Distribución geográfica de los parientes silvestres del acervo genético mesoamericano del frijol lima (Phaseolus lunatus L.) en México

The Mesoamerican gene pool of wild Lima bean (Phaseolus lunatus L., Fabaceae) is an important source of genes for genetic improvement of the species. Is widely distributed from northern Mexico to northern Argentina. Reports in Mexico indicate that this gene pool is distributed from Sinaloa to Chiapas on the Pacific Coast and southern Tamaulipas to the Yucatan Peninsula on the Coast of Gulf of Mexico, as well as, in the Isthmus of Tehuantepec. However, despite the knowledge we have about the distribution of this gene pool, in Mexico there are still collecting gaps and unexplored regions. The objective of this study was to collect wild populations of Lima bean in Mexico to know its current distribution and establish management and conservation strategies. To do this, we collected within the natural distribution range of the Mesoamerican gene pool of Lima bean in Mexico, with the passport data was designed a geographical distribution map and assessed the conservation status of populations. Results indicated that wild populations of Lima bean have a wide geographical distribution localized mainly in tropical deciduous forest and semideciduous and elevations from zero to 2, 292 meters. In most wild population collected a low conservation status was observed, in consequence was proposed the development of strategies for in situ and ex situ conservation for wild populations with higher degree of erosion.El estudio de la fenología de las especies permite entender y predecir épocas de floración y fructificación útiles en el manejo de árboles tropicales caducifolios. La presente investigación se realizó en tres plantaciones de Cordia dodecandra (P1, P2 y P3) establecidas en el año 2002 en Xmatkuil, Yucatán, que se han manejado de diferente manera: poda, riego y deshierbe (P1); deshierbe (P2) y sin manejo (P3). Los objetivos de este trabajo fueron evaluar la fenología, la producción y calidad de los frutos de tres plantaciones. La fenología se determinó una vez al mes, utilizando el método de Fournier. La producción se evaluó cosechando y contabilizando la totalidad de frutos de todos los árboles de cada plantación, y la calidad del fruto, mediante el peso y medidas del largo y ancho de una muestra (n=20) de cada plantación. Además, se obtuvo el porcentaje de humedad de los mismos poniéndolos en una secadora a 60° C. Los resultados mostraron que P1 presentó hojas en porcentajes del 100% en septiembre 2011, en octubre disminuyó y el porcentaje de hojas fue de 25% y posteriormente en el periodo de noviembre 2011-agosto 2012 nuevamente hubo 100% de hojas. P2 y P3, perdieron sus hojas durante el periodo diciembre-marzo. Respecto a la floración, P1 presentó flores en porcentajes del 25% durante casi todo el año, a excepción de junio y julio, en los que no se registró la presencia de ninguna estructura floral; el pico máximo se observó en marzo. Las otras dos plantaciones sólo tuvieron floración durante la época de sequía (diciembre-mayo). En el mes de febrero, P2 presentó un pico máximo y P3 en marzo. La presencia de frutos en P1 se observó en octubre, noviembre y enero, incrementándose hasta obtener un pico máximo en mayo. En P2 la fructificación se observó de enero-junio y presentó un pico máximo en marzo, y en P3, de febrero-mayo con pico máximo en mayo. La mayor producción y calidad de frutos se registró en P1 presentando diferencias significativas

Genetic diversity of Huaya India (\u3ci\u3eMelicoccus oliviformis\u3c/i\u3e Kunth), a neglected Neotropical fruit crop

Currently, some species of Sapindaceae are important fruit crops worldwide. The Huaya India (Meliccocus oliviformis, Sapindaceae) is a neglected Neotropical fruit tree consumed locally in the Maya Lowlands of Mexico, where it exists in both wild and domesticated forms. Our objective was to evaluate the genetic diversity of the Huaya India in its possible domestication area and thus generate knowledge that serves as the basis for a commercial management. A total of 450 individuals collected from 15 natural vegetation sites and 15 Maya villages, were characterized using nine microsatellite loci and population genetics approaches were applied. STRUCTURE, Neighbor-Joining and PCoA analyses suggested the existence of three main groups: 1) one composed by 14 natural vegetation sites, 2) one integrated by 10 Maya villages plus one natural vegetation site, 3) one composed by five Maya villages. At the species level, genetic differentiation was high (FST = 0.562) and gene flow was low (Nm = 0.395); between genetic groups, differentiation was low and gene flow was high. Genetic diversity was low at the level species (HE = 0.19) and higher in the group composed for only natural vegetation sites. When we considered only two groups (natural vegetation sites vs Maya villages) to explore a possible bottleneck as a consequence of human management, the natural vegetation sites showed higher, and significant, genetic diversity (HE = 0.231) than the Maya villages (HE = 0.152). This study can serve as a basis to develop management strategies for Huaya India in the Maya Lowlands of Mexico, but without compromising its conservation

Characterization of the genetic structure and diversity of maize (Zea mays L) landrace populations from Mexico

Maize (Zea mays L) is a globally important crop. In Mexico, its center of origin and diversity, it forms part of the culture and staple diet of present-day towns. This condition has allowed the development of a large number of maize landraces. In southern Mexico, in the states of Yucatán, Quintana Roo, Campeche and Chiapas, little attention has been given to the diversity potential that landraces represent in order to make best use of them. This work therefore characterized the genetic structure and diversity of 16 maize landrace populations from the southern region of Mexico using ISSR markers. A total of 69 loci were generated with 100% polymorphism. The analysis revealed the formation of two groups with geographical and genetic origins in the Yucatán Peninsula and the state of Chiapas. Wide genetic diversity was found for the entire sample of assessed populations (He = 0.40 and I = 0.54), as well as in the groups formed (He = 0.36, I = 0.52 and He = 0.35, I = 0.50 respectively). At the population level within each group, the populations that formed the Yucatán Peninsula group had greater mean diversity values than in the Chiapas group (He = 0.33, I = 0.36 and He = 0.32, I = 0.35 respectively). Based on this information, it is recommended to develop in-situ conservation programs and to increase the existing ex-situ collections in the region that allow us to enhance the germplasm of the maize landraces of Mexico in breeding programs

Distribución geográfica de los parientes silvestres del acervo genético mesoamericano del frijol lima (Phaseolus lunatus L.) en México

Abstract: The Mesoamerican gene pool of wild lima bean (Phaseolus lunatus L., Fabaceae) is an important source of genes for genetic improvement of the species. Is widely distributed from northern Mexico to northern Argentina. Reports in Mexico indicate that this gene pool is distributed from Sinaloa to Chiapas on the Pacific Coast and southern Tamaulipas to the Yucatan Peninsula on the Coast of Gulf of Mexico, as well as, in the Isthmus of Tehuantepec. However, despite the knowledge we have about the distribution of this gene pool, in Mexico there are still collecting gaps and unexplored regions. The objective of this study was to collect wild populations of lima bean in Mexico to know its current distribution and establish management and conservation strategies. To do this, we collected within the natural distribution range of the Mesoamerican gene pool of lima bean in Mexico, with the passport data was designed a geographical distribution map and assessed the conservation status of populations. Results indicated that wild populations of lima bean have a wide geographical distribution localized mainly in tropical deciduous forest and semideciduous and elevations from zero to 2 292 meters. In most wild population collected a low conservation status was observed, in consequence was proposed the development of strategies for in situ and ex situ conservation for wild populations with higher degree of erosion.Resumen: El acervo genético mesoamericano del frijol lima silvestre (Phaseolus lunatus L., Fabaceae) representa una fuente importante de genes para el mejoramiento genético de la especie. Presenta una amplia distribución geográfica que abarca del norte de México al norte de Argentina. En México los reportes muestran que este acervo se distribuye de Sinaloa hasta la región de Chiapas, por la costa del Pacífico y del sur de Tamaulipas hasta la Península de Yucatán por la Costa del Golfo de México, así como también en la región del Istmo de Tehuantepec. Sin embargo, a pesar del conocimiento que se tiene sobre la distribución de este acervo, en México aún existen regiones con vacíos de colecta para P. lunatus. El objetivo del presente trabajo consistió en realizar colectas de poblaciones silvestres del frijol lima en México, para conocer su distribución actual y establecer estrategias de manejo y conservación. Para ello, se realizaron colectas dentro del área de distribución natural del acervo genético mesoamericano del frijol lima en México, se diseño un mapa de distribución geográfica con los datos de pasaporte y se analizó el estado de conservación de las poblaciones. Los resultados demostraron que las poblaciones silvestres del frijol lima, presentan una amplia distribución geográfica localizándose principalmente en zonas de selva tropical caducifolia y subcaducifolia con altitudes de cero a 2 292 metros. Se observó un bajo estado de conservación en la mayoría de las poblaciones silvestres colectadas, en consecuencia, se propuso el desarrollo de estrategias de conservación in situ y ex situ para las poblaciones silvestres con mayor grado de erosión

Producción y calidad de fruto de limón persa (Citrus x latifolia Tanaka ex Q. Jiménez) en la época invernal con mantenimiento de diferentes tensiones de humedad del suelo

Objective: to evaluate the effect of three soil moisture tension (SMT) on  lime yield and fruit quality in winter season. Design/methodology/approach: Effect of three  SMT (-10kPa, -35kPa and -85kPa) was studied. The variables evaluated were yield and quality attributes (size and color), taste (total soluble solids, titrated acidity and Brix/acidity ratio) and texture (fruit firmness and juice content). Results: Yield and percentage of large fruits decrease as the SMT increases. No significant statistical difference was found between SMT of -10kPa and -35kPa in color variables, juice percentage, firmness and TSS, but were statistically different from the values found at -85kPa of SMT. Limitations of study/implications: Although treatments that improve production and fruit quality were found, more studies are required to better understand the floral induction process in the winter season, as well as study the effect of SMT levels on the phenological stage of flowering. Findings/conclusions: Results show that the highest production was achieved with the SMT of -10 kPa. Fruit yield decreased as SMT increased. Color, size, firmness and juice content of the fruit improved by reducing SMT.Objetivo: Evaluar el efecto de tres tensiones de humedad del suelo (THS) sobre la producción y la calidad de frutos de limón persa en la época invernal. Diseño/Metodología/Aproximación: Se estudió el efecto de tres THS (-10kPa, -35kPa y -85kPa). Las variables evaluadas fueron el rendimiento y atributos de calidad de apariencia (tamaño y color),  sabor (sólidos solubles totales, acidez titulable y la relación Brix/acidez) y la textura (firmeza del fruto y contenido de jugo). Resultados: El rendimiento  y el porcentaje de frutos grandes disminuyen conforme aumenta la tensión de humedad en el suelo. No se encontró diferencia estadística significativa entre las THS de -10kPa y -35kPa en las variables de color, porcentaje de jugo, firmeza y SST, pero fueron estadísticamente diferentes a los valores encontrados a -85kPa de THS. Limitaciones del estudio/implicaciones: Aunque se encontraron tratamientos que mejoran la producción, se requiere de más estudios para comprender mejor el proceso de inducción floral en la época invernal, así como estudiar el efecto de niveles de THS en la etapa fenológica de floración. Hallazgos/conclusiones: Los resultados muestran que el mayor rendimiento se obtuvo con la tensión de humedad del suelo de  -10 kPa. El rendimiento de fruto disminuyó conforme se incrementó la tensión de humedad en el suelo. El color, tamaño, firmeza y el contenido de jugo del fruto mejoraron al reducir la tensión de humedad en el suelo

High Temperature and Elevated CO2 Modify Phenology and Growth in Pepper Plants

The aim of this study was to determine the effect of temperature and CO2 on seed emergence, seedling quality, and phenological stage of Capsicum chinense and Capsicum annum cultivated in four controlled growth chambers (C1: 30 °C and 400 μmol CO2 mol−1; C2: 40 °C and 1200 μmol CO2 mol−1; C3: 30 °C and 1200 μmol CO2 mol−1; C4: 40 °C and 400 μmol CO2 mol−1). Neither temperature nor elevated CO2 influenced seed emergence, although differences were observed in seedling mortality, with high temperature affecting seedling survival in both species; the mortality rate at 40 °C was 20 and 53% in C. annuum and 45 and 58% in C. chinense at 400 and 1200 μmol CO2 mol−1, respectively. Differences were also observed in growth parameters, where positive effects were observed on leaf area, which reached 45.9 cm2 in C. annuum and 23.9 cm2 in C. chinense with elevated CO2 at 30 °C, but negative effects were observed with high temperature. CO2 enrichment increased flower and fruit production per plant. However, high temperature delayed flower phenology, increased flower abortion and inhibited fruit set. Elevated CO2 counteracted the detrimental effects of high temperature on growth parameters and flower number, but this was not sufficient to prevent flower abortion and the detrimental morphological characteristics of fruit caused by a temperature of 40 °C

Comportamiento agronómico y fisiológico de maíces nativos del sureste de México

México es el centro de origen y domesticación del maíz (Zea mays L.), en algunas regiones aún existen poblaciones criollas con potencial para generar variedades mejoradas. El objetivo de este estudio fue evaluar el comportamiento agronómico y fisiológico de doce poblaciones de maíz nativas del sureste de México. El experimento se realizó en Tizimín, Yucatán en el año 2017. Se evaluaron 32 parámetros correspondientes a variables vegetativas, fenológicas, agronómicas y fisiológicas. Los resultados mostraron una diferencia de 75 cm entre las plantas más bajas (Xn-69) y las de porte más alto (CNB), las plantas de la población DZ-252 presentaron mayor follaje (19.1 hojas) y mayor diámetro de tallo (26 mm), las poblaciones más precoces fueron CM y CCB (65.5 y 65.8 días, respectivamente). El 58% de las poblaciones evaluadas superó el rendimiento promedio de la región (4.5 t ha-1). El mayor rendimiento lo obtuvieron las poblaciones CM, Cro, H1 y SP2015 (117.7, 105.8, 111.5 y 109.5 g planta-1, respectivamente). Las poblaciones CM, DZ2015, Cja y Cro tuvieron mayor tasa fotosintética; sin embargo, la mayor eficiencia del uso del agua lo presentaron las poblaciones DZ-252 y XnQroo (8.9 μmol CO2/mmol H2O). La población CM destacó por su rendimiento y precocidad, la DZ-252 podría utilizarse como forraje por la cantidad de biomasa que generó y la XnQroo debería ser estudiada bajo condiciones de restricción hídrica por su eficiencia del uso del agua, estas tres poblaciones deberían incluirse en programas de mejoramiento genéticoMexico is the center of origin and domestication of maize (Zea maysL.), in some regions there are still creole populations with the potential to generate improved varieties. The objective of this study was to evaluate the agronomic and physiological behavior of twelve maize populations native to southeastern Mexico. The experiment was carried out in Tizimín, Yucatán in 2017. 32 parameters corresponding to vegetative, phenological, agronomic and physiological variables were evaluated. The results showed a difference of 75 cm between the lower plants (Xn-69) and those of higher bearing (CNB), the plants of the population DZ-252 presented greater foliage (19.1 leaves) and greater stem diameter (26 mm), the earliest populations were CM and CCB (65.5 and 65.8 days, respectively). 58% of the populations evaluated exceeded the average yield of the region (4.5 t ha-1). The highest yield was obtained by the CM, Cro, H1 and SP2015 populations (117.7, 105.8, 111.5 and 109.5 gplant-1, respectively). The populations CM, DZ2015, Cja and Cro had a higher photosynthetic rate; however, the highest water use efficiency was presented by the DZ-252 and XnQroo populations (8.9 μmol CO2/mmol H2O). The CM population stood out for its performanceand precocity, the DZ-252 could be used as fodder for the amount of biomass it generated and the XnQroo should be studied under conditions of water restriction for its efficiency of water use, these three populations should be included in breeding program

Structure and Genetic Diversity of Nine Important Landraces of Capsicum Species Cultivated in the Yucatan Peninsula, Mexico

Mexico has a wealth of Capsicum species, which has led to the development of a large number of chili pepper landraces. A great wealth of Capsicum germplasm can be found in southern Mexico in the Yucatan Peninsula, an important area of diversification of Capsicum annuum. Specifically, in the western Yucatan Peninsula, three of the five domesticated species of Capsicum (C. annuum, C. chinense and C. frutescens) have been reported. However, information on their genetic diversity, conservation status and potential use is lacking. To generate useful information toward the sustainable use, management and conservation of these species, we evaluated the structure, diversity and genetic relationships of nine accessions of Capsicum spp., of major importance cultivated in the western Yucatan Peninsula using 42 ISSR loci. The results indicated that these accessions consisted of three genetic groups that were defined by the respective species of each accession. The level of genetic diversity was moderate and distributed mainly among accessions. The ISSR markers detected a high level of polymorphism and allowed the genetic differentiation of the C. annuum complex. The results indicated that the accessions collected in the western Yucatan Peninsula constitute a valuable genetic resource that can be used in genetic improvement and conservation programs

Caracterización morfológica de semillas de frijol caupí (Vigna unguiculata L. Walp) de la Península de Yucatán

The cowpea (Vigna unguiculata (L) Walp) is an important crop in several regions of the world, but in Mexico it is little used. The characterization of agricultural varieties has been based on morphological descriptors, including seed shape, color and size, as well as quantitative attributes such as mineral content. The aim of this research was to evaluate the morphological and nutritional characteristics of cowpea genotypes from the Yucatan Peninsula, Mexico. Fifteen collections were made from October 2017 to January 2018 and then evaluated for three qualitative morphological variables and 10 quantitative ones. The content of potassium, calcium, manganese, iron and zinc was determined by means of micro X-ray fluorescence. An analysis of variance and principal components were performed. Eighty percent of the collections have an ovoid shape, 73% a smooth to rough texture and 80% are black. In the quantitative morphological variables, 53% of the collections were considered to have small seeds, 40% medium and 7% large. The length, width and thickness of the genotypes were from 6.26 to 9.56, 3.64 to 7.48 and 2.86 to 5.56 mm, respectively, and the PET15 collection was the smallest. For mineral content, the OXC04 collection had the highest concentration of Ca, Mn, Fe and Zn, while the PET07 collection had the highest K content. There are high levels of phenotypic diversity in the collections studied and they are grouped based on their physical characteristics and not on their place of origin.RESUMEN El frijol caupí (Vigna unguiculata (L) Walp) es un cultivo importante en varias regiones del mundo, pero en México no es muy explotado. La caracterización de variedades agrícolas se ha basado en descriptores morfológicos, en los que se incluyen: forma, color y tamaño de semilla, además de atributos cuantitativos como el contenido mineral. El objetivo del trabajo fue evaluar las características morfológicas y nutricionales de genotipos de frijol caupí de la Península de Yucatán, México. Se realizaron 15 colectas de octubre 2017 a enero 2018, a las que se evaluaron tres variables morfológicas cualitativas, 10 variables cuantitativas y se determinó el contenido de potasio, calcio, manganeso, hierro y zinc, mediante µ-fluorescencia de rayos-X. A los datos se les realizó un análisis de varianza y de componentes principales. El 80% de las colectas tienen forma ovoide, 73% textura suave a áspera y el 80% son de color negro. En las variables morfológicas cuantitativas, 53% de las colectas se consideran pequeñas, 40% medianas y 7% semillas grandes. La longitud, ancho y espesor de los genotipos fue de 6.26 a 9.56, 3.64 a 7.48 y de 2.86 a 5.56 mm, respectivamente, la colecta PET15 fue la de menor dimensión. Para el contenido mineral, la colecta OXC04 tuvo la mayor concentración de Ca, Mn, Fe y Zn, mientras que la colecta PET07 presentó mayor contenido de K. Hay altos niveles de diversidad fenotípica en las colectas estudiadas y se agrupan con base en sus características físicas y no al lugar de origen

Kinetics of Macro and Micronutrients during Germination of Habanero Pepper Seeds in Response to Imbibition

The aim of this study was to evaluate the concentration and distribution of a number of macro- and micronutrients in response to imbibition in habanero pepper seeds extracted from fruits with different stages of maturity and postharvest storage times, as well as in their seedlings. Fruits were harvested unripe, half-ripe, and ripe, and were subjected to storage for 0 (control), 7, and 14 days postharvest prior to seed extraction. An X-ray microfluorescence analysis was carried out on seeds pre- and post-imbibition, as well as on seedlings at 10 and 14 days after sowing. K, Ca, Fe, P, Mg, and Mn were detected by elemental analysis. The results indicated that the elements had a higher concentration and distribution in seeds extracted from half-ripe fruits and ripe unstored fruits, as well as in seeds extracted from fruits stored for 7 and 14 days postharvest. K and Ca were the elements with the highest distributions and concentrations in seeds and seedlings pre- and post-imbibition compared to the other elements. At all maturity stages, postharvest storage increased the concentration and distribution of mineral nutrients in seeds and seedlings before and after imbibition. Storage translocated mineral elements to the radicle before germination, increased meristem growth in emerged seedlings, decreased electrical conductivity, and increased germination. Fourteen days of postharvest storage increased the distribution of macro- and micronutrients in immature seeds, decreasing electrical conductivity, potentiating germination, and improving mineral element distribution in seedlings