Agronomía Mesoamericana

Strategies in developing tropical maize hybrids.

S. K. Vasal — 1994-01-01

The strategies in a hybrid development program should be so oriented to achieve short, medium and long term objectives. The germplasm source utilized is quite important and should possess desirable agronomic traits with good plant and ear height characteristics along with good stalk quality to allow development of good progenitors. To achieve these objectives, it is imperative to introduce new strategies and modifications in the conventional systems to obtain higher efficiency. In this presentation various aspects are discussed relating to germplasm source oriented towards hybrids, integration and introduction of new schemes of population improvement parallel to hybrid development, production of vigorous and productive lines using diversified and efficient strategies, precise characterization of lines in inbred-line evaluation trials, combining ability in crosses with testers, identification of new hybrids during various stages of hybrid development, prediction of new hybrids with less number of single crosses, use of inbred lines in forming new populations as well as heterotic groups and synthetics. Options for developing single cross hybrids to add efficiency in the future are discussed.

Some considerations for the organic production of vegetables.

Floribeth Mora — 1994-01-01

This article is based on a Bibliographical Compilation where the ecosystemic problems, generated by the scientific and technological advances in modern agriculture, are analyzed. The basic principles ruling the organic, bilological, alternative or ecological agriculture are defined, emphasizing the importance of maintaining and improving the soil as the basic component of organic production, adducing that a well nourished plant is most resistant to any plague. Diseases, insects, weeds and nematodes are also mentioned, giving emphasis to practices of integrated plague management.

The phytogenetic resources: an option for the agricultural development in the American Tropics.

Jorge A. Morera — 1994-01-01

The Central American agriculture shows a low productivity in most of the cultivated crops, apparently due to a lack of improved varieties and a reduced used of cultural practices. The Central American region has climatic, topographic, edaphic and social characteristics that could allow a more integral development and exploitation of the autochthonous phytogenetic resources. Nonetheless, in spite of the significance that it has to the farmer and the industry, there is little research and information on the use and of cultural practices of some potential species of American origin. A better knowledge of the genetic diversity, seasonal production, quality, supply and demand of the products, will allow for the preparation of a list of the phytogenetic potential which is still preserved. The most important incentive of any crop is its economic profitability. On this way, the economic factor promotes the basis for developing an increased production, improve quality and open new alternatives to the farmer and the industry. If a new crop is not profitable, it is rejected inmediately; but on the other hand, if a crop is highly profitable, it is almost imposible to restrain its diffusion. The recognition and conscience drawn by the reasonable use of the "genetic resources" on the national, regional and world level, as an essential base for a dynamic and rational agriculture, by far justifies the programs of the countries in the American Tropics to join their efforts in the preservation and promotion of the genetic diversity.

Aerobiology: a new research area.

Jesús Loera — 1994-01-01

A workshop to address the science of aerobiology was held at Michigan State University‘s Kellog Biological Station on October 10-13, 1992. The purpose of the workshop was to bring together scientistis and to our-reach specialists from diverse disciplines to advance the understanding of aerobiology and improve the capability to predict the atmospheric movement of biota. Biota important to agriculture, forestry, human health and the envirommental move in predictable atmospheric transport events. The workshop participants discussed the principles of long-distance atmospheric transport of biota, formulated strategies to share diagnostic technologies and information systems, and concluded that science is positioned to make major advances in forecasting the movement of arthropods, plant viruses, fungi, and bacteria; birds and human allergens. A North American alliance for aerobiology research is being accelerate research advances in the important area of science. Approximately 70 nationally and internationally recognized scientists from agriculture, medicine, engineering, physics, eviromental science, and systems science participated in the workshop. The workshop generated (1) a set of generic foci and scientific hypotheses that will serve as guidelines to conceptualize and direct research in aerobiology, (2) recommendations for networking biological, atmospheric, and other environmental monitoring networks for in forecasting aerobiological transport events, (3) recommendations for utilizing existing electronic networks to link scientistis with agencies and institutions with and tools, (4) recommendations for developing an information database on an electronic comunications network to facilitate access to aerobioogical information, and (5) the establishment of an organizational, structure for the Alliance for Aerobiological Research (AFAR)with a governing board to serve the membership.

Biotechnology and the agricultural field.

Susana Azpíroz — 1994-01-01

This article summarizes how the modern biotechnology techniques can be used as a tool to make the traditional animal and plant breeding methodologies more efficient. The advantages and disadvantages of using these techniques were analyzed at each stage of the selection process of the breeding program. We compared the ease of handling and time saving obtained when the biotechnology component is integrated in the process used by the breeder. The new techniques analyzed were: a- Tissue and organ culture; b- Genetic transformation; c- Molecular genetic markers. Likewise, the current interest of multinational corporations on the potential of the agriculture modified by the biotechnology and the further concentration of knowledge and intellectual rights was analyzed. The importance for the Latin American countries to rule as a group and to share a common criteria in order to legislate in favor of the intellectual rights and biosafty was also emphasized. This legislation would allow a harmonic development of biotechnology among our countries.

Effect of hot red pepper supplementation and different storage time on hens egg quality

Muhammad Fathin Hanif — 2024-09-23

Introduction. Eggs are a food source of protein that easily deteriorates during storage. Supplementation of hot red chilli pepper powder rich in bioactive compounds in diets for laying hens can improve egg quality and prevent egg deterioration during storage. Objective. To determine the effect of hot red pepper powder supplementation and different storage times on the physical egg quality of laying hens. Materials and methods. This study was conducted from January to March 2024 at the Research Barn of PT. Agromix Lestari Group, Kulon Progo, Yogyakarta, Indonesia. Eighty 56-week-old Novogen laying hens (1681 ± 64 g) were assigned into four dietary treatments (4 replications, 5 hens per replication): basal diet as control (P0); basal diet + 0.25 % hot red pepper powder (P1); basal diet + 0.5 % hot red pepper powder (P2); and basal diet + 0.75 % hot red pepperpowder (P3). At the end of week 6, one egg per replicate group was collected and analyzed for physical quality in three storage treatments: fresh condition (S0), one week storage (S1), and two weeks storage (S3). Egg quality data were analyzed with a factorial experimental design (4 x 3) using SPSS 26 software. Results. Supplementation of 0.5 % hot red pepper powder significantly increased egg weight. Hot red pepper addition and treatment duration significantly affected egg yolk colour. The hot red pepper treatment group showed significantly lower pH of albumen and yolk. Conclusions. The supplementation of hot red pepper powder in laying hens diets has been shown to improve the egg yolk color. The inclusion of 0.5 % in the ration was able to keep the pH of yolk and albumen low.

Biological potential of Beauveria spp. for the control of Anthonomus eugenii in sweet pepper

Stephanie Quirós-Campos — 2024-09-23

Introduction. Anthonomus eugenii causes considerable economic losses in sweet pepper (Capsicum annuum). Chemical control is ineffective; therefore, it is essential to explore other management alternatives. Objective. Determine the potential of Beauveria spp. strains for the biological control of Anthonomus eugenii in sweet pepper under greenhouse conditions. Materials and methods. The research was conducted between May and august 2023 at the Fabio Baudrit Moreno Experimental Station in Alajuela, Costa Rica, in a 96 m² multispan greenhouse. The evaluated treatments were INTA H-140, INTA H-149, INTA H-168, and INTA H-181, along with an absolute control, using a completely randomized design (CRD) with three replications. The number of live adults and infested peppers were quantified weekly. Pearson correlation analysis and repeated measures ANOVA were performed for the evaluated variables. Results. There was interaction between treatments and evaluation date for the number of adults (p < 0,05). INTA H-168 strain significantly reduced the Anthonomus eugenii population in 60 ddt and 64 ddt evaluations, with differences of 22,96 and 47,15 adults, respectively. For the variable of the number of infested peppers, there was only an individual effect by ddt (p < 0,05). Additionally, a positive correlation was found between the average number of infested peppers and the number of live adults for the 64 ddt and 73 ddt (p < 0,05). Conclusion. The significant reduction in live adults in the first two evaluations of INTA H-168 strain and its parasitism evidence biological potential for the control of Anthonomus eugenii.

Valorization of Algerian food by-products in animal feed

Samira Lagha-Benamrouche — 2024-09-23

Introduction. The valorization of food by-products in animal feed has emerged as a pivotal strategy. This innovative approach not only addresses the challenge of food waste management but also contributes to the optimization of resources in animal nutrition. Objective. To characterize food waste (carob molasses residue, carob seeds, bitter orange peels, and brown chicken eggshells) with a view to its use as a value-added feed supplement for animals based on its biologically active compounds. Materials and methods. In this study, several food by-products were utilized, including carob molasses residue, orange peels, and eggshells. The biological material was collected in Boumerdes, Algeria, during 2021, according to the ripening period of the plant material (August for carob and December for oranges). For the characterization of the different components of the biological material, phytochemical tests based on coloring reactions, HPLC, atomic absorption spectrophotometry, and solubility in solvents were employed. Results. The by-products were found to be low in fat and protein and moderately high in sugar. Orange peel constitutes a reservoir of vitamin C, carotenoids, and phenolic compounds. The mineralogical study showed a predominance of calcium, magnesium, and phosphorus in the eggshells. The comparison of by-products shows that carob seeds are the least rich in crude fiber and therefore supply more available carbohydrates, providing more assimilable energy compared to other by-products. Conclusion. These food byproducts provide bioactive compounds, including vitamin C, carotenoids, phenolic compounds, as well as some minerals, and offer more available energy. The combination of these by-products constitutes a value-added food supplement for livestock feed.

Effect of Bacillus megaterium on strawberry crop

Ramiro Daniel Acurio-Vásconez — 2024-09-23

Introduction. In Ecuador, strawberry cultivation holds significant economic and social importance, having witnessed substantial growth in recent years. However, this sector faces challenges from various pests and diseases. Objective. To evaluate the effect of Bacillus megaterium on strawberry crop variables related to plant health and agronomic yield. Materials and methods. Field trial was conducted on the Albion variety of strawberries, four months after the first harvest, in Pichincha province, Ecuador. Using IB6 and AB4 strains of Bacillus megaterium at concentrations of 1x109 y 5 x108 cfu/L. These were compared with a chemical control using captan (3 g/L) and chlorothalonil (2 mL/L) as fungicides, and abamectin (0.75 mL/L) and lambdacyhalothrin (0.3 mL/L) as insecticides in rotation. A split-plot design with evaluations conducted at two intervals between April and June 2023. Variables measured included Botrytis cinerea incidence and severity index, fresh weight, yield, diameters, and Brix degrees of fruits. Results. There was no interaction between the factor showed no statistical difference for variables of health and agronomic interest, the incidence of B. cinereal in the biological treatments was the lowest with 13 % on average, the control of mites was 72.71 % higher with strain IB6 high concentration this same treatment, showed significant increases in the fresh weight of fruits (13.2 %), diameters (14 %), and soluble solids concentration (23 %) higher than the control. Conclusion. The use of Bacillus megaterium reduced the incidence of Botrytis cinereal, effective control against mites and thrips, improved fresh weight, diameters and Brix degrees of fruits.

Obtaining wild sunflower (Helianthus annuus L.) plants for bioassays with herbicides

Ma. Eugenia Cisneros-López — 2024-09-23

Introduction. The wild sunflower or polocote (Helianthus annuus L.) is the main annual weed in the cultivation of sorghum and corn in northern Tamaulipas, Mexico. To date, there is little information about this species to carry out bioassays with herbicides. Objetive. Establish a methodology for obtaining polocote seedlings for bioassays with herbicides from seed to multiplication in the nursery. Materials and methods. The polocote seed was collected in January 2023, within the INIFAP Experimental Field, in Río Bravo, Tamaulipas. Afterwards, the initial germination test was carried out on filter paper and viability with Tetrazolium, latency was confirmed due to low germination (12 %) and high viability (86 %). Twelve treatments were used to break it using ethanol (70 %) and water (75, 25), as a control only water, at 5 ^oC and 20 ºC on paper, filter, cotton and Peat moss in Petri dishes for seven days and then at (± 25 ºC). With the previous results, the nursery phase was established with four schemes with pre-germinated seed transplantation and two with direct sowing. Results. The best treatment to break dormancy was immersion in water at 5 ºC for seven days on cotton with 73 %. The best methods to obtain plants were trays with seedlings and transplanting into black open-air pots with 75 and 50% survival, respectively. The shade inhibited the growth of the plants. Direct sowing, with or without seed prehydration, was unfavorable for germination and emergence. Conclusion. Obtaining wild sunflower seedlings was higher when the seed was subjected to water pre-treatment and subsequent transplanting into trays or open-air bags.

Prevalence of ahpnd in shrimp farms of the Nicoya Gulf and Central Pacific, Costa Rica

Nelson Peña-Navarro — 2024-09-23

Introduction. The Acute hepatopancreas necrosis disease (AHPND) is caused by bacteria Vibrio parahaemolyticus containing a plasmid encoding the toxin genes pirA and pirB. The disease is characterized by massive sloughing of epithelial cells in hepatopáncreas, also showing atrophy and discoloration of that organ. Diseased shrimp display anorexia with empty gut, weakness, body discoloration and high mortalities. Objective. To determine the prevalence of Vibrio parahaemolyticus causing AHPND in farms that grow shrimp in the Pacific zone of Costa Rica. Material and methods. During the years 2019 and 2020, water and shrimp (P. vannamei) samples were obtained from 32 farms located in the western coast of the Gulf of Nicoya (Northwest of Costa Rica) and the Central Pacific coast (Puntarenas- Parrita) The samples were analyzed by the endpoint Polymerase Chain Reaction (PCR) using different protocols and primers to detect the toxins pirA and pirB. Further, a linear correlation between the presence of AHPND and water quality was done using the R statistical program. Results. The presence of Vibrio parahaemolyticus causing AHPND occurred in 93.75 % (30/32) of sampled ponds in both farming areas. Conclusion. This work confirms the presence and wide distribution of AHPND in water and shrimp from thirty shrimp farms in the Costa Rican Pacific.

Agronomy undergraduate students’ perceptions of ethics and animal welfare in relation to animal-based entertainment

Anthony Valverde — 2024-09-23

Introduction. Undergraduate Agronomy students recognize the importance of animal production to satisfy the nutritional requirements of society; however, there is an epistemological gap regarding the use of animals in recreational activities. Objective. To explore the ethical and bioethical perceptions of students regarding animal welfare and the use of animals for entertainment purposes. Materials and methods. A survey was conducted among the population of active students at the ITCR Agronomy Engineering career during 2023, to evaluate the perceptions about animal welfare and the ethical use of animals in recreational activities. The application of the instrument allowed to describe the characteristics of the observed phenomenon in relation to the students’ perceptions of animal welfare. The data were analyzed using a t test to examine whether the means of two independent groups were significantly different from each other. Results. The level of concern for animal welfare in the student population was high (70.8%, n = 102; p<0.001). Furthermore, this concern is 4 times greater if the respondent was a woman compared to men (odds ratio 4.91, p<0.001). The students indicate that there is a gradation of animal suffering (56.7% n = 81, p<0.001) and the majority consider it to be unethical to perform entertainment activities using animals (73.6% n = 106, p<0.05). Conclusion. The students expressed support for animal welfare and recognized the ethical responsibility of humans towards them to avoid their unnecessary suffering. Their is suggested to incorporate multidisciplinary approaches in the curricula of Agronomy-adjacent degrees regarding human-animal relationship studies.

Citrus peel flour as an ingredient for the meat industry

Jorge Velasquez-Rivera — 2024-09-23

Introduction. Citrus fruits (specially orange (Citrus sinensis) and mandarin (Citrus reticulata)) are among the most widely products consumed in the world, but their industrial processing generates a significant amount of subproducts. These subproducts represent a valuable source of bioactive substances. Among the most abundant subproducts are citrus peels, which contain several composed with antioxidant , antimicrobial activity and fiber. Objective. This study will help to describe the potential benefits of the use of citrus peels as a source of bioactive compounds, and explore their applications as an ingredient for the development of healthier meat and its products. Development. In this compilation, we analyze the main characteristics of citrus peels, emphasizing their chemical composition, physical properties, and value as a source of a bioactive compound as well as what the scientific literature points about their use as an ingredient in meat products. In this article there are discussions about the changes introduced in the chemical, sensory, textural, color and durability characteristics of the meat products. These alterations are attributed to the presence of bioactive compounds, including antioxidants, antimicrobials, flavor components, polyphenols, flavonoids, essential oils, pigments, carbohydrates, and dietary fibers. The impact of these compounds varies on their origin, concentration, and way of addition. Conclusion. The industrialization of citrus produce a large amount of subproducts, wealthy in bioactive compounds with antioxidant, and antimicrobial properties which constitute a viable alternative to develop healthier and more sustainable meat products, which would also have suitable sensory properties and a larger and useful life, but in each case it has to be considered the proper characteristics of the subproduct and the food matrix where it would be used.

Application of zinc nitrate plus chitosan favors carbon assimilation and bean (Phaseolus vulgaris L.) yield

Bryan S. Valencia-Vázquez — 2024-06-13

Introduction. A novel alternative to increase productivity and nutrient utilization is the use of biostimulants such as chitosan, which is a product derived from the exoskeleton of crustaceans and has properties that promote growth and nutrition in crops. Objective. To evaluate the application of zinc nitrate (NZN) plus chitosan on biomass, yield, photosynthetic activity and photosynthetic pigments in green bean plants (Phaseolus vulgaris L.) for consumption of the fresh pod. Materials and methods. The experiment was conducted in a shade house located at the Centro de Investigación en Alimentación y Desarrollo (CIAD), located in Delicias, Chihuahua, Mexico; during the months of August to October 2021. A completely randomized design with eight treatments and four replications was used, where zinc nitrate was applied via foliar at doses of 0, 25, 50 and 100 ppm with and without chitosan at a dose of 50 ppm. Biomass accumulation, yield, in vivo nitrate reductase enzyme activity, photosynthetic activity using Licor 6400 equipment, photosynthetic pigment content, and foliar and fruit zinc concentration were evaluated. Results. The results obtained indicate increases for the biomass variable when applying doses of 50 ppm NZN and 25 and 50 ppm NZN plus chitosan of 37.76 %, 42.39 % and 40.61 % respectively in relation to the control without application, while for yield an increase of 45.22 % was obtained when NZN plus chitosan was applied at a dose of 25 ppm. The application of chitosan individually did not show statistical differences. Conclusions. The application of zinc nitrate plus chitosan increased total biomass production, yield and Zn content in fruit. It also favored photosynthetic activity and parameters related to photosynthetic pigments.

Jasmonate and salicylic sprays improve cherry tomato fruit productivity and quality in unheated greenhouses

Bassim Almass Essa — 2024-09-23

Introduction. Arable regions often have insufficient soil nutrients, which means that fertilizers must be used. However, using fertilizers excessively can harm the environment, human health, and food safety. Natural growth regulators derived from plants are environmentally friendly and reasonably priced. Salicylic acid (SA) and methyl jasmonate (MeJA) phytohormones are crucial for enhancing plant biomass, quality, productivity, and resistance to environmental stresses. Objective. To evaluate the foliar effect of MeJA and SA on fruit quality and production of cvs. colorful tomato under greenhouse conditions. Materials and methods. The trial was carried out in the University of Diyala, Iraq, from 1 December, 2022 to 5 June 2023. Foliar of 0, 200 mg/L SA and or 200 mg/L MeJA was evaluated to determine effects on fruit quality and production of colorful cherry tomato cultivars indeterminate: LA4013, LA353, LA2921, LA3899 and IQ2, with a randomized complete block design with each treatment having three replicates. Results. The cv. IQ2 had the heaviest fruit (82.13 g), highest yield (4.56 kg/plant), total yield (4.56 t/house) and highest treatable acidity (0.62 %). The cv. LA4013 had a higher fruit number (612.88 fruit/plant) and the highest total soluble solids (2.933 %). Foliar of SA at 200 mg/L had the highest chlorophyll index (36.68 SPAD) highest fruits per plant (373.73), highest yield (3.15 kg/plant) and total yield (3.93 t/house). Conclusion. When considering all variables together, the best genotypes were IQ2 and LA4013, which were found to be superior to the other genotypes in quality and yield trials. The 200 mg/L foliar SA improved the yield and quality of cherry tomatoes under greenhouse conditions.

Effect of oil palm compost and sandy soil on the growth of cacao (Theobroma cacao L.) seedlings

Oscar A. Tuesta — 2024-06-13

Introduction. Low-fertility soils and high logistics costs for seedling production characterize the Peruvian Amazon. Objective. To evaluate the effect of a combination of sandy soil and oil palm compost on substrate, growth, and nutrition of cocoa seedlings under greenhouse conditions. Materials and methods. The experiment was conducted for 90 days in Yurimaguas-Loreto using a completely randomized design in a 5x5 matrix, with five doses of Oil Palm Compost and Sandy Soil to determine the best combination for cocoa growth and nutrition. Height (cm), diameter (mm), leaf area (cm2), dry weight of stem and root were measured; soil chemical analysis and plant analysis (macro and micronutrients) were also conducted. Results. Sandy soil showed no significant effect on cocoa seedlings, while treatments with oil palm compost promoted shoot and root biomass. Additionally, this compost favored conditions for seedling growth by promoting higher organic matter, available phosphorus, exchangeable calcium, potassium, and higher cation exchange capacity. Regarding cocoa nutrition, it promoted greater absorption of macro and micronutrients in cocoa seedlings. Conclusions. These results indicate that the best treatment was the one composed entirely of oil palm compost, as it promotes growth and nutrition by improving substrate conditions.

Labeling, responsible and sustainable food consumption: Consumer perception in Costa Rica

David Gómez Castillo — 2024-09-23

Introduction. Over the last few decades, there has been growing interest on the part of consumers in sustainable agri-food products. As a result, voluntary standards have emerged as a tool to promote sustainability in production and consumption in agri-food value chains. Objective. To evaluate the profile of consumers and the degree of knowledge of sustainability seals for agricultural products in Costa Rican markets. Materials and methods. During October and November 2021, a nationwide virtual survey was conducted through the Qualtrics platform, from which 397 valid responses were collected. The sustainability seals considered were certifications of organic production, fair trade, denomination of origin, country-essential Costa Rica brand and carbon neutral. The Poisson regression model (PRM) was used to study the behavior of the variables, using Stata software version 16.0. Results. The Essential Costa Rica seal is the most recognized. People residing in the Greater Metropolitan Area (GAM) are more familiar with various seals. The income variable turned out to be a significant factor; those with higher incomes tend to identify and value sustainability seals more. The level of knowledge and consumption of certified products increases when the consumer has some link to the agricultural sector. Conclusions. People’s interest in certified products is not reflected in their purchasing behavior, due in part to the price of the products, lack of trust or excessive information on labels. The findings of the study allow companies to define their marketing strategies according to the characteristics of the consumers of these differentiated products.

Soil macrofauna in agroecosystems of Coffea arabica L., in Tepec-Xomolth, Nicaragua

Juan Carlos Morán Centeno — 2024-06-13

Introduction. The coffee tree is an item of great importance worldwide, having a direct impact on the economies of countries. In Nicaragua, it represents 25 % of exports. The coffee plant production agroecosystem is made up of components that are found above and below the soil surface. Objective. To estimate the populations of soil macrofauna in productive coffee plantation agroecosystems and their relationship with soil fertility and management practices. Materials and methods. The research was conducted from May to August 2023 in fourteen coffee plantation production systems in the Tepec-Xomolth La Patasta nature reserve. Soil monoliths measuring 25 x 25 x 20 cm were extracted, and three transects were established in each system, separated by 50 m. Specimens collected were identified at the family level. The data were analyzed using descriptive statistics, generalized linear models, hypothesis tests, and diversity indices. Results. Significant statistical differences (p<0.5) were found for rural communities and practices. Soil fertility varied according to the altitude of the farms, with abundant macrofauna in the Nueva Esperanza community (20,672 individuals) and shade management (23,632 individuals). Fifteen orders and 38 families were identified, with the insect class and the trophic group of predators predominating. Diversity was high and stable, a result of the management practices employed by the producers. Conclusions. Taxonomic richness and abundance of macrofauna were similar in the evaluated systems, specifically in the orders Haplotaxida, Coleoptera, Hymenoptera, and Isopoda, where detritivores, omnivores and predators stand out. The study revealed that crop management directly affects soil diversity, indicating that the soils are minimally disturbed and there is ecological balance.

Impact evaluation combining ability of tomato hybrids and lines for production and fruit quality traits

Bassim Almass Essa — 2024-06-13

Introduction. The selection of pure lines followed by crosses to create superior hybrids is one of the oldest strategies in crop breeding. Combining ability studies provide reliable information for selection of parents for hybrid combination by revealing the nature and magnitude of gene actions involved in expression of quantitative traits. Objective. To estimate the General and Specific Combining Ability (GCA and SCA) values for yield in cherry tomatoes and select F1 hybrids combining high yield and fruit quality traits. Materials and methods. The half-diallel design, following method 2 of Griffing was used to define the best breeding method. Five lines were crossed to produce 10 hybrid combinations using a half diallel design involving the parents. Crosses and evaluations were conducted in a greenhouse in the Experimental Station at the University of Diyala, Baqubah, Iraq, in the winter of 2022-2023. Results. Based on GCA effects, lines 'LA353', 'LA3899' and 'IQ2' could be potential donor parents in breeding. Based on average performance, heterosis manifested and SCA effects, crosses IQ2×LA4013, LA3899×LA353 and IQ2×LA3899 were best in respect to yield and fruit quality. Conclusion. The general and specific combining ability values for the majority of the traits supported the material's great variety. The magnitude of heterosis was improved compared to parental lines. The high-yielding parent lines 'LA3899' and 'IQ2' could be used for breeding cherry tomatoes under greenhouse conditions.

Gene expression in Longissimus dorsi and liver in two stages of growth in pigs

Clemente Lemus-Flores — 2024-06-13

Introduction. It is said that genetic expression varies in relation to the physiological stage of the pig and the nutritional source, it is different in muscle and liver. Objective. Identify the genes that present differential genetic expression, through transcriptome analysis in Longissimus dorsi and liver, during growth and final fattening, differentiating them into two stages of pig fattening, growth group (55 ± 1.05 kg) and final group (101 ± 7.8kg). Materials and methods. 12 total samples were considered, three from Longissimus dorsi muscle and three from liver per stage for RNA extraction and sequencing. With the DESeq2 method, the gene expression of the Log2FC was obtained differentially for the Growth Group vs final fattening of Longissimus dorsi and Liver and the biological function of the DEG genes was identified. Results. The largest number of genes with DEG were identified in the liver and on chromosome 6 in Longissimus dorsi and liver. In Longissimus dorsi from the growth group with high expression, the genes FUT1, SESN2 and FGF21 associated with growth and with low expression, NR4A3, PDK4, PER1 and PTPRO involved in immune system processes and circadian rhythm were identified. In the liver of the Growth Group, with high expression, the IHH and MYL7 genes were identified, and with low expression, the genes MFSD2A, LIPG, THBS1, TGFB2, LTF and APOA4 were identified as those most involved in biological processes. Conclusions. In Longissimus dorsi from the growth group the genes were related to growth and in final fattening with immunity, growth and meat quality. In the liver of the growth group the genes were related to growth and in the final fattening group with immunity, growth, nutrient and lipid metabolism, lipoproteins and detoxification.

Influence of mycorrhizal fungi on growth and cadmium adsorption in sunflower (Helianthus annuus L.)

Omar Enrique Cartaya-Rubio — 2024-06-13

Introduction. Heavy metals can accumulate in the soil and affect plant growth. The symbiosis established between plants and arbuscular mycorrhiza-forming fungi (AMF) improves the tolerance of plants to heavy metal toxicity, being considered an alternative for the management of plants grown in soils affected by heavy metals. Objective.To evaluate the effect of different arbuscular mycorrhizal-forming fungi on cadmium absorption and vegetative growth of sunflower (Helianthus annuus L.). Materials and methods. The research was carried out in the years 2021-2023, at the National Institute of Agricultural Sciences (INCA), San José de las Lajas, Mayabeque, Cuba. Sunflower seeds were inoculated with the strains INCAM-4 (Glomus cubense) and INCAM-11 (Rhizoglomus intraradices), at a rate of 45 spores/g, in a soil with high levels of Cd. After 60 days, the plant height, dry weight, chlorophyll content, percentage of mycorrhization and viability of fungal structures and the effect of AMF on cadmium partitioning in sunflower plants. Results. Sunflower plants showed a beneficial response to inoculation with strains of arbuscular mycorrhizal fungi, with a differentiated behavior between the strains and with the greatest effects obtained in growth, biomass production and in the phytoextraction process with the INCAM- strain. 11, by increasing the concentration of metal in the plants to 8.01 mg kg-1 and an infection percentage of 60% and visual density 5.01. Conclusions. Arbuscular mycorrhizae increased cadmium absorption and vegetative growth of sunflower.

Growth and nutrients uptake of dragon fruit (Hylocereus costaricensis and H. monocanthus) cultivated in Costa Rica

Gabriel Garbanzo-León — 2024-04-11

Introduction. The cultivation of dragon fruit (Hylocereus costaricensis and H. monocanthus) is increasing in Costa Rica, but technical information for its management, such as nutritional requirements, fertilization timing, and growth behavior, is lacking. Objective. To quantify and model the growth and nutrient uptake of dragon fruit (H. costaricensis and H. monocanthus) under dry tropics conditions in Costa Rica. Materials and methods. The research was conducted from 2017 to 2020 in Guanacaste, Costa Rica. Plants were sampled at 76, 165, 308, 450, 607, 903, 1249, and 1706 days after planting (DAP) and 205 fruits were analyzed. Dry matter was quantified, and the uptake of N, P, Ca, Mg, K, S, Fe, Cu, Zn, Mn, and B was calculated. Two logistic models were fitted to determine nutrient uptake, and linear regressions were calibrated for fresh fruit. Results. For a planting density of 3000 plants/ha, the nutritional requirements per hectare were: 137 kg N, 32 kg P, 327 kg K, 63 kg Mg, 32 kg S, 1,60 kg Zn, and 0,21 kg B. The best-fitting logistic model (RMSE = 0.09) accurately estimated the uptake of N, P, Ca, S, Zn, and B. The linear regression model demonstrated high predictive capacity (R2 > 0.85) for the nutrient requirements of N, P, K, Mg, and S in the fruit. Conclusion. Logistic models provided high precision in deterministically modeling nutrient uptake in dragon fruit plants. The study affectively quantified and modeled the nutritional behavior of the plants under Costa Rica’s dry tropical conditions, providing essential information for optimizing fertilization programs for the crop.

Molecular identification of microorganisms in agriculture, ornamental and forest crops in Costa Rica, 2009-2018. Part 2

Mónica Blanco-Meneses — 2024-06-13

Introduction. The identification and detection of microorganisms using molecular techniques has become a very helpful tool for the disease diagnosis, and other microorganisms present in crops. Pathogenic, non-pathogenic organisms, biological controllers, and other microorganisms used as competitors, antagonists, or mutualists can be isolated from agriculture, ornamental, and forest crops. Objective. Taxonomically identify, using molecular techniques, pathogenic and non-pathogenic bacteria and yeast isolated in agriculture, ornamental, and forest crops in Costa Rica and preserve the material in a DNA bank. Materials and methods. Between 2009 and 2018, the Molecular Techniques Laboratory, at the Plant Protection Research Center, Universidad de Costa Rica, received a total of 181 isolates of bacteria and yeast for detection by end-time and real-time PCR; and identification through sequencing of specific regions. Results. Of the total samples, 94.2 % were analyzed by sequencing and 5.8 % by PCR. Using PCR, bacteria species were identified in rice, such as Burkholderia spp., Acidovorax avenae, and Pseudomonas fuscovaginae. Through sequencing of the partial 16S region, 172 samples of bacterial species were identified, and five samples of yeast species with the ITS region of the 18S ribosomal RNA. Microorganisms isolated from eighteen species of agricultural, ornamental, and forest plants were identified. The genera most identified were Pseudomonas, Bacillus, and Enterobacter, and in the case of yeast Candida, Pichia, and Wickerthamomyces. Conclusion. This research allowed us to taxonomically identify bacteria and yeast from crops in Costa Rica. In addition, a consultation input is developed, and the possibility of future use of the microorganisms that are preserved at the DNA bank.

Soil microorganisms and their relationship with coffee beverage quality: A review

José Andrés Rojas-Chacón — 2024-04-11

Introduction. Coffee (Coffea spp.) is the second most traded product globally and is cultivated in over eighty countries. Its cultivation is complex because it belongs to an ecosystem where abiotic and biotic factors interact under various agronomic management conditions. To understand the development of the coffee plant and its influence on the sensory quality of the final product, it is necessary to explore the intricate interactions between the coffee plant and the native microorganisms within the crop environment. Objective. To describe the role of the coffee soil microbiota, specially bacteria and fungi, and how they may contribute to the final quality of the beverage. Development. Soil is one of the most diverse and least studied ecosystems, where crucial ecological functions for plant growth and development take place. Identifying soil microbial components and their interactions with other organisms is important from an agronomic perspective. The soil microbiota can enhance plant physiology; thus, this review aims to connect how the sensory attributes of coffee beverage can be positively influenced by soil microbiota. Articles from ScienceDirect, Scopus, Web of Science, and Google Scholar from 2011 to 2023 were reviewed. The data show the diversity of plant growth-promoting rhizobacteria (PGPR), nitrogen-fixing bacteria (NFB), and arbuscular mycorrhizal fungi (AMF) associated with coffee cultivation. Additionally, microbial compounds play an important role in the formation of sensory attributes and are related to the coffee cup quality. Conclusion. The microbial diversity of soil and on the fruit can synthesize or degrade compounds that affect the sensory profile of the coffee beverage, which could have implications for sustainability and quality.

Infrared thermography as a tool for measuring water stress index in avocado cultivars (Persea americana M.)

Lia Ramos-Fernández — 2024-09-23

Introduction. Avocado cultivation is susceptible to water stress during the flowering stage and initial fruit growth. This stress can cause premature fruit drop and accentuate the alternation in production. Objective. To determine the water stress index of the crop (CWSI) in three avocado cultivars (Hass, Fuerte, and Zutano) under different irrigation conditions, using infrared thermography. Materials and methods. The study was carried out in the autumn season of 2023, at the Canaán Agricultural Experimental Station, Ayacucho, Peru. A total of 170 four-year-old avocado trees in the reproductive phase were selected. Five evaluations were carried out under different irrigation conditions, where information was collected after 14 and 7 days without irrigation (WI-14d and WI-7d) and 12, 2, and 1 hour after irrigation (AI-12h, AI-2h, and AI-1h, respectively). Leaf temperature (Th), stomatal conductance (gs), soil moisture (θ), and CWSI were recorded. Results. The three cultivars evaluated in this study showed significant differences in Th according to irrigation management. These variations, influenced by environmental temperature and humidity, established stress thresholds that defined the CWSI in a range from 0.34 to 0.96. When relating the CWSI with gs and θ, an R of 0.51 and 0.61 was obtained respectively. The Zutano cultivar showed the highest CWSI value in prolonged periods of irrigation restriction, but had a low capacity to reduce these values after rehydration, unlike the other cultivars. Conclusions. Infrared thermography is a crucial tool for assessing the water status and responses of avocado cultivars to different irrigation and environmental conditions, with Th and CWSI as indicators that respond to environmental conditions.

Communication in symbiotic associations Mechanisms between arbuscular mycorrhizal fungi, plants and soil organisms

William Watson-Guido — 2024-09-23

Introduction. Arbuscular mycorrhizal fungi (AMF), form close symbiotic associations with 90 % of plant species. They engage in a molecular dialogue using infochemical and nutrient molecules to regulate this mutualistic association. Objective. To gather information on the molecular mechanisms involved in the communication between AMF, their host plant and other soil organisms. Development. The symbiosis between mycorrhizal fungi and plants depends on specific signaling molecules that allow recognition, signaling and communication, in addition to physical contact between both organisms. The mechanisms of molecular communication and biological interactions between AMF with plants at different times of interaction are described, placing emphasis on the description of currently known regulatory genes, proteins, and target molecules. In addition, molecular interactions with other soil organisms are described. Conclusions. The mechanisms of molecular communication between mycorrhizal fungi and plants are complex and still present gaps in knowledge that must be filled to fully understand the ecological importance of AMF and the interactions with other edaphic organisms and thus achieve their use.