 288 plots at 88 sites in25 countries worldwide. We show that aridity and plant traits are the majorfactors associated with the magnitude of plant effects on fertile islands ingrazed drylands worldwide. Grazing pressure had little influence on thecapacity of plants to support fertile islands. Taller and wider shrubs andgrasses supported stronger island effects. Stable and functional soils tendedto be linked to species-rich sites with taller plants. Together, our findingsdispel the notion that grazing pressure or herbivore type are linked to theformation or intensification of fertile islands in drylands. Rather, our studysuggests that changes in aridity, and processes that alter island identityand therefore plant traits, will have marked effects on how perennialplants support and maintain the functioning of drylands in a more aridand grazed world.