Heliconia SCARLET: a mexican variety for cut flower and gardening

Objective: To carry out the morphological characterization of Heliconia uxpanapensis x Heliconia latispatha var. Scarlet for varietal registration purposes. Design, Methodology and Approximation: By means of rhizomes division of 71-1 plant from a plot of H. uxpanapensis x H. latispatha segregant plants (F2), twelve plants (tillers) were generated, planted, and cultivated in open field under 30% of natural shade. Morphological characterization was methodic conducted using the Technical Guide descriptors for Heliconias designed by the National Seed Inspection and Certification Service (SNICS, 2023). Results: Morphological characters of the clones from the 71-1 segregant plant, tested with the SNICS Technical Guide descriptors, were constant so that a differentiation could be make between the Scarlet and Karely, a reference variety found in the Guide. Scarlet variety’s primary distinctive characteristics are the red color, high brilliance, and the revolute-involute margins of their bracts. Their inflorescence morphological characteristic suggest they can be cultivated for cut flower and gardening.  Study limitations and implications: In order for Scarlet variety express, their characteristics of intense color and bracts brightness, they have to be cultivated under 30% of shade. Findings and conclusions: Based on the Technical Guide descriptors for heliconias varietal description (SNICS, 2023), the Scarlet variety differentiates from the Karely (reference variety) as it presents a stability-distinction-homogeneity. For this reason, the varietal registration seems appropriate.Objective: To carry out the morphological characterization of Heliconia uxpanapensis X Heliconia latispatha var. Scarlet for varietal registration purposes.Design, Methodology and Approximation: By means of rhizomes division of 71-1 plant from a plot of H. uxpanapensis X H. latispatha segregant plants (F2), twelve plants (tillers) were generated, planted, and cultivated in open field under 30% of natural shade. Morphological characterization was methodic conducted using the Technical Guide descriptors for Heliconias designed by the National Seed Inspection and Certification Service (SNICS, 2023).Results: Morphological characters of the clones from the 71-1 segregant plant, tested with the SNICS Technical Guide descriptors, were constant so that a differentiation could be make between the Scarlet and Karely, a reference variety found in the Guide. Scarlet variety’s primary distinctive characteristics are the red color, high brilliance, and the revolute-involute margins of their bracts. Their inflorescence morphological characteristic suggest they can be cultivated for cut flower and gardening.Study limitations and implications: In order for Scarlet variety express, their characteristics of intense color and bracts brightness, they have to be cultivated under 30% of shade.Findings and conclusions: Based on the Technical Guide descriptors for heliconias varietal description (SNICS, 2023), the Scarlet variety differentiates from the Karely (reference variety) as it presents a stabilitydistinction-homogeneity. For this reason, the varietal registration seems appropriate

Diversidad morfológica y fisiológica de cepas nativas de Trichoderma spp. en suelos cacaoteros de México

Objective: To study the morphological, microscopic and physiological diversity of native species of Trichoderma genus associated with soils with cocoa cultivation in Mexico. Design / methodology / approximation: Colonies of Trichoderma spp. were isolated and characterized morphologically, microscopically and physiologically. from soil samples from six sites with different agronomic management: Organic Management, Conventional and No Management. A multivariate analysis (Analysis of main components and Analysis of hierarchical conglomerates) was carried out based on eight morphological characters of the colonies: shape, mycelium texture, obverse color, reverse color, central halo, number of concentric rings, type of sporulation and sporulation capacity; three microscopic characters: conidia shape and length / width relation of conidia and phialides. Results: 30 strains with macroscopic characteristics of the genus Trichoderma were isolated and purified. The Principal Components Analysis showed that the first three components expressed 66.27% of the total variability in the 30 strains of Trichoderma spp., observing a wide distribution of the strains from the analysis of the evaluated characters. The analysis of hierarchical clusters determined eight groups divided into subgroups from the semiparcial correlation coefficient of 0.05. Limitations of the study / implications: Trichoderma species show intraspecific variation that change with respect to the environmental conditions of the environment where they grow. Findings / conclusions: The morphological, microscopic and physiological characterization shows a high variability expressed in different characters that demonstrate the high diversity and specificity of Trichoderma spp. in soils with cocoa cultivation in Mexico.Objetivo: Estudiar la diversidad morfológica, microscópica y fisiológica de especies nativas del género Trichoderma asociadas a suelos cacaoteros de México. Diseño/metodología/aproximación: Se aislaron y caracterizaron morfológica, microscópica y fisiológicamente, colonias de Trichoderma spp. a partir de muestras de suelo de seis sitios con diferente manejo agronómico: Manejo Orgánico, Convencional y Sin Manejo. Se realizó un análisis multivariado (Análisis de componentes principales y Análisis de conglomerados jerárquicos) a partir de ocho caracteres morfológicos de las colonias: forma, textura del micelio, color anverso, color reverso, halo central, número de anillos concéntricos, tipo de esporulación y capacidad de esporulación; tres caracteres microscópicos: forma de conidios y relación largo/ancho de conidios y fiálides. Resultados: Se aislaron y purificaron 30 cepas con características macroscópicas del género Trichoderma. El Análisis de Componentes Principales mostró que los primeros tres componentes expresaron el 66.27 % de la variabilidad total en las 30 cepas de Trichoderma spp., observando una amplia distribución de las cepas a partir del análisis de los caracteres evaluados. El análisis de conglomerados jerarquicos determinó ocho grupos divididos en subgrupos a partir del coeficiente de correlación semiparcial de 0.05. Limitaciones del estudio/implicaciones: Las especies de Trichoderma muestran variación intraespecífica que cambian con respecto a las condiciones ambientales del medio donde crecen. Hallazgos/conclusiones: La caracterización morfológica, microscópica y fisiológica, muestra una alta variabilidad expresada en diferentes caracteres que demuestran la alta diversidad y especificidad de las especies de Trichoderma spp. en suelos cacaoteros de México

Morphological characterization of Elephant grass (Pennisetum purpureum Schumach) ecotypes collected in Chiapas, Mexico

Objective: To characterize the morphology of 18 ecotypes of Elephant grass (Pennisetum purpureum Schumach) in Chiapas. Design/Methodology/Approach: The morphological characterization was carried out with 34 quantitative and qualitative descriptors. A principal component analysis and a hierarchical cluster analysis were performed based on the average data. Results: In the principal component analysis, five of the principal components accounted for 70.7% of the total variability in the 18 ecotypes of Elephant grass. The variables that made the most significant contributions in each CP were: in CP1, internode diameter (p<0.01), internode length (p<0.05), color of internode without wax (p<0.01), number of innovations (p<0.01 ), prophylls (p<0.01), number of prophylls (p<0.01), external length of the sheath (p<0.01), internal length of the sheath at its opening point (p<0.01), opening of the auricle (p<0.01 ); for CP2, the number of visible internodes (p<0.05), channel width (p<0.05), size of innovations (p<0.05), adventitious root, number of internodes (p<0.01), wax under the sheath (p<0.05); and for CP3, number of visible internodes (p<0.05), color of the internode with wax (p<0.001), channel depth (p<0.001), ligule shape (p<0.05) and leaflet tip (p< 0.05). As a result of the hierarchical cluster analysis and the semipartial correlation coefficient, five morphologically distinct groups were determined. Study Limitations: A more accurate description of the morphological diversity of the grasses requires the characterization of the inflorescence and the spikelet. Findings/Conclusions: The 18 ecotypes of the Elephant grass (Pennisetum purpureum Schumach) collected and characterized were dissimilar with each other; consequently, they are considered a genetic resource with potential importance as forage on the Chiapas coast

In vitro conservation of Vanilla planifolia hybrids in minimal growth conditions

ABSTRACT Objective: In vitro conservation with minimal growth in interspecific hybrids of Vanilla planifolia. Design / Methodology / Approach: Explants from seven interspecific V. planifolia hybrids were used with parents of different origins. The treatments were different doses of mannitol and sucrose in the culture medium that varied from 0, 5, 10, 15, 20, 25 and 30 g l-1. The number of nodes, shoots and roots was recorded every 30 days for six months. Results: The results indicated that 30 g l-1 of mannitol and without sucrose in the culture medium allowed minimal growth for most hybrids. It was found that with a higher content of mannitol and less sucrose, the length, number of between nodes, shoots and roots of the explants were shorter, results that were different between treatments (P?0.05). Limitations of the study / implications: There is a differential behavior between the biological material and the culture media used, especially when it comes to hybrids due to the new genetic combinations that are generated, so for their conservation the components of the culture medium must be adjusted. Findings/conclusions: It is concluded that the mannitol at 30 g l-1 and without sucrose in the in vitro culture medium of vanilla hybrids is able to reduce its growth significantly during 180 days.Key words: Ex situ conservation, in vitro culture, Vanilla planifolia, mannitol.Objective: To maintain minimal growth in in vitro Vanilla planifolia hybrids. Design/Methodology/Approach: Explants of seven interspecific hybrids of V. planifolia with different origin parents were used. The treatments consisted of different doses of mannitol and sucrose in the culture medium which varied from 0, 5, 10, 15, 20, 25 and 30 g L-1.The number of nodes, shoots and roots was recorded every 30 d for six months. Results: 30 g L-1 mannitol and no sucrose in the culture medium allowed minimal growth in most of the hybrids. The higher the mannitol and lower the sucrose content, the length, number of between nodes, shoots and roots of the explants was lower (P?0.05). Limitations of the study/implications: There is a differential behavior between the biological material and the used culture medium, particularly in hybrids, due to their new genetic combinations. Therefore, for their conservation, the culture medium components must be adjusted. Conclusions: 30 g L-1 mannitol without sucrose in in vitro culture medium significantly reduces growth during 180 d in vanilla hybrids

In vitro production of gases with mixtures of Hyparrhenia rufa (Nees) and Leucaena leucocephala (Lam) de Wit

Objective. To evaluate in vitro the production of total gases and CH4 in different mixtures of Hyparrhenia ruffa (Hr) and Leucaena leucocephala (Ll). Design / methodology / approach: In hermetic biodigesters with 200 mL of culture medium, 20 g of the following treatments were incubated in triplicate: T1: 100% Hr, T2: 80% Hr + 20% Ll, T3: 60% Hr + 40 % Ll, T4: 40% Hr + 60% Ll; They were inoculated with 20 mL of fresh ruminal fluid and incubated at 38 ± 0.5 ° C for 24, 48, 72 and 96 hours (h). The production of total gases and methane (CH4) was measured; the data were analyzed in a completely randomized design. Results: When adding 20%, 40% and 60% of Ll in mixture with Hr, the neutral detergent fiber, acid detergent fiber, production of total gases and CH4 decreased; while the crude protein content increased. Study limitations / implications: In vivo studies are required / by including amounts greater than 20% of Ll, the efficiency of energy use can be improved. Findings / conclusions: By adding more than 20% of L. leucocephala in a mixture with H. ruffa, the production of total gases and CH4 decreases. Keywords: methane, ruminants, tropical grasses, forage shrubsObjective: To evaluate total in vitro gas and methane (CH 4 ) production in different mixtures of Hyparrhenia ruffa (Hr) and Leucaena leucocephala (Ll).Design/methodology/approach: In airtight biodigesters with 200 mL of culture medium, 20 g of the following treatments were incubated by triplicate: T1: 100 % Hr, T2: 80 % Hr + 20 % Ll, T3: 60 % Hr + 40 % Ll, T4: 40 % Hr + 60 % Ll; these were inoculated with 20 mL of fresh rumen fluid and incubated at 38 ± 0.5 °C for 24, 48, 72 and 96 h. The total gas and CH 4 production were assessed; the data were analyzed in a completely randomized design.Results: The addition of 20 %, 40 % and 60 % Ll in mixture with Hr decreased theneutral detergent fiber (NDF), acid detergent fiber (ADF), total gas and CH 4 production, while the crude protein content increased. Study limitations/implications: In vivo studies are required / by including amounts higher than 20 % Ll may improve energy utilization efficiency.Findings/conclusions: Adding more than 20 % L. leucocephala in a mixture with H. ruffa decreases total gas and CH 4 production

LD50 and GR50 estimation with gamma rays (60 Co) IN Arachis pintoi Var. amarillo

Objective: To estimate the median lethal dose (LD50) and mean reductive dose (GR50) due to gamma radiation in Arachis pintoi var. Amarillo seeds. Design/methodology/approach: Ten doses were used (100, 200, 300, 400, 500, 600, 700, 800, 900 and 1000 Gy) plus a control (without radiation). The experimental design was completely random with three replications and 50 seeds per repetition. Seed germination was evaluated 29 days after sowing (das) and plant survival, plant height, root length and leaf area at 60 das. The LD50 and GR50 for survival and plants height were estimated by linear regression. Results: There was a significant reduction of seed germination and plant survival from 300 and 200 Gy doses compared to the control (61.64 and 49.15 % each); for the plants height the dose was of 100 Gy (35.22 %). There were no differences in the root length and leaf area with 100 and 200 Gy regard to the control. The LD50 was estimated at 212.54 Gy and the GR50 at 162.16 Gy. Findings/conclusions: The gamma radiation doses to induce genetic variation in A. pintoi var. Amarillo seeds were between 162 and 212 Gy.Objective: To estimate the median lethal dose (LD50) and mean reductive dose (GR50) due to gamma radiation in Arachis pintoi var. Amarillo seeds. Design/methodology/approach: Ten doses were used (100, 200, 300, 400, 500, 600, 700, 800, 900 and 1000 Gy) plus a control (without radiation). The experimental design was completely random with three replications and 50 seeds per repetition. Seed germination was evaluated 29 days after sowing (das) and plant survival, plant height, root length and leaf area at 60 das. The LD50 and GR50 for survival and plants height were estimated by linear regression. Results: There was a significant reduction of seed germination and plant survival from 300 and 200 Gy doses compared to the control (61.64 and 49.15 % each); for the plants height the dose was of 100 Gy (35.22 %). There were no differences in the root length and leaf area with 100 and 200 Gy regard to the control. The LD50 was estimated at 212.54 Gy and the GR50 at 162.16 Gy. Findings/conclusions: The gamma radiation doses to induce genetic variation in A. pintoi var. Amarillo seeds were between 162 and 212 Gy

Determination of bacteria morphotypes associated with the rhizosphere of organic coffee plantations

Objective: To determine bacterial diversity associated with the coffee rhizosphere on coffee plantations on Oaxaca, Mexico. Design/methodology/approach: Soil samples collected from organic arabic coffee plantations in the Loxicha region of Oaxaca were analyzed to isolate and characterize populations of bacteria associated with the rhizosphere of the plantations. Six sites were sampled in three altitudinal ranges; low (≥1200, ≤1400 masl), medium (≥1700, ≤1800 masl) and high (≥1900 masl); two sites per rank. The population distribution of the bacteria by altitudinal range was compared using the Tukey test. A multivariate analysis (Principal Component Analysis and Hierarchical Cluster Analysis) was performed considering four morphological characters of the colonies: Shape, Surface, Border and Color, and two microscopic characters: Type and Gram. Results: 43 bacterial colonies were isolated and purified, whose population distribution showed a significant difference (Tukey α = 0.5) with respect to the altitudinal range of collection. The Principal Component Analysis showed that the first three principal components expressed 74.19% of the total variation of the 43 bacterial colonies, indicating a wide distribution of the bacterial colonies from the evaluated characters. The Hierarchical Cluster Analysis determined eight groups divided into subgroups based on the semipartial correlation coefficient of 0.05. Limitations on study/implications: The environmental conditions where bacteria grow allow the interspecific variation of each species to change. Findings/conclusions: The morphological and microscopic characterization of the bacterial colonies shows the existence of a high variability that is expressed in characters that indicate high diversity of bacterial species in organically managed coffee soils in Oaxaca.Objective: To determine the bacterial diversity in the rhizosphere of coffee (Coffea arabica L.) in coffee plantations in Oaxaca, Mexico. Design/methodology/approach: Soil samples collected from organic arabian coffee plantations in the Loxicha region of Oaxaca were analyzed to isolate and characterize bacterial populations associated with the rhizosphere of those plantations. Samples were collected from six sites in three altitude ranges (two sampling sites per each range): low (≥1,200, ≤1,400 masl), medium (≥1,700, ≤1,800 masl), and high (≥1,900 masl). Tukey’s test was used to compare the bacteria population distribution per altitude range. A multivariate analysis (Principal Component Analysis and Hierarchical Cluster Analysis) was performed considering four morphological —shape, surface, border, and color— and two microscopic —type and Gram— characteristics of the colonies.   Results: Forty-three bacterial colonies were isolated and purified; their population distribution showed a significant difference (Tukey α = 0.5) with respect to the altitude range in which they were collected. The Principal Components Analysis showed that the first three principal components accounted for 74.19% of the total variation of the 43 bacterial colonies, indicating that the evaluated characteristics were widely distributed. The Hierarchical Cluster Analysis determined eight groups and divided them into subgroups, based on the semi partial correlation coefficient (0.05). Study limitations/implications: The environmental conditions where bacteria grow allow changes in the interspecific variation of each species. Findings/conclusions: The morphological and microscopic characterization of the bacterial colonies shows a high variability that is expressed in characteristics, indicating a high diversity of bacterial species in organically-managed coffee soils in Oaxac

Caracterización de la diversidad nativa del zacate banderita [Bouteloua curtipendula (Michx.) Torr.], mediante su nivel de ploidía

The objectives of this study were to determine the number of chromosomes and DNA content, to identify sexual diploids and apomictic polyploids and to define the relationship between ploidy level and diverse revealing attributes of sideoats grama's productive potential. One hundred and eighty eight ecotypes of sideoats grama from 13 States of Mexico were evaluated. In order to estimate nuclear DNA content, a flow cytometer was used. Chromosome counts were carried out in root tips. The relationships between altitude, mean temperature, mean rainfall, DNA content, chromosome numbers as well as productive potential, were evaluated also. Recorded diversity ranged from 2.04 to 4.31 pg DNA/2C for DNA content, reflecting significant variation among ecotypes. Chromosome numbers ranged from 19 to 107. The first three components explained 82.7 % of the observed total variation. The most important variables for CP1 were DNA content and chromosome number, for CP2 altitude and mean temperature, and for CP3, forage yield and rainfall. Five groups were defined, based on the correlation coefficient. Variance analysis spotted significant differences (PLos objetivos fueron determinar el níºmero de cromosomas y contenido de ADN, identificar individuos diploides sexuales y poliploides apomí­cticos y definir la relación entre el nivel de ploidí­a y diversos atributos informativos del potencial productivo del pasto Banderita. Se evaluaron 188 ecotipos de pasto Banderita, procedentes de 13 Estados de la Repíºblica. Para estimar el contenido de ADN nuclear, se utilizó un citómetro de flujo. Los conteos cromosómicos se realizaron en ápices radicales. Se estimó la relación entre altitud, temperatura media, precipitación media, contenido de ADN, níºmero cromosómico y potencial productivo. La diversidad mostró un rango entre 2.04 a 4.31 pg ADN/2C para contenido de ADN, que refleja variación significativa entre ecotipos. El níºmero cromosómico mostró una variación de 19 hasta 107 cromosomas. Con los tres primeros componentes, se explicó el 82.7 % de la variación total observada. Las variables de mayor importancia en el CP1 fueron el contenido de ADN y el níºmero de cromosomas, en el CP2 altitud y temperatura y en el CP3 rendimiento de forraje y precipitación. Se determinaron cinco grupos basados en el coeficiente de correlación. El análisis de varianza detectó diferencias significativas en todas las variables (

Respuesta a altos niveles de estrés hídrico en maíz

Respuesta a altos niveles de estrés hídrico en maíz. El objetivo de este trabajo fue comparar la respuesta a la sequía, en términos de crecimiento vegetativo, desarrollo reproductivo y la acumulación de materia seca, de cuatro variedades de maíz sometidas a diferentes niveles de estrés hídrico, en el Colegio de Postgraduados, México durante el año 2003. Las variedades fueron: Zacatecas 58 original (Zo), Cafi me original (Co), Zacatecas 58 SM19 (Z19) y Cafi me SM16 (C16). Los niveles de sequía se aplicaron cuando el suelo llegó al punto de marchitez permanente, siendo éstos: 4, 10 y 20 días de sequía, seguidos de la aplicación inmediata de un riego de recuperación y riegos continuos hasta la cosecha. El crecimiento se detuvo por efecto de la sequía en las cuatro variedades, pero una vez que se aplicó el riego de recuperación, éste ocurrió de manera progresiva, de tal forma que las plantas sometidas a sequía igualaron y en algunos casos llegaron a superar a las de riego como ocurrió en Z19. El número de días a floración y asincronía fue mayor en Z19 y C16 que Zo y Co; en el índice de cosecha, las variedades originales disminuyeron menos que las mejoradas; mientras que, la biomasa fue menos afectada en las variedades mejoradas que en las originales conforme se prolongó el periodo de sequía. Por lo anterior, se concluyó que las variedades mejoradas han desarrollado un mecanismo de resistencia a sequía llamado latencia; mediante el cual, las plantas detienen su crecimiento en condiciones extremas de sequía, pero en el momento en que nuevamente hay humedad en el suelo, reinician su desarrollo hasta completarlo