Genetic Uniformity of the MSXJ papaya hybrid (Carica papaya L.) during Micropropagation

Objective. To analyze the genetic uniformity of the MSXJ papaya hybrid vitroplants, obtained via direct organogenesis. Design/methodology/approach. The MSXJ papaya hybrid presents quality characteristics for national and export markets. The in vitro plant tissue culture represents a tool for its multiplication and conservation, but somaclonal variation can decrease its genetic and agronomic uniformity. In order to analyze the genetic uniformity of this hybrid vitroplants, 10 ISSR primers were used in micropropagated vitroplants during nine subcultures. DNA extraction was carried out with the CTAB method. The data analysis was performed with the PopGene v 1.3.1 program. Results. Eighty five loci of 200 to 2000 bp were generated, with 37 polymorphic loci. In the cluster analysis, three groups were observed that separated subculture one, subcultures two through eight, and subculture nine; the Gst value of 0.87 indicated genetic uniformity up to subculture eight. Limitations/implications. Papaya is one of the most important tropical fruits worldwide; however it is necessary to have healthy and genetically uniform plants that guarantee their quality. In vitro propagation allows to produce healthy and uniform plants, but it is necessary to study their genetic uniformity during their micropropagation. Findings/conclusions. The in vitro multiplication of the MSXJ papaya hybrid allowed to regenerate vigorous plants in 30 days. Molecular profiles indicated that up to subculture eight plantlets were genetically uniform, so it is recommended not to carry out more than eight subcultures during micropropagation.Objective: To analyze the genetic uniformity of MSXJ hybrid papaya in vitro plants, obtained by direct organogenesis.Design/Methodology/Approach: The MSXJ papaya hybrid demonstrates quality characteristics for the national and exports market. In vitro culture of plant tissues represents a useful tool for their multiplication and conservation, but somaclonal variation can diminish their genetic and agronomic uniformity. In order to analyze the genetic uniformity of in vitro plants of this hybrid, ten ISSR primers were used for in vitro plants micropropagated during nine subcultures. DNA was extracted using the CTAB method. Data were analyzed using the program PopGene v 1.3.1.Results: Eighty-five loci of 200 to up to 2000 pb were generated, with 37 polymorphic loci. In the cluster analysis, three groups were observed which separate subculture one, subcultures two to eight, and subculture nine; the Gst value of 0.87 indicated genetic uniformity as far as subculture eight.Study Limitations/Implications: Papaya is one of the most important tropical fruits worldwide; however, these plants need to be healthy and genetically uniform to guarantee commercial success. In vitro propagation allows obtaining healthy and uniform plants, but it is necessary to study genetic uniformity during their micropropagation.Findings/Conclusions: The in vitro multiplication of the MSXJ papaya hybrid permitted the regeneration of vigorous plants in 30 d. Molecular profiles indicate that as far as subculture eight, there is genetic uniformity. As such, no more thaneight subcultures are recommended during micropropagation

Sex Identification of in vitro Plants of Carica papaya L. MSXJ Hybrid through Molecular Markers

Objective: To identify the sex in vitro plants of the MSXJ hybrid papaya (Carica papaya L.) obtained via somatic organogenesis, using molecular markers SCAR type. Design/methodology/approach: Plants of the MSXJ hybrid papaya with eight months of age and during the fruiting stage were collected at the municipality of Cotaxtla, Veracruz. They were superficially disinfected, with plenty of running water, detergent for 30 minutes, 70% alcohol was added for one minute, 30% commercial chlorine for another 30 minutes and rinsed with sterile distilled water. Subsequently the meristems were grown under a MS medium, and after 30 days a subculture was performed. The extraction of DNA was performed using the Doyle and Doyle method. The PCR was done by the Deputy et al. method, and initiators T1, T12 and W11 were used. Results: Initiator T1 was positive control. Initiators T12 and W11 allowed the amplification of fragments identifying hermaphrodite, female and male plants, while the T12 and W11 initiators were specific to hermaphrodite plants. Study limitations/implications: Papaya producers know the genus of plants three months after planting. Sexuality in papaya plants cannot be differentiated until the flowering step. Findings/conclusions: the implementation of molecular markers could facilitate large-scale plant selection, reducing costs, maintenance time and the elimination of plants with unwanted sex.Objective: To identify the sex of in vitro plants of papaya (Carica papaya L.) MSXJhybrid obtained via somatic organogenesis, through SCAR type molecular markers. Design/Methodology/Approach: Eight-month old MSXJ papaya hybrid plants in thefructification stage were collected in Cotaxtla, Veracruz, Mexico. They weresuperficially disinfected with abundant running water, detergent during 30 min, andthen alcohol at 70% was added for one minute, commercial chlorine at 30% for 30min, and they were rinsed with sterile distilled water; then the meristems werecultivated in MS medium and after 30 d a subculture was made. The DNA extractionwas made with the CTAB method, and the DNA PCR was done with the Deputy et al.(2002) method, and the primers T1, T12 and W11 were used.Results: The T1 primer was the positive control and the T12 and W11 primersallowed the amplification of fragments that identify hermaphrodite, feminine and maleplants, while the T12 and W11 primers were specific for hermaphrodite plants.Study Limitations/Implications: It is required to standardize the method for it to beinexpensive.Findings/Conclusions: The sexuality of papaya plants can be differentiated until thestage of flowering, which is why the implementation of molecular markers wouldfacilitate plant selection if it is implemented at a large scale. Costs, maintenance timeand elimination of plants of unwanted sex are reduced this way

ECOLOGICAL NICHE OF SEMIDOMESTICATED POPULATIONS OF Capsicum pubescens RUIZ & PAV. BASED ON ACCESSIONS FROM VERACRUZ, MEXICO

Para cultivar una especie silvestre es necesario modificar el esquema genético resultante de los procesos de selección natural a uno adaptado a las condiciones manejadas por el hombre, e implica detectar áreas geográficas similares a aquellas donde se originó la especie. En este estudio se analiza un modelo de áreas geográficas potenciales para la adaptación de Capsicum pubescens Ruiz & Pav. con el objetivo de detectar las condiciones de nicho ecológico apropiado, determinar zonas potenciales en México y describir las relaciones entre el medio ambiente y las características morfológicas del fruto. Se utilizó el algoritmo reciente de máxima entropía (MaxEnt) para modelar el nicho de C. pubescens dentro de una región de importancia en el centro de Veracruz, México. Se utilizó un total de 44 sitios de presencia y cuatro variables bioclimáticas para detectar nichos adecuados para la especie; así mismo, se realizó un análisis de regresión por mínimos cuadrados parciales (PLS) combinando los sitios de presencia, variables bioclimáticas y características morfológicas del fruto. Se construyó un mapa final de idoneidad identificando las áreas adecuadas para el crecimiento de C. pubescens. Las contribuciones de las variables predictoras al modelo fueron preipitación anual (Bio12) 43.9 %, capa de potasio (K) 23 %, altitud (DEM) 22.3 % y temperatura media anual (Bio1) 10.7 %, con valor del área bajo la curva de 99.7 %. Los mínimos cuadrados parciales corroboraron la importancia de las covariables, que intervienen en la expresión de características morfológicas del fruto, ayudando a entender mejor las relaciones entre especies y el medio ambiente. Áreas aún no exploradas arrojaron probabilidades de ocurrencia mayores a 90 %, principalmente en las zonas montañosas de Chihuahua, Tamaulipas, Nuevo León y la Sierra de Santa Martha al sur del estado de Veracruz. Se identificó un grupo de accesiones sobresalientes que podrían servir como base para iniciar un programa de mejoramiento genético en esta especie

Varietal description of two genotypes of manzano chili pepper (Capsicum pubescens Ruiz & Pav.)

Objective: the objective of this research work was to obtain the varietal description of two varieties of chile manzano in Las Montañas in the center of Veracruz, México. Design/methodology/approach: the varietal characterization module was established under greenhouse conditions at the Centro de Bachillerato Tecnológico Agropecuario No. 99 in the municipality of Coscomatepec de Bravo. The recorded descriptors were in accordance with the International of Plant Genetic Resources Institute for Capsicum and the Graphic Handbook for Variety Description of manzano hot pepper. The plants were characterized from the seedling to the adult plant. The agronomic management of the crop was carried out in accordance with the manual for the production of manzano hot pepper in Las Montañas of the state of Veracruz. Results: all qualitative descriptors were constant for the two varieties MEXUVNE1-15-C2 and MEXUVCU1-16-C2 from seedling to fruiting; in contrast, there were dissimilarities in plant height, stem, leaf, flower, fruit and seed dimensions. Limitations of the study/implications: the pandemic caused by COVID-19 was the main limitation so that some descriptors were not recorded in a timely manner as indicated in the Graphic Handbook. Findings/conclusions: both varieties are very similar; however, the greatest distinction was in the quantitative type descriptors such as: plant height, fruit length, fruit diameter and number of seeds.Objective: The objective of this research study was to obtain the varietal description of two varieties of manzano chili pepper in Las Montañas region, in central Veracruz, Mexico. Design/methodology/approach: The varietal characterization module was established under greenhouse conditions. The markers recorded were in accordance with the International Plant Genetic Resources Institute for Capsicum and the Graphic Handbook for Variety Description of manzano chili pepper. The plants were characterized from seedling in greenhouse to adult plant. The agronomic management of the crop was carried out in accordance with the manual for the production of manzano chili pepper in Las Montañas, state of Veracruz. Results: All qualitative markers were constant for the two varieties, MEXUVNE1-15-C2 and MEXUVCU1-16-C2, from seedling to fruit setting. In contrast, there were dissimilarities in plant height, and stem, leaf, flower, fruit and seed dimensions. Study limitations/implications: The pandemic caused by COVID-19 was the main limitation, resulting in some markers not being recorded in a timely manner as indicated in the Graphic Handbook. Findings/conclusions: Both varieties are very similar; however, the greatest distinction was in the quantitative markers, such as: plant height, fruit length, fruit diameter and number of seeds

Fertilización complementada con sílice en la resistencia del tomate a Fusarium oxysporum Schtdl.

Tomato production stands in first place worldwide. This fruit presents benefits as an antioxidant and is widely used in the Mesoamerican cuisine. In this crop, Fusarium oxysporum causes one of the principal diseases that produce wilting and plant death. In fertilizers use, it is known that application of silica improves resistance to diseases. The objective of this work was to evaluate the effect of fertilization supplemented with silica on resistance of tomato to F. oxysporum. In Peñuela, Veracruz, Mexico, from April to July 2015, doses recommended by the manufacturer, and also one 20% lower and other 20% higher of PSD, Silifertidol Ultra y Fosfosilidol fertilizers were applied to tomato plants. The benefit of silica in plant growth was significantly associated with fertilizer sources and the applied doses. The best result was observed when doses 20% higher than the recommended, were applied, and Cid F1 variety was more susceptible to F. oxysporum. The fertilizer with the best results on the severity and incidence was PSD, and best growth was observed when silica was applied at between 33 and 40%. This investigation reached as a conclusion that the application of fertilizers supplemented with silica, resulted in an improved growth of tomato plants and an increased resistance to F. oxysporum, due to the increase in photosynthetic activity and thickness of the cuticle.A nivel mundial, el tomate ocupa el primer lugar en producción. Este fruto presenta beneficios como antioxidante y es ampliamente usado en la cocina mesoamericana. Entre las enfermedades que presenta se encuentra la causada por Fusarium oxysporum, que produce marchitez y muerte de la planta. El uso de fertilizantes complementados con sílice mejora la resistencia a patógenos. El objetivo de este trabajo fue evaluar el efecto de la fertilización complementada con sílice sobre la resistencia del tomate a F. oxysporum. En Peñuela, Veracruz, México, se aplicaron de abril a julio del 2015, tres fuentes de sílice en las dosis recomendadas por el fabricante, una 20% menor y otra 20% mayor de los fertilizantes Potencializador Solubilizador (PSD), Silifertidol Ultra y Fosfosilidol, en las variedades Cid F1 y Pony Express. El beneficio del sílice en el crecimiento de la planta estuvo asociado significativamente a las fuentes de fertilizante y las dosis aplicadas. Resultó mejor la aplicación de fertilizantes con dosis 20% mayores a las recomendadas por el fabricante. La variedad Cid F1 fue más susceptible a F. oxysporum. El fertilizante con mejores resultados sobre la severidad e incidencia fue PSD, y el mejor crecimiento se observó con contenidos de sílice de 33 y 40%. Por lo que, se concluye que fertilizantes complementados con sílice, contribuyeron al mejor crecimiento de plantas de tomate y al aumento de la resistencia a F. oxysporum, debido al aumento en la actividad fotosintética y en el grosor de la cutícula

Phenotypic Characterization of Quality Protein Maize Endosperm Modification and Amino Acid Contents in a Segregating Recombinant Inbred Population

The protein quality of maize (Zea mays L.) can be improved by replacing normal Opaque2alleles with nonfunctional recessive alleles (o2). Homozygous o2 kernels have increased levels of lysine and tryptophan. Unfortunately, the associated soft texture of the o2 kernels causes poor yield and susceptibility to diseases and insects. Breeding has resulted in the development of o2 genotypes with improved endosperm hardness; such genotypes are referred to as quality protein maize (QPM). Quality protein maize germplasm is utilized in breeding programs worldwide and has been competitive in yield trials. To understand the genetics of endosperm modification, a population of 146 recombinant inbred lines (S5 to S7) derived from a cross between the o2 inbred B73o2 and the QPM inbred CML161 was evaluated in two Texas locations from 2004 to 2006. The endosperm traits texture, opacity, and vitreousness were highly affected by inbred line genotype, were highly correlated with each other, and exhibited high broad-sense heritability. Relative content of the essential amino acids lysine, tryptophan, and methionine were also highly affected by the inbred line genotype, and exhibited high broad-sense heritability. Negative correlation was observed between endosperm texture traits and amino acid contents. Favorable responses to selection can be expected for both endosperm texture modification and relative content of the essential amino acids if they are efficiently monitored.This article is published as Gutierrez-Rojas, Andres, M. Paul Scott, Otto R. Leyva, Monica Menz, and Javier Betrán. "Phenotypic characterization of quality protein maize endosperm modification and amino acid contents in a segregating recombinant inbred population." Crop science 48, no. 5 (2008): 1714-1722, doi: 10.2135/cropsci2007.08.0429.</p