Agronomía Mesoamericana

50th anniversary of the Center for Research in Grains and Seeds (CIGRAS): History and contributions in research, teaching, and social work

2022-09-16T00:50:07-06:00

Bacterial coinfections on foliar blight and bulb rot in onion (Allium cepa L.)

2022-10-03T11:10:38-06:00

Introduction. The onion bulb (Allium cepa L.) is a cultivated vegetable characterized by its fleshy scales susceptible to phytopathogen attacks causing economic losses. The symptoms of foliar wilting, blighting, and rot of bulb can be caused by different genera and bacterial species that can co-infect the host, making it difficult to identify the causal agent. Objective. To evaluate the effect of bacterial co-infections on foliar wilt and bulb rot in onion. Materials and methods. The bacteria were isolated from onion plants with symptoms of leaf blight and bulb rot, from crops located in Choachí Cundinamarca, Colombia, collected in June 2018. Bacterial isolates were purified, identified, and inoculated individually and in a mixture on healthy onion leaves and bulbs. Six treatments per organ were evaluated: three with individual infections and three with co-infection. The lesion progress was measured in both organs for twelve days after inoculation. Results. Two bacterial species identified as Pantoea ananatis and Rahnella aquatilis were obtained from the foliar and bulb symptoms. In individual infections, the P. ananatis strain presented the highest virulence causing 34.29 % bulb damage, and 100 % leaf damage, while the R. aquatilis generated the lowest percentage of rotting in the bulb (8.87 %) and it did not produce wilt. In co-infections, the combination of P. ananatis and R. aquatilis produced the lowest percentages of bulb (15 %) and leaf (10 %) damage, associated with a decrease in the symptom’s expression. Conclusion. R. aquatilis acted as an antagonistic organism of P. ananatis and causes a delay in the development of foliar wilt and bulb rot symptoms in onion.

olletotrichum species associated with anthracnose in orange (Citrus sinensis (L.) Osb.) and its in vitro control with fungicides

2022-08-29T15:05:44-06:00

Introduction. Orange (Citrus sinensis (L.) Osb.) cultivation is one of the most important worldwide. Among the main limitations in its production is the fall of flowers caused by Colletotrichum. Objective. To determine the species of Colletotrichum associated with anthracnose in orange and to estimate the in vitro effectiveness of four fungicides on its control. Materials and methods. This study was carried out between June 2021 and February 2022. Six fungal isolates, obtained from orange floral tissues, were identified via polymerase chain reaction (PCR). The efficacy of the fungicides tebuconazole, pyraclostrobin, difenoconazole, and ferbam on two Colletotrichum isolates was evaluated. Two tests were carried out to determine the degree of inhibition of mycelial growth and the percentage of effectiveness of each fungicide. Results. Colletotrichum abscissum was identified on petals with symptoms and Colletotrichum gloeosporioides on calyxes. The effectiveness of the doses used of the fungicides tebuconazole and difenoconazole was verified by presenting inhibition of mycelial growth from a tenth of the commercial dose evaluated. Pyraclostrobin showed little control over both isolates. Ferbam did not present an efficient control in any of the doses evaluated in both strains. Conclusion. The fungi associated with anthracnose in orange, on the farm studied, were C. abscissum, present on petals with initial and advanced symptoms, and C. gloeosporioides present on persistent calyxes. The effectiveness of the fungicides evaluated was higher for triazoles, tebuconazole, and difenoconazole, in that order. Pyraclostrobin showed a poor control on both isolates. Ferbam was not effective in in vitro tests.

Detection of Duponchelia fovealis Zeller with pheromones in strawberry farms of Costa Rica

2022-08-19T10:19:52-06:00

Introduction. Duponchelia fovealis Z. is a pest of production crops in Europe and in the United States. It has recently been detected in strawberry production in Brazil, Mexico, and in a farm in the Vásquez de Coronado canton, San José, Costa Rica. Objective. To determine the presence and distribution of Duponchelia fovealis Z. in strawberry farms in Costa Rica. Materials and methods. During the dry seasons of 2020-2021 and 2021- 2022, traps baited with the D. fovealis pheromone were placed in the initially reported farm in Vásquez de Coronado and in six other farms located in the main strawberry regions of Costa Rica: La Cima of Dota, Llano Grande, Poás, and Vara Blanca. Results. The monitoring showed that the highest populations were established in the Vásquez de Coronado farm, while occasional captures were obtained in farms such as La Cima of Dota in San José and two in Llano Grande in Cartago. Conclusions. The presence of D. fovealis Z. in Costa Rica was determined, with limited distribution. Given this, an analysis of the risk of the pest and the implementation of measures to reduce the insect’s dispersal are suggested.

Substrate and spatial planting pattern on the productivity of clonal mini gardens of Tectona grandis Linn. F

2022-08-03T11:24:46-06:00

Introduction. Tectona grandis is the species with the largest planted area in Costa Rica, due to the high prices in the international market. The production of plants for reforestation has been technified in the country and is currently being developed based on protected environment technologies, which increase productivity, reduce operating costs, and offer planting material throughout the year. Objective. To evaluate the effect of two substrates and five planting densities on the productivity of clonal mini-gardens of Tectona grandis in a protected environment. Materials and methods. Four readily available inert substrates were characterized by granulometry and moisture retention analysis, from which stone dust was selected as the optimum substrate. An experimental trial with a 2x5 factorial design was established in San Carlos, Costa Rica to evaluate two substrates (stone dust alone and with 25 % charcoal) and five planting densities (cm) of 10x10, 10x5, 7x5, 10x10 with two plants per hole and 10x10 with one plant in the middle. Each density had four clones as a replicate effect. The trial was evaluated during five continuous production cycles from January to September 2021. Results. The use of stone dust as substrate, without charcoal, recorded the highest productivity at a lower cost. The spatial planting arrangement of 10x10 cm with one plant in the middle (n=145 plants/m²), recorded the highest shoot production per mother plant (1.16). The 7x5 cm arrangement increased productivity by up to 206 shoots m²/month. Conclusion. The change in planting density of the clonal mini-garden, in a first stage to 10x10cm with an additional plant in the center, resulted in a high impact on productivity (74 %), greater efficiency in the use of space, and a better gradual change in the operating system.

Refreshing whey drink with the addition of rice flour and orange flavor

2022-08-24T14:42:16-06:00

Introduction. Whey is the residual liquid product of the manufacture of cheese with useful nutritional value. It contains 95 % of the lactose, 25 % of the proteins and 8 % of fat of the total milk components. Objective. To elaborate a refreshing whey drink with the addition of rice flour and orange concentrate. Materials and methods. The experimental work was realized at Food Department laboratories belongs to Pharmacy and Foods Institute from Universidad de La Habana-Cuba, between January and May 2021. The raw materials: whey, rice flower, and orange concentrated juice were characterized. A mix design was applied using Design–expert version 8.0 program to get the better formulation (combination of ingredients). The independent variables in percentage were: whey (79.95 to 84.15), concentrated orange juice (7 to 11), and guar gum stabilizer (from 0.1 to 0.3), and as response variables, acceptability and stability of the obtained drink. The best combination of ingredients was evaluated by a panel of judges based on the intensity of the odor, orange flavor, and consistency, using the attibutes “light”, “moderate” and “marked”. Results. The best formulation was composed of whey (84.15 %), orange concentrate (7 %), refined sugar (5 %), rice flour (3.75 %), and guar gum stabilizer (0.1 %). The sensorial acceptability criteria given by the training judges was “I like it”. Regarding the intensity of the orange smell, the whey beverage received a balanced criteria between the “light” and “moderate” ratings and the consistency was qualified as “light”. Conclusions. All formulations tested showed good stability and adequate sensory acceptability. The best combination showed no phase separation at 24 hours after processing and was characterized by twenty tasters.

Semen analysis in precision farming in the 21st century

2022-08-24T11:07:21-06:00

Introduction. Assisted reproduction of animals traces its origins in the domestication of livestock species useful to humans. The consequent artificial selection processes allowed the development of biotechnological techniques that contributed to the improvement of animal production capacities. Objective. To contextualize the seminal analysis in precision farming in the 21st century. Development. The visualization of spermatozoa under the microscope can be considered as the first step in the advent of reproductive biotechnology and the basis for the development of assisted reproductive techniques. With the improvement of microscopy methods, it was possible to characterize male gametes, which meant a significant advance in artificial insemination technology. The turning point marked by the development of sperm conservation techniques implied a substantive change in the development of these technologies in livestock species, either with cryopreserved or refrigerated semen. These methods are of high value in the case of threatened species since germplasm banks can be created for genetic conservation and rescue of species at risk of extinction. Semen analysis has been developed alongside with assisted reproduction techniques and today it is considered a relevant technique in animal reproduction biotechnology, which has been perfected through the advancement of science and technology, optical physics, and computing. Conclusion. Seminal analysis has undergone a paradigm shift by rejecting obsolete techniques of subjective evaluation of semen quality and adopting objective methods of semen evaluation, through the analysis of large volumes of data and motility, kinematics, morphometrics, morphological, and DNA fragmentation variables, which allow a better characterization of the ejaculates of breeders in artificial insemination centers.

Physicochemical and sensory characteristics of a caprine milk caramel with the inclusion of amaretto

2022-07-26T09:25:58-06:00

Introduction. Worldwide, bovine dairy products are prevalent, so there is a need for studies focused on less traditional milk, such as goat milk. Objective. To evaluate the effect of two levels of inclusion of amaretto on the physicochemical and sensory characteristics of a goat milk caramel. Materials and methods. Between January and September 2017, at the Universidad de Costa Rica, milk caramels were made with two proportions (6 % and 9 %) of amaretto, which were selected using two focus groups, pH, Brix degrees, aw, texture, color, and sensory liking were evaluated. Results. The milk caramels with inclusion of 6 % and 9 % amaretto obtained the following characteristics respectively: 71.8 and 70.8 ºBrix, pH= 6.8 and 6.9, aw=0.8, hardness= 1.3 and 0.3, adhesiveness= 0.75 and 6.0, elasticity= 23.0 and 21.0, L*= 33.0 and 33.4, a*= 11.3 and 11.4, b*= 26.2, c*= 28.5 and 28.6, h*= 66.7 and 66.4, with an average liking of 7.3 and 7.7, and an average purchase intention of 6.9 and 7.2. The cluster analysis generated three groups of people: G1 = 25.5 % with a mean liking of 4.7 and 6.2 for the 6 % and 9 % formulations, respectively; G2 = 19.6 % with a mean liking of 8.5 and 5.5 for the 6 % and 9 % formulations, respectively; and G3 = 54.9 % with a mean liking of 8.2 and 9.1 for the 6 % and 9 % formulations, respectively. Conclusions. The inclusion of amaretto in the goat milk caramel turned out to be the product with the best profile. No significant differences were observed between the two liquor inclusion levels. The results suggest that both products had appropriate technical characteristics and taste.

Traceability in the agricultural sector: A review for the period 2017 – 2022

2022-07-26T10:23:44-06:00

Introduction. Traceability is regarded in business systems as a monitoring and control tool that is centered on measuring and gathering data for efficient resource allocation. The agricultural sector is no stranger to this practice because, like other industrial systems, it integrates control needs at the level of cultivation, supply of inputs, transformation, transportation, and marketing of products. Objective. To identify objects and scopes of monitoring, analysis units, and adoption of traceability trends in the agricultural supply chain, in order to reference the development of recent studies and publications that integrate this control function in this sector. Development. The applied methodology was developed through the search, selection, and analysis of articles in scientific repositories such as Science Direct and AGRIS, to identify trends in agricultural traceability in the years 2017 to 2022. Application and integration trends of traceability systems were recognized in the agricultural sector around different approaches, including digitization and information security, measurement of agricultural productivity and environmental impact mainly within the concept of sustainability. Lines of research are presented in its conclusions, as well as the knowledge gaps for future work. Conclusions. The results of the review in the last six years frame traceability trends mainly in the digital monitoring of cultivation processes, the measurement of productivity, and the environmental impact. The degree of direct intervention in the producer represents the highest proportion in the category of the logistic scope of traceability. Therefore, it is recommended in the future the development of traceability systems that monitor productivity, environmental, and social impact indicators in a convergent manner, as well as the integrated participations of actors in the agricultural sector, including producers, technical advisors, and government entities.

Autochthonous microorganisms as an alternative for the biofertilization of Glycine max (L.) Merrill

2022-10-11T07:53:04-06:00

Introduction. Soybean (Glycine max (L.) Merrill) has economic and nutritional importance due to its protein levels and vegetable oil content of biological quality, necessary for human and animal feed. The microbial alternatives for biofertilization of this crop would represent an option for its production with low inputs in tropical conditions. Objective. To evaluate the effect of autochthonous microorganisms (MA) as an alternative for biofertilization of G. max under low-input production conditions. Materials and methods. The experiment was established in a farm located in the town of El Coco, Yara, Granma, Cuba, on a Carbonated Fluffy Brown soil, during the year 2021. Certified G. max cv. Incasoy-27 seeds were used. Sowing was carried out in spring at a distance of 0.70 m x 0.04 m. Three doses of MA (12, 24, and 36 L ha^-1) and an absolute control where used. Variables of growth, yield, and their components were evaluated. A randomized block design was used. Data were processed by ANOVA, linear regression, correlation, and principal component analysis. Results. The MA biostimulated the growth of G. max in a range of 12 % and 24 %, while the yield was favored between 16 % and 44 %. Pearson’s correlation analysis indicated that the seeds mass per plant and number of pods per plant were the variables most strongly interrelated with yield. Conclusion. The inclusion of MA achieved a biostimulation of plants length growth of G. max cv. Incasoy-27 compared to the control and the agricultural yield was enhanced.

Physico-chemical and sensory characterization of two rice (Oryza sativa) varieties during aging process

2022-10-25T10:36:51-06:00

Introduction. Once harvested, paddy rice is stored in aerated silos for temperature control, which is known as rice aging. During aging, physicochemical, and physiological changes occur in the rice grain, these changes affect its culinary quality. Objective. To determine the effect of aging time on the physicochemical and sensory characteristics of two rice varieties. Materials and methods. This study was carried out in Agrifood Science Faculty Laboratories of the Universidad de Costa Rica, between September 2018 and March 2019. The two rice varieties studied were grown in Osa, Puntarenas. The first cv. Lazarroz FL, indica type, and the second cv. UCR-168-10, aromatic type were stored for 4.5 months. During storage, total starch, resistant starch, amylose, moisture, protein, was determined, and sensory attributes were evaluated with a trained sensory panel. Results. The two rice varieties studied don’t show significant differences during 4.5 months of storage in moisture, total starch, and resistant starch. Amylose content showed variation without a clear trend. Protein content was reduced during aging until 2,5 months of storage. According to the sensory test, attributes such as integral flavor and stickiness did not show significant differences throughout the study, while the remaining parameters did, either over time or between varieties. Cooked rice appearance showed an improvement up to 2,5 months aging for the two varieties. Whiteness of rice increased for both varieties during aging. Conclusion. Storing rice for 2,5 months achieved the desired changes in protein and sensory attributes for the rice varieties evaluated.

Quantification of the percentage of total broken grain in rice (Oryza sativa L.) by digital image analysis

2022-08-11T15:26:43-06:00

Introduction. Digital image analysis (DIA) can be used to evaluate the quality parameters of rice grains, such as the percentage of whole grain. Objective. To quantify percentage of total broken grain by means of digital image analysis (DIA) applied to the quantification of rice (Oryza sativa L.) quality. Materials and methods. The present work was developed in facilities of the Centro para Investigaciones en Granos y Semillas (CIGRAS) of the Universidad de Costa Rica (UCR), Costa Rica, in 2021. The work was carried out with commercial rice samples. A sample plate was developed to facilitate the arrangement of the grains and to acquire the digital images. The length parameters established in the technical regulation of Costa Rica RTCR 202:1998 were used to quantify the percentages of small broken, broken grains, and whole grains, which were quantified conventionally and by means of digital images. The DIA included the segmentation and binarization process of the objects (small broken, broken grains, and whole grain) to quantify their areas and catalog the digitally identified elements in weight values. Results. It was possible to quantified the percentage of small broken and broken grain with DIA. The correlation between the variables quantified by DIA and those evaluated conventionally was greater than 0.93 for the small broken property and 0.98 for broken grain. Conventional analysis requires 1 to 2 hours to determine the percentage of total broken grain and other quality properties in each rice sample. The digital analysis requires 7 to 23 minutes per sample plate to analyze all the properties evaluated (small broken and broken grain). Conclusions. The digital analysis method applied allowed to determine the total broken grain properties in samples composed of hundreds of grains.

Morphology and viability test optimization in seeds of Passiflora spp. from Costa Rica

2022-10-15T09:03:53-06:00

Introduction. In Costa Rica there are 51 native species of passion fruit plants that have commercial potential due to their phytochemical characteristics. In Passiflora the seminal characteristics can be used to taxonomically classify the genus species. The identification of plant material and the development of methodologies that enable quality assessment is essential for propagation, production, and conservation. Objective. To characterize Passiflora biflora and Passiflora adenopoda seeds based on their morphology and to optimize the protocol for determining their viability by means of the tetrazolium test. Materials and methods. Morphological characterization and viability trials were carried out in 2022, at the Centro de Investigaciones en Granos y Semillas (CIGRAS), Universidad de Costa Rica. Twelve external morphological characters and the internal structures of P. biflora and P. adenopoda were characterized. For the optimization of the tetrazolium test protocol, the effect of two types of cutting (longitudinal and angular), two concentrations of tetrazolium salt (0.5 % and 1 %), three temperatures (30, 35, and 40 ºC), and four incubation times (3, 6, 12, and 24 h) were assessed. Results. The morphological characters evaluated allowed the seeds to be classified as P. biflora and P. adenopoda. By using 1 % tetrazolium salt, a longitudinal cut, a temperature of 40 ºC, and an incubation time of 3 h, similar viability percentage was obtained (90 % in P. biflora and 91 % in P. adenopoda), and a staining of the same quality, as that obtained with the international standardized method. Conclusions. The seminal characteristics assessed allowed the classification of the analyzed seeds as P. biflora and P. adenopoda. In addition, the tetrazolium test protocol was optimized by reducing the incubation time from 24 to 3 hours.

Physiological seed quality of carrot (Daucus carota L.) assessed by vigor testing

2022-10-20T09:04:29-06:00

Introduction. In carrot cultivation direct sowing is practiced because the seedling cannot resist the stress of transplanting. It is essential to use seeds that germinate in a maximum of seven days and uniformly. Seeds vigor is associated with yield performance in the field and, at the international level there are different test to measure it. However, in carrot, the methodologies are still scarce and are not standardized. Objective. To determine the physiological quality in seeds of two varieties of carrot (Daucus carota L.) by mean of vigor tests. Materials and methods. This research was carried out at the Centro para Investigaciones en Granos y Semillas (CIGRAS) of the Universidad de Costa Rica in 2018. Seeds of Bangor and Triunfo varieties with moisture percentages of 7 %, 10 %, and 13 % were used. The vigor tests used were the following: radicle protrusion, first germination count (seven days), accelerated aging, electrical conductivity, and the germination analysis by digital images. Pearson’s correlation analyses were performed between the variables studied. Results. Significant correlation coefficients (Pearson’s r) were observed for electrical conductivity with variables obtained from the image analysis: t10 (r=0.83), t50 (r=0.87), and the area under the curve (r=-0.72). Trough the electrical conductivity test, it was determined that the Bangor lot had greater vigor than the Triunfo lot (Tukey, p≤0.05). Conclusions. The analysis of digital images and the electrical conductivity tests allowed measuring the vigor in seed lots of Bangor and Triunfo varieties, and complementing them with germination results to determine their physiological quality.

Egg quality and productive performance of ISA Brown laying hens with grazing access

2022-10-14T08:54:33-06:00

Introduction. Egg production systems are critical to food security. Concerns about animal welfare are increasing the interest in egg production systems with access to grazing. Objective. To describe the productive performances, morphological characteristics, and nutritional quality of the eggs from laying hens of the Isa Brown genetic line in a floor system with access to grazing. Materials and Methods. The research was carried out between July 2018 and January 2020 in the central canton of Turrialba, Cartago, Costa Rica, with hens of the Isa Brown genetic line with access to grazing. Productive performances were compared with the standard of the genetic line. External and internal morphological variables of the egg were evaluated and its nutritional content (dry matter, crude protein, ethereal extract, ash, calcium, phosphorus, saturated fatty acids (SFA), monounsaturated (MUFA), and polyunsaturated (PUFA) was characterized in hens of different ages. Results. The productive performances was not different from the genetic standard. The increase in bird age had a statistically significant influence on the increase in egg and shell weight, and the decrease in morphological index. Nutritional analysis indicated that increasing hen age decreased the dry matter content and the concentration of SFA and MUFA in the egg. The PUFA/SFA ratio of the eggs was higher than 0.45, regardless of the age of the laying hen. Conclusion. The productive indicators of the hens with access to grazing did not differ from ISA Brown genetic line standards for alternative systems. Egg weight, yolk index, Haugh units, and morphology index varied with the age of the hen.

Phenological observations, oil characteristics and equilibrium isotherm of Myroxylon peruiferum seeds (Fabaceae)

2022-09-26T08:55:27-06:00

Introduction. Phenological information on Myroxylon peruiferum in Costa Rica is scarce. In addition, the characteristics of the oil and the equilibrium isotherm are unknown. The knowledge generated in this field will allow proper seed management and generate oil prospecting options. Objectives. (i) To document a flowering and fruiting event of a single M. peruiferum tree. (ii) To determine the characteristics of the fruit and seed oil. (iii) To generate a water absorption/de-absorption isotherm. Materials and methods. From March to May 2021, the flowering and fruiting of M. peruiferum tree was documented in Montes de Oca, San Jose, Costa Rica. Mature fruits were collected between June and July. The oil content of fruits and seeds was characterized separately. A water absorption/de-absorption isotherm was elaborated, with which the fit of the Cromarty equation was tested. Results. The flowering, fruiting, and dispersal period lasted five months. These phenophases occurred simultaneously. Oleic acid was the main fatty acid. There was a significant correlation between the percentages of fatty acid in the fruit and seed oil, and between the contents of saturated, monounsaturated, and polyunsaturated fatty acids. The oil is yellow, moderately intense, and luminous. As relative humidity increased, seed moisture content also increased. The linear relationship between the actual values and those obtained using the Cromarty equation was R²= 0.93. Conclusion. Mature fruit can be harvested between March and August, and be used for germination, propagation and oil prospecting studies. Once the relationship between relative humidity and seed moisture content is established, studies on seed storage and viability loss can be developed.

Comparison of fecal near-infrared with conventional methods to estimate intake and digestibility in sheep

2022-08-29T11:06:10-06:00

Introduction. Intake and digestibility are parameters that define the quality of a forage; however, they are difficult and expensive to estimate. Near infrared spectroscopy technology applied to feces (NIRSf) is an alternative to conventional reference methods to estimate dry matter voluntary intake (DMVI) and digestibility (DMD) in sheep. Objective. To compare NIRSf technology with conventional methods for estimation of DMVI and DMD in confinement sheep. Materials and methods. Six bioassays were carried out at the Tibaitata research center, Cundinamarca, Colombia, during 2019 and 2021 with five sheep (LW 58.28±11 kg) to estimate DMVI and DMD by three methods: gravimetry, markers and NIRSf. The animals were fed six diets contrasting in their nutritional value. Forage and feces samples were collected, dried, and ground for subsequent chemical and spectral analysis. Results. The estimation of DMVI and DMD was different (p<0.001) in the six evaluated feeding regimenes, where the DMVIMW ranged from 37.54 to 82.58 g/kg LW0.75, and the DMD ranged from 36.32 to 58.81 %. In the comparison of the estimation of DMVI and DMD by the referent method (gravimetric) with marker and NIRSf methods, shows that the NIRSf method presented a better adjustment compared to the marker method, presenting less root mean square error value (-1.53 and -1.75, respectively), lower mean absolute error (-3.01 and -0.5, respectively), and higher determination coefficient (+0.09 and +0.28, respectively). Conclusion. The estimation of the DMVI and the DMD by means of the NIRSf equations presented a better fit compared to the marker method, however, it is necessary to improve the accuracy of the calibrations using feces samples from animals under different productive contexts.

Bioactive compounds in cheeses: biosynthesis, biological activity, and contribution of lactic acid bacteria

2022-07-20T08:13:48-06:00

Introduction. Since 1990, there has been an increase in the rate of diseases associated with unhealthy diets and sedentary lifestyles, whose care is a challenge for health systems. This has aroused interest in functional foods, i.e., those that in addition to providing macro and micronutrients, provide substances that have a physiological effect on the body, which translates into improving the health of those who ingest them. Generically, these compounds are known as bioactives. Objective. To review the main bioactive substances reported in cheeses, as well as the role of microorganisms in their production and the biosynthetic routes of the main compounds. Development. Milk and its derivatives are food products consumed around the world and show a constant increase in their production and consumption. This market trend is due to its flavor and nutritional value. One of the most demanded dairy products in the world are cheeses. They are a source of substances such as peptides, fatty acids, vitamins, bacteriocins, organic acids, gamma aminobutyric acid, etc. all with important biological activity. Conclusion. The presence, quantity, and availability of the bioactive compounds present in the cheeses differ, as a result of the type of milk used for its elaboration, the type of microorganism used, either as starter or secondary culture, as well as the technological process employed.

Fast seed histology protocols: Benzene derivatives-free vs xylene-dependent

2022-10-06T09:03:37-06:00

Introduction. Seeds are complex structures that allow the biological and crop propagation of plants. Seed histology can be used for teaching, researching, and for pathological diagnostic. Histology protocols are commonly divided into 5 different stages: fixation, processing, cutting, staining, and mounting. Xylene is a dangerous reagent used during the processing, staining, and mounting of histological specimens that can contaminate the environment and is toxic for users. Objective. To compare two new protocols for seed histology accelerated with microwave, tested on seeds of economic importance species. Materials and methods. The experiments were done between January and May of 2022 at the Centro de Investigaciones en Granos y Semillas (CIGRAS) of the Universidad de Costa Rica. The compared protocols were: a benzene derivatives-free (BDF) and a xylene-dependent (XD). Seeds of Carica papaya L. (Caricaceae) var. Pococí, Coffea arabica L. (Rubiaceae) var. Obata, Glycine max L. (Fabaceae) var. CIGRAS-06, Phaseolus vulgaris L. (Fabaceae) var. Tayni, Oryza sativa L. (Poaceae) var. Lazarroz FL, and Zea mays L. (Poaceae) var. EJN-2 were used. Three technical replicates of five seeds of each species were tested with the XD and BDF protocols, on different days each replicate. Results. The photomicrographs obtained with both protocols showed that the samples maintained the morphology integrity of embryo, endosperm or cotyledons, and other seed structures. BDF and XD protocols produced seed histology slides and microphotographs. PAS-Coomassie Blue staining made a good differentiation of carbohydrates and proteins. Fastness of both protocols is a benefit compared with other protocols for plant histology that can take several days or even weeks. Conclusions. The BDF and XD protocols were suitable for seed histology analysis of bean, coffee, maize, papaya, and soybean, slides were obtained in less than 5 hours. BDF protocol is the first for plant tissue processing that does not use benzene derivatives and that uses paraffin as embedding medium.

Nutritional contribution and sensory profile of panettone enriched with almonds, raisins and dehydrated blueberries

2022-10-25T08:56:39-06:00

Introduction. In Peru, panettone, a brioche-type bread with raisins and candied fruit, is a product of high consumption throughout the year. Its preparation requires a large amount of flour, fat, and sugar, so its excessive consumption contributes to obesity problems and cardiovascular and metabolic diseases. Objective. To determine the nutritional contribution and evaluate the level of acceptance of panettone enriched with almonds, raisins, and dehydrated blueberries, as a healthy alternative, without modifying the characteristic organoleptic attributes recognized by its consumers. Materials and methods. In the physicochemical laboratory of the Universidad de Barranca (Lima, Peru), in December 2019, three types of panettone were formulated replacing the traditional filling with almonds, blond raisins, and dehydrated blueberries for a final composition of 40, 45, and 50 % w/w. They were subjected to sensory evaluation by ranking preference tests to qualify the attributes (color, smell, taste, and texture) and acceptance test with hedonic scale, to qualify the acceptance of the final product. The most acceptable product underwent physicochemical analysis to determine the nutritional contribution of the proposal. Results. The formulation with the highest acceptance was 45 % filler, even though the differences between treatments were not significant (p>0.05) The macronutrient content was similar to what is offered in the market (p>0.05). In relation to micronutrients, a contribution of 8 g of unsaturated fatty acids, 0.36, 5.8, 4.9, 33.3, 9.3, and 109 mg of vitamins B2, B3, E, iron, zinc, and calcium respectively, was observed per 100g g portion. Conclusion. Almonds, blond raisins, and dried cranberries improved the nutritional density of panettone, without significantly affecting the organoleptic characteristics of the product.

Vitamin E profile in rice (Oryza sativa L.) seeds grown and commercialized in Costa Rica

2022-09-27T09:03:12-06:00

Introduction. Rice (Oryza sativa L.) is one of the most consumed cereals worldwide, the indica and japonica subspecies are the most cultivated. The vitamin E present in rice has a high antioxidant activity that contributes to extend the longevity of its seeds. Its quantification allows to know the nutritional contribution of this vitamin. Objective. To analyze the vitamin E profile in seeds of indica (registered commercial, aromatic, promising in development) and japonica subspecies of rice (O. sativa L.), consumed in Costa Rica. Materials and methods. Twenty-seven materials grown in the Chorotega and Brunca regions of Costa Rica, harvested in 2020 were analyzed. Vitamin E was quantified by ultra-high performance liquid chromatography coupled to triple quadrupole mass detection with chemical ionization source at atmospheric pressure at the Centro para Investigaciones en Granos y Semillas (CIGRAS), Universidad de Costa Rica, in 2021. Results. In the vitamin E profile, a characteristic clustering was obtained for the japonica samples, which was opposite to that presented by the indica samples. The majority compounds were γ-tocotrienol, α-tocopherol, and γ-tocopherol, the range of total vitamin E concentration was 5.50 to 33.20 μg g^-1, where the japonica subspecies reported the lowest amount (6.30 – 8.80 μg g-1), while the Nayuribe sample, belonging to the registered commercial indica subspecies, obtained the highest concentration (33.20 ± 7.40 μg g^-1). Conclusion. Although the analyzed subvarieties are phylogenetically from the same species, the significant differences found in the nutritional intake of vitamin E may be due to intrinsic characteristics of each subspecies. The significantly high vitamin E content in the Nayuribe sample showed that it is possible to find stocks for a high vitamin E content among the varieties analyzed.

Effect of temperature and storage time on hen egg quality

2022-10-04T14:46:55-06:00

Introduction. The hen egg is a food of high nutritional value, with protein of high biological value and easy digestion, due to that it is indispensable to know what affects its quality when storing it. Objective. To evaluate the effect of temperature and days of storage on egg quality. Materials and methods. The trial took place between December 2019 and January 2020, in Palmares, Alajuela, Costa Rica. In two different moments, egg samples were taken from Hy Line Brown hens: 1000 eggs at the start of production (21 weeks of age) and 1000 eggs at peak of production (28 weeks of age). The eggs were stored at controlled (7-10 °C) and room ((18-26 °C) temperatures for up to 21 days. The following egg physical quality parameters were assessed: egg weight, eggshell thickness and resistance, Haugh units, and yolk color at 1, 4, 7, 14, and 21 days of storage, as well as a qualitative evaluation according to USDA standards (2000). Results. Egg weight was significantly lower at room temperatures and longer days of storage at peak production. Eggshell thickness and resistance presented a positive relationship with each other. Haugh units presented a significant decrease as storage days go by, with a higher negative slope for the eggs at room temperature. The storage temperature and days of storage degraded the perception and qualitative classification of eggs by the consumers, in higher proportion for the eggs at room temperature. Conclusion. Storage at room temperature and between 14 to 21 days were factors that affected the egg quality and the possible consumer’s perception towards this product.

Factors conditioning the adoption rate of technified irrigation systems in Mexico

2022-10-04T14:41:50-06:00

Introduction. To know the factors that determine the rate of adoption of technician irrigation systems is important because of the water savings that could be obtained by increasing the number of units that use more efficient systems. Objective. To determine the factors that affect the rate of adoption of technician irrigation systems in Mexico. Materials and methods. A logit model was estimated where the dependent variable was the logit of the ratio of probabilities of using technician irrigation systems against other irrigation systems. The independent variables were: electricity price, water value, rainfall, temperature, number of over-exploited aquifers, farm size, utilization rate of production units that use sanitary measures, and educational level of agricultural producers. The estimate was made with data from Mexico’s 32 federative entities for 2019. Results. The results indicated that, if the electricity price and the water value increase by 10 %, the rate or probability of using modernized irrigation systems increases from 24.51 to 25.42 and 26.17 %, respectively. A 10 % decrease in rainfall would increase the probability of using modernized irrigation systems from 24.51 to 25.41 %, while with a 5 % increase in temperature, this probability would increase from 24.51 to 29.40 %. Conclusion. These results demonstrated the importance of economic and climatic conditions as factors that affect the use of technician irrigation systems, therefore, in saving water.

New thilinear hybrid of hard yellow corn for the Peruvian tropic

2022-08-03T11:27:30-06:00

Introduction. Hard yellow corn (Zea mays L.) is the main source for food processing; therefore, it is necessary to generate hybrids with yields higher than 2.8 t ha^-1 and climatic adaptability. Objective. To evaluate and compare the agronomic behavior of five experimental trilinear hybrids of hard yellow corn maize and the Marginal 28T variety in eight tropical Peruvian locations. Materials and methods. The experiment took place in two phases: from March 2018 to March 2019 in four validation plots in San Martin, and from March to December 2019 in four adaptabilities plots in San Martín, Pucallpa, Loreto, and Amazonas. The evaluated variables were: plant and ear height, size and weight of ear, roots lodging, rust resistance, and yield (t ha^-1). A randomized complete block design was applied, with a combined analysis of yield genotype x environment interaction with the additive main effects and multiplicative interaction models. Results. The hybrid HTE6 had the highest ear diameter (4.66 cm), ear weight (190, 76 g), number of rows per ear (14.26), grains per row (37.45), total grain weight (156.21 g), and grain yield (7.21 t ha^-1). HTE6 showed superior adaptability in Iquitos (9.2 t ha^-1) and San Martín (8.1 t ha^-1). In the genotype-environmental interaction, it reached 7.18 t ha^-1, with the highest stability in the eight localities. Conclusion. Among the five trilinear hybrids and the Marginal 28T variety, the HTE6 had the best agronomic performance and the highest yield in the eight evaluated locations. Thus, it is considered the more suitable trilinear hybrid for the tropical conditions of Peru.

Distribution of Diaphorina citri Kuwayama (Hemiptera: Liviidae) in citrus production areas of Panama

2022-10-04T14:38:22-06:00

Introduction. The asian psyllid (Diaphorina citri Kuwayama) is the main vector of the bacterium Candidatus Liberibacter asiaticus that causes Huanglongbing (HLB) disease in citrus in Panama. Objective. To determine the geographic distribution and host plants of the asian psyllid within the citrus growing areas in Panama. Materials and methods. The study was carried out from June to October 2021 through systematic sampling within 46 localities associated with commercial citrus and home gardens in seven provinces of Panama. In each plant, two new shoots of 10 cm long were bagged with a magic-seal plastic bag to capture the specimens and introduce them into 2 mm plastic vials with 95 % alcohol for later identification. The study variable included the count of the total number of specimens, and the data was analyzed as a percentage. Results. Of the total of 73 collected samples, the presence of the Asian psyllid was confirmed in 21.92 % (16 samples). Its presence was positive in the provinces of Chiriquí, Coclé, Herrera, Panama, and West Panama, at altitudes of 17 to 1080 m.a.s.l. There was no presence of the psyllid in the provinces of Los Santos and Veraguas. Of the 16 samples that were positive, 50 % belonged to the myrtle plant, followed by orange (18.75 %), and creole lemon (12.50 %). Conclusion. The distribution of the asian psyllid vector of HLB in commercial citrus and home gardens in the main citrus growing areas in Panama was presented at different heights above sea level, mainly associated with the presence of the host plants such as myrtle, orange, and creole lemon.

Germination and growth of Sterculia colombiana in Arosemena Tola, Napo, Ecuador

2022-08-17T15:15:08-06:00

Introduction. The Amazon region has a great plant diversity, but studies on their propagation and growth have been carried out in few species. Objective. To evaluate the in situ and ex situ germination of Sterculia colombiana and its growth characteristics after planting in ground covers of primary forest and intervened areas. Materials and methods. The study was carried out in Napo, Ecuador, in the period 2019-2020. The germination of S. colombiana was characterized in the variables: days and percentage to emergence, plant height, stem diameter and number of leaves, under greenhouse conditions and planted at the collection site. The plants obtained in the germination test were transplanted to a ground cover of primary forest (in situ) and an intervened area with replacement vegetation (ex situ). Linear, quadratic, cubic, exponential, and logarithmic growth models for stem height and diameter were evaluated. The air and soil temperature and the physical-chemical characteristics of the soil were recorded. An analysis of variance was performed to determine differences in growth and survival between the plantation sites and between the plants obtained in the in situ and ex situ tests. Results. The seedlings obtained from greenhouses reported fewer days to emergence and higher values in the rest of the variables evaluated than those grown in situ. The plants developed in the different evaluated covers, without significant differences in growth at the end of the study, only a significant correlation at 5 % between stem diameter and air temperature was reported. Conclusions. Sterculia colombiana germinated in a greenhouse and developed in the transplant sites, without this influencing its growth. Temperature was the only factor that reported significant correlations with growth at the end of the evaluation period.