Distribución espacial de la precipitación sobre el crecimiento inicial del cedro rojo (Cedrela odorata L.)

Objective: To analyze the effect of the spatial variability of precipitation on the initialgrowth of red cedar (Cedrella odorata L.) in Soconusco, Chiapas, Mexico.Design / methodology / approach: The plantations were established in June 2010 inSuchiate, Tapachula and Tuxtla Chico, Chiapas; with a density of 1,111 trees ha -1planted and spaced 3.0 mx 3.0 m. Every six months (210-2014) tree height (h; m) anddiameter at chest height (DBH; cm) were measured).Results: The average annual height of the trees was correlated; with the accumulatedannual precipitation (Pp; mm), and a simple linear regression equation (R2= 0.94) wasdetermined, which predicts that the growth of the red cedar was 0.09 m for every 100mm of precipitation observed in the different localities. Likewise, its initial growth wasadjusted with a high level of confidence (P?0.001) to the first phase of the Richardssigmoidal model and, from its first derivative, the annual growth rates were determined:2.58 m year-1, 2.05 year -1 and 1.86 year -1 m for the towns of Tapachula, Tuxtla Chicoand Suchiate, respectively.Study limitations / implications: The first phase of the Richards model is onlyapplicable for the initial growth of red cedar and, beyond four years of age, it presentserrors. 2Conclusions: The first phase of Richards' sigmoidal model under the conditionsstudied, predicts with high confidence the initial growth of red cedar for the conditions ofSoconusco, Chiapas.Objetivo: Analizar el efecto de la variabilidad espacial de la precipitación sobre el crecimiento inicial del cedro rojo (Cedrella odorata L.) en el Soconusco; Chiapas, México.Diseño/metodología/aproximación: Las plantaciones se establecieron en junio de 2010 en Suchiate, Tapachula y Tuxtla Chico, Chiapas; con una densidad de 1,111 árboles ha -1 sembrados y espaciados 3.0 m x 3.0 m. Cada seis meses (210-2014) se midieron altura del árbol (h; m) y diámetro a la altura del pecho (DAP; cm).Resultados: Se correlacionó la altura promedio anual de los árboles; con la precipitación anual acumulada (Pp; mm), y se determinó una ecuación de regresión lineal simple (R 2 =0.94), la cual predice que, el crecimiento del cedro rojo fue de 0.09 m por cada 100 mm de precipitación observada en las diferentes localidades. Asimismo, su crecimiento inicial se ajustó con alto nivel de confianza (P?0.001) a la primera fase del modelo sigmoidal de Richards y, a partir de su primera derivada, se determinaron las tasas de crecimiento anual: 2.58 m año -1 , 2.05 m año -1 y 1.86 m año -1 para las localidades de Tapachula, Tuxtla Chico y Suchiate, respectivamente.Limitaciones del estudio/implicaciones: La primera fase del modelo Richards, sólo es aplicable para el crecimiento inicial del cedro rojo y, más allá de cuatro años de edad presenta errores.Hallazgos/conclusiones: La primera fase del modelo sigmoidal de Richards bajo lascondiciones estudiadas, predice con alto nivel de confianza el crecimiento inicial delcedro rojo para las condiciones del Soconusco, Chiapas

Karely, new variety of cut flower heliconia, suitable for the humid Mexican tropics

Objective: To describe Heliconia uxpanapensis x Heliconia latispatha Var. Karely, interspecific variety generated for cut flower based on commercial standards. Design/methodology/approach: Interspecific hand pollination was carried out between H. uxpanapensis Gutiérrez Báez x H. latispatha Benth. The female parent is endemic to Mexico, it presents compact growth due to its pachymorphic rhizome, red inflorescence, erect and bracts in distal position. H. latispatha has an expansive growth due to its leptomorphic rhizome, it has yellow with red inflorescence, erect and helical. The F1 hybrid was self-fertilized and produced viable seed. The mature zygotic embryos were germinated in vitro, the seedlings were acclimatized at six months and at ten months they were established in the field; Heliconia Var Karely was generated from this population. Results: Karely variety is F2 product of the interspecific cross between H. uxpanapensis x H. latispatha, it presents a compact growth habit, erect inflorescence, bracts in distal position of orange color with red border. The inflorescence is clean, it does not present watermarks that accumulate its bracts. Post-harvest life is greater than 15 days. Limitations on study/implications: Karely be cultivated under the agroforestry system in conditions of 20 to 30% shade for the adequate pigmentation of the bracts. In addition, it requires sandy-loam soil for proper development and growth of its inflorescence. Findings/conclusions: Karely has ideal characteristics for cut flowers and meets the characteristics established by the national and international market.Objective: To describe Heliconia uxpanapensis x Heliconia latispatha var. Karely, interspecific variety generated for cut flower based on commercial standards. Design/Methodology/Approach: Interspecific hand pollination was carried out between H. uxpanapensis Gutiérrez Báez x H. latispatha Benth. The female parent is endemic to Mexico; it presents compact growth due to its pachymorphic rhizome, red and erect inflorescence, and bracts in distal position. H. latispatha grows expansively due to its leptomorphic rhizome, its inflorescence, composed of orange bracts, is erect and helical. The F1 hybrid was self-fertilized and produced viable seed. The mature zygotic embryos were germinated in vitro, the seedlings were acclimatized at six months and at ten months they were established in the field; Heliconia var. Karely was generated from this population. Results: Karely variety is F2 product of the interspecific cross between H. uxpanapensis x H. latispatha, it presents a compact growth habit, erect inflorescence, bracts in distal position of orange color with red border. The inflorescence is clean and healthy. The postharvest half-life is 15 days Study Limitations/Implications: Karely must be cultivated under an agroforestry system in conditions of 20 to 30 % shade for the adequate pigmentation of the bracts. In addition, it requires sandy-loam soil for proper development and growth of its inflorescence. Findings/Conclusions: Karely has ideal characteristics for cut flower and meets the characteristics established by the market

Caracterización morfoagronómica de coyol (Acrocomia aculeata Jacq.) para determinar su potencial productivo de aceite para biodiesel

Objective: To characterize morphologically natural populations of Acrocomia aculeata to determine the potential production of oil for biodiesel. Design/morphology/approach: Eight natural populations of the species were selected in the states of Chiapas and Oaxaca. As descriptors 25 quantitative and qualitative characters were selected. The analysis of the main components and hierarchical conglomerates was performed with the PRINCOMP and PROC CLUSTER procedures of SAS, respectively. The dendrogram of groups of populations with morphological similarities was generated. Results: The first three main components explain 69.4% of the total morphological variation. CP1 explained 29.6% of the total variation with the characters stem diameter, mesocarp thickness, seed length, seed width, seed length-width ratio, seed thickness and seed weight. CP2 explained 26.1% of the variation, with the characters fruit width, fruit length, mesocarp color, and oil content in the mesocarp. CP3 explained 13.7% of the variation with the length of the rachis, epicarp color and endocarp color. The eight populations were integrated into five morphologically distinct groups. Limitations on the study/implications: It is necessary to expand the number of populations for greater precision on the diversity of the species in Mexico. Findings/conclusions: A wide genetic diversity of A. culeata was found. The variables that mostly explain this diversity correspond to the fruit and seed. The species represents a viable alternative for obtaining inputs for the production of biodiesel in Mexico.Objetivo: Caracterizar morfológicamente poblaciones naturales de Acrocomia aculeata para determinar su potencial para la producción de aceite para biodiesel. Diseño/metodología/aproximación: Se seleccionaron ocho poblaciones naturales de la especie en los estados de Chiapas y Oaxaca. Como descriptores se seleccionaron 25 caracteres cuantitativos y cualitativos. El análisis de componentes principales y conglomerados jerárquico se realizó con los procedimientos PRINCOMP y PROC CLUSTER de SAS, respectivamente. Se generó el dendograma de grupos de poblaciones con similitudes morfológicas. Resultados: Los tres primeros componentes principales explican el 69.4% de la variación morfológica total. El CP1 explicó el 29.6% de la variación total con los caracteres diámetro del tallo, grosor del mesocarpio, longitud de semilla, ancho de semilla, relación longitud-ancho de semilla, grosor de la semilla y peso de semilla. El CP2 explicó el 26.1% de la variación, con los caracteres ancho del fruto, largo del fruto, color del mesocarpio y contenido de aceite en el mesocarpio. El CP3 explicó el 13.7% de la variación con los caracteres longitud de raquis, color de epicarpio y color de endocarpio. Las ocho poblaciones se integraron en cinco grupos morfológicamente distintos. Limitaciones del estudio/implicaciones: Es necesario ampliar el número de poblaciones para una mayor precisión sobre la diversidad de la especie en México. Hallazgos/conclusiones: Se encontró una amplia diversidad genética en A. aculeata. Las variables que mayormente explican dicha diversidad corresponden al fruto y semilla. La especie representa una opción viable para la obtención de aceite para la producción de biodiesel en México

Unique haplotypes of cacao trees as revealed by trnH-psbA chloroplast DNA

Cacao trees have been cultivated in Mesoamerica for at least 4,000 years. In this study, we analyzed sequence variation in the chloroplast DNA trnH-psbA intergenic spacer from 28 cacao trees from different farms in the Soconusco region in southern Mexico. Genetic relationships were established by two analysis approaches based on geographic origin (five populations) and genetic origin (based on a previous study). We identified six polymorphic sites, including five insertion/deletion (indels) types and one transversion. The overall nucleotide diversity was low for both approaches (geographic = 0.0032 and genetic = 0.0038). Conversely, we obtained moderate to high haplotype diversity (0.66 and 0.80) with 10 and 12 haplotypes, respectively. The common haplotype (H1) for both networks included cacao trees from all geographic locations (geographic approach) and four genetic groups (genetic approach). This common haplotype (ancient) derived a set of intermediate haplotypes and singletons interconnected by one or two mutational steps, which suggested directional selection and event purification from the expansion of narrow populations. Cacao trees from Soconusco region were grouped into one cluster without any evidence of subclustering based on AMOVA (FST = 0) and SAMOVA (FST = 0.04393) results. One population (Mazatán) showed a high haplotype frequency; thus, this population could be considered an important reservoir of genetic material. The indels located in the trnH-psbA intergenic spacer of cacao trees could be useful as markers for the development of DNA barcoding