Genome Wide Association and Forward Genetic Studies to Identify Genes Involved in Salt Tolerance

Salinity tolerance varies considerably between natural accessions of rice. In this project, the main aims were to identify well-known genes and novel determinant candidate genes for salinity tolerance using genome wide association study (GWAS) and forward genetic screening. To assess salinity tolerance in rice and Arabidopsis, relative growth rate of plants and cations in roots and shoots were analysed. This research has found that relative growth rate, root K+, and shoot Na+ traits are parameters for salinity tolerance in both species. Moreover, the growth parameter is correlated with the root K+ and shoot Na+. Regarding the identification of determinant genes for saline conditions, the GWAS approach has revealed 120 association signals and several of them were not revealed before using genomic mapping. The association signals contained ~1500 novel candidate genes across the rice genome and 32 well-known published candidate genes that play roles in saline conditions. One of the relevant outcomes was that the genomic region of the well-known qSaltol QTL correlated with a SNP position identified by this approach. The qSaltol has already been introgressed into elite rice cultivars and assessed for its effectiveness in saline field conditions. Concerning forward genetic screening, this approach has identified two candidate genes that have molecular functions which correlate with the candidate genes identified by GWAS. These findings may contribute to our understanding of the complex and dynamic mechanisms of plants and the roles of genes to achieve salinity tolerance in plants

Incremento de la patogenicidad de hongos en arroz bajo condiciones de desbalance nutricional

This article discusses the potential plant pathogenic fungi that affect rice grown in imbalance nutritional conditions. Rice, Oryza sativa, is the main staple food across countries of the world. The genus Rhizoctonia, Pyricularia, Alternaria, Fusarium y Curvularia have been shown as the potential pathogenic fungi which cause significant damage to shoot, stems, panicle base and rice grains. The incidence and severity of these pathogens are main affected by temperatures between 25 and 37°C, relative humidity (70-76%), soil moisture, wind, and nutritional imbalance. The genus Rhizoctonia causes brown elliptical spots, rotting of stems and panicles, which reduces yields by 19%. On the other hand, fungi within the genera Alternaria, Fusarium, Curvularia and Pyricularia cause brown spots and decrease germination, yield, specific grain weight (g L-1). Although there is research on fungi affecting rice cultivation, the association between nutritional imbalance and pathogen incidence has yet to be evaluated in germplasm of more than 100 rice cultivars under well-fed and nutritional imbalance conditions.El presente artículo discute los hongos fitopatógenos potenciales que afectan al cultivo de arroz en condiciones de desbalance nutricional. A nivel mundial el arroz es considerado como el tercer cultivo alimentario de mayor importancia. Sin embargo, es afectado por diversos hongos fitopatógenos que ocasionan daños en hojas, tallos, panículas y granos del cultivo. La incidencia de estos hongos se debe a factores como la temperatura (25-37 ºC), humedad relativa (70-76%), humedad en el suelo, el viento y desbalance nutricional. El género Rhizoctonia causa manchas con forma elíptica de coloración marrón, pudrición de tallos y panículas, lo que reduce el 19% del rendimiento. Por otra parte, los hongos que se encuentran dentro de los géneros Alternaria, Fusarium, Curvularia y Pyricularia provocan manchas de color café y disminuyen la germinación, rendimiento, peso específico del grano (g L-1). Aunque existen investigaciones acerca de los hongos que afectan al cultivo del arroz, la asociación entre el desbalance nutricional y la incidencia de patógenos aún está por evaluarse en germoplasmas superiores a 100 variedades de arroz en condiciones óptimas y de desbalance nutricional

Agroindustrial traits of sugarcane varieties

El propósito de este estudio fue evaluar los rasgos agroindustriales de ocho variedades de caña de azúcar en ciclo planta. La siembra se llevó a cabo en marzo de 2022, siguiendo las indicaciones del paquete tecnológico del INIFAP Las Huastecas. La preparación del suelo incluyó técnicas de subsuelo y rastra cruzada. Durante el ciclo de cultivo, se aplicaron riegos y fertilizantes conteniendo nitrógeno (N), fósforo (P) y potasio (K+) en las diferentes fases del cultivo. Las ocho variedades, ICPMex 92-1420, LTMex 94-2, Mex 91-662, Mex 94-8, Mex 95-59, Mex 96-35, Mex 97-20 y MotzMex 01-403, fueron sembradas manualmente a una cantidad de 12 t ha-1. Los análisis revelaron diferencias significativas entre las variedades en términos de longitud/diámetro de tallos, densidad poblacional y rendimiento. Se observaron correlaciones positivas entre la densidad poblacional/longitud de los tallos y el rendimiento, lo que subraya la importancia de establecer adecuadamente la población de cultivo. Además, se encontró una asociación positiva entre los valores de °Brix, el contenido de sacarosa y la pureza de jugos, lo que destaca el potencial de las mediciones de °Brix como indicadores confiables del contenido de sacarosa en campo. Estos hallazgos resaltan la relevancia de prácticas de manejo específicas para optimizar el rendimiento y la calidad de la caña de azúcar en el contexto agroindustrial.The study aimed to evaluate the agro-industrial traits across eight sugarcane varieties in the plant stage. Sowing took place in March 2022, following the guidelines of the technological package provided by INIFAP Las Huastecas. Soil tillage consisted of subsoiling and cross-harrowing approaches. Whereas irrigation and fertilization containing nitrogen (N), phosphorus (P), and potassium (K+) concern, NPK were applied at different plant stages. The eight varieties, ICPMex 92-1420, LTMex 94-2, Mex 91-662, Mex 94-8, Mex 95-59, Mex 96-35, Mex 97-20, and MotzMex 01-403, were manually sowed at a rate of 12 t ha-1. The analyses revealed significant differences among the varieties in terms of stem length/diameter, tiller population, and cane yield. Positive correlations were observed between tiller population, stem length and cane yield, emphasizing the importance of establishing the crop population adequately. Furthermore, a positive association was found between °Brix values, sucrose content, and juice purity, highlighting the potential of °Brix measurements as reliable traits of sucrose content in the field. These findings underscore the relevance of specific management practices to optimize the yield and quality of sugarcane in the agro-industrial context

Effect of coumaphos on Rhipicephalus microplus and entomopatho-genic nematodes in cattle production units

Objective: to determine the effect of coumaphos on Rhipicephalus microplus and entomopathogenic nematodes in bovine production units. Design/methodology/approach: Two experiments were carried out: First) tick samples were collected and evaluated, using the Adult Immersion Test (10 ticks per humid chamber), the treatments were applied: 1) Control; 2) Coumaphos 0.1 %; 3) Coumaphos 0.2 %; 4) Coumaphos 0.4 %. An ANOVA was carried out with a completely randomized design (mortality dependent variable and treatment independent variable with four levels) and a multiple comparison of means (Tukey's test). Second experiment) 10 samples of livestock soil where coumaphos is used, which correspond to the Mariano Matamoros ejido, Tamaulipas, and 10 non-livestock soil from the Las Huastecas Experimental Field, were analyzed to determine the presence of entomopathogenic nematodes (EPN). a cross-frequency table between the sampled soils and the Chi-square test. Results: Experiment 1) In counting the tick mortality percentages on the second day after application in group 1) control was 37.5 %, 2) 72.5 %, 3) 80 %, 4) 92.5 %, on day 7 and day 8 there was no difference with 90 % and 100 % mortality. Experiment 2) The soils positive to EPN were 35 % Non-livestock and 25 % Livestock. Limitations on study/implications: it is important to make producers aware of the correct use of chemical products. Findings/conclusions: R. Microplus was susceptible to coumaphos in cattle production units. A greater presence of EPN was found in non-livestock soils, which may be related to the use of chemical products to control parasites

Climate Resilient Crops for Improving Global Food Security and Safety

Food security and the protection of the environment are urgent issues for global society, particularly with the uncertainties of climate change. Changing climate is predicted to have a wide range of negative impacts on plant physiology metabolism, soil fertility and carbon sequestration, microbial activity and diversity that will limit plant growth and productivity, and ultimately food production. Ensuring global food security and food safety will require an intensive research effort across the food chain, starting with crop production and the nutritional quality of the food products. Much uncertainty remains concerning the resilience of plants, soils, and associated microbes to climate change. Intensive efforts are currently underway to improve crop yields with lower input requirements and enhance the sustainability of yield through improved biotic and abiotic stress tolerance traits. In addition, significant efforts are focused on gaining a better understanding of the root/soil interface and associated microbiomes, as well as enhancing soil properties