Search

The wild diversity of the Coffea genus is large, which is valuable for coffee plant breeding programs intended to obtain higher sensory quality varieties; but a biochemical characterization of accessions, already available in coffee germplasm banks, is still needed. In this work, a quantitative determination of caffeine, trigonelline and 5-caffeoylquinic acid (5-CQA), in coffee leaves of 80 different Coffea spp. accessions from the Coffee Germplasm Bank located in Huatusco, Veracruz, Mexico was done. These metabolic variables might be useful as quality-related selection markers in future coffee breeding programs. Fresh coffee leaves from each accession were processed and metabolites determined by UPLC-MS/MS analyses. Multidimensional Scaling (MDS), Hierarchical Cluster Analysis (HCA) and Analysis of Variance (AOV) revealed that levels of caffeine and trigonelline in leaves significantly varied among accessions, from 0.00 to 2.04% (w/w) and from 0.42 to 1.82% (w/w), respectively. While 5-CQA ranged from 0.00 to 0.66%. In C. liberica no caffeine was detected, demonstrating that coffee leaves have the potential to be used in the genetic profiling of Coffea spp. These results could be useful in formulating a proposal for intraspecific crosses in C. arabica, for the generation of F1 hybrids with good cup quality attributes, while in C. canephora they could be helpful for enhancing sensory quality traits of Robusta coffees.

The Coffea genus includes about 124 species, of which Coffea arabica L. and Coffea canephora Pierre ex A. Froehner are the most commercially important, supplying 63 and 37% of the world coffee production, respectively. C. arabica L. is associated with better cup quality, but presents serious problems with pests and diseases, potentiated by climate change. The development of new varieties of C. arabica L. requires the inclusion of genetic diversity, looking for incorporating new genes to tolerate or resist the most important pests and diseases, maintaining or improving yield and cup quality of the new materials. The technology of diversity arrays based on sequencing (DArTseq™) allows the rapid identification of the single nucleotide polymorphism (SNP) for a genomic approach of genetic diversity. The objectives of the present study were: (1) to evaluate the diversity and genetic structure of a central coffee collection of the Mexican National Bank of Coffee Germplasm; (2) assess the reproducibility and error rates of the markers and their broad representation in the genome and (3) to propose a new collection with representative and divergent promising genotypes for stablishing a coffee breeding program in Mexico. 87 coffee accessions of three different species of the Coffea genus were sequenced and 16,995 SNP markers were derived from 34,000 unique sequences obtained by the DArTseq™ method. After removing the markers with more than 10% of missing data and the MAF

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.

Heliconia es un género que agrupa a especies tropicales y subtropicales; se distribuye de manera natural desde Brasil hasta México; la vistosidad de su inflorescencia permite su uso con fines ornamentales. Estudios cariológicos en Heliconia reportan especies con 2n = 2x = 22, 2n = 2x = 24 y 2n = 3x = 36 cromosomas. Debido a que en las especies de México se desconoce el número y morfología cromosómica, el presente estudio tuvo por objetivo determinar el cariotipo de Heliconia uxpanapensis, endémica de México, H. latispatha y H. stricta cv. Iris. El pretratamiento de las raíces se realizó con un medio físico (4 ± 1 ºC). El genoma haploide de H. uxpanapensis mide 22.21 μm, el de H. latispatha 26.56 μm y el de H. stricta 25.37 μm. Las tres especies tienen 2n = 2x = 24 cromosomas, la fórmula cariotípica de H. uxpanapensis está representada por 2n = 8m + 10sm (2sat) + 6st, el de H. latispatha 2n = 4m + 14sm + 6st (2sat) y el de H. stricta 2n = 16m + 8sm. El primero y segundo par de cromosomas de H. latispatha y H. uxpanapensis, respectivamente, presentan satélites, mientras que en H. stricta la presencia del satélite se observó en un solo cromosoma del genoma. Este es el primer estudio en el género Heliconia que reporta la presencia de cromosomas subtelocéntricos.

El uso de técnicas de marcadores moleculares se inicia con un buen extracto de ADN; esto es, un ADN con buen rendimiento y pureza. Con la finalidad de obtener ADN puro e íntegro, en el presente estudio se evaluaron seis métodos de extracción de ADN: Dumolin, Doyle, Tsumura, Núñez, CTAB modificado y Kit Wizard Genomic DNA en brotes frescos y liofilizados, así como en hojas deshidratadas de tejocote (Crataegus mexicana Moc. & Sessé). La mejor calidad de ADN se obtuvo con los métodos Doyle y CTAB, mientras que los mayores rendimientos fueron con el Kit y con el método Doyle. Así mismo, se encontró que el material vegetal liofilizado proporcionó mayor rendimiento en todos los protocolos en los brotes frescos y hojas deshidratadas. En la verificación mediante PCR se encontró que el gen ribosomal 16S podía ser fácilmente amplificado con los protocolos de Doyle, CTAB modificado y el kit comercial.

Entre las enfermedades importantes del cultivo de chile (Capsicum annuum L. ) se encuentra la “marchitez” (Phytophthora capsici L.). Como en otras enfermedades, la resistencia genética es una estrategia importante para su control. Una de las fuentes donde se pueden encontrar genes de resistencia son los materiales criollos. En evaluaciones previas se han encontrado colectas de chile Huacle con resistencia a dicho patógeno. En el presente estudio se determinó la herencia de la resistencia a P. capsici de las líneas de chile tipo Huacle 33.3, 34.1 y 35.3. Se generaron poblaciones F2 de las cruzas de las tres líneas con la variedad susceptible NuMex Joe E. Parker. La determinación de similitud entre los genes de resistencia de las líneas 33.3 y 35.3 se hizo mediante las cruzas directa y recíproca entre ellas y se generaron poblaciones F2. Las poblaciones F2 se inocularon con aislados de P. capsici, que en evaluaciones previas se comportaron como avirulentas a las tres líneas progenitoras tipo Huacle y virulentas a la variedad susceptible. Las plántulas segregantes en F2 fueron clasificadas en resistentes y susceptibles de acuerdo con una escala de severidad de 1 a 7, y se analizaron con una prueba de Ji-cuadrada para determinar el número de genes de resistencia presentes en cada línea. Las líneas 33.3 y 35.3 mostraron una segregación 3:1 de plantas resistentes y susceptibles, lo que indica la presencia de un gen distinto en cada una de ellas, resultado que se confirmó con la segregación 15:1 obtenida en las poblaciones F2 de las cruzas entre estas líneas. La línea 34.1 presentó dos genes de resistencia dominantes, debido a la segregación 15:1 en la población F2 entre plantas resistentes y susceptibles.

Tomato (Solanum lycopersicum L.) is one of the most economically important vegetables in the world. Mexico is considered as its center of domestication and there is a large genetic diversity. Grafting in tomato has grown for various purposes including the increase of yield. An alternative use of native tomato genotypes is as rootstocks for grafting improved tomato. The objective of this work was to evaluate native accessions of tomato as rootstocks to identify outstanding genotypes for their potential to be used as rootstocks in tomato production. An experiment was conducted for two cropping cycles (2014 and 2015) in greenhouse and hydroponic conditions, in a randomized complete block design (RCBD) with three replicates and 10 plants per experimental unit. Treatments were formed by a combination of nine native tomatoes and two commercial rootstocks with two hybrids used as scions. Twelve traits were recorded and most of the treatments were significantly different (P < 0.05) from each other for these traits. The accessions LOR-22, LOR-77, LOR-81, LOR-84, LOR-95 and LOR-100 with the hybrid ‘El Cid’, and LOR-81, LOR-84 and LOR-100 with the hybrid ‘Sun 7705’, increased significantly yield by 19% and 22%, respectively, compared to ungrafted control. Moreover, characteristics related to fruit quality were preserved with grafting. The best combination scion/rootstock (‘Cid’/100) yielded 30% higher than hybrid ‘El Cid’ without grafting and 16% higher than the commercial rootstock ‘Multifort’. This allowed identifying genotypes of Mexican native tomatoes with great potential to be used as rootstocks or as source of germplasm for rootstock development.

Hunger and malnutrition still affecting part of the Mexican population, for whom the tortilla is a staple food. However, maize tortillas are high in calories but deficient in proteins; therefore, studies have been conducted to fortify tortillas, with protein-rich nonconventional sources. This study examines the physicochemical and rheological characteristics of dough and maize tortillas fortified with nontoxic Jatropha curcas flour. Fortified maize doughs were prepared with 0%, 5%, 10%, 15% and 20% J. curcas nontoxic flour, which contains 55% protein. Tortillas were made and their chemical profile and tortilla quality were quantified and subjected to sensorial analysis. Rheological characteristics of dough were slightly modified but the protein in the tortillas increased 10.8% with treatment T20. They did not change in color, were soft, and consumer acceptance was not affected. It is concluded that nontoxic J. curcas flour is an excellent option for increasing the protein value of tortillas.

The oomycete P. capsici is among the major pathogens found in pepper. A desirable, sustainable and environmentally-compatible way to manage it is through genetic resistance. Huacle and Serrano pepper lines resistant to P. capsici isolate 6143 have been detected; however, it is necessary to determine whether the resistance of these lines is effective against a higher number of isolates and evaluate their resistance to other important pathogens, such as root-knot nematodes. The aim of this study was to evaluate the resistance of Huacle and Serrano pepper lines to different P. capsici isolates and root-knot nematodes (M. incognita and N. aberrans). Ten P. capsici isolates from different pepper-growing regions, and two independently-inoculated nematode populations, one of M. incognita and the other of N. aberrans, were used. Serrano pepper, lines 41-1, 41-2, 42-6 and 55-2 stood out, with a resistance response to all P. capsici isolates followed by Huacle pepper lines 33-3, 35-3 and 34-3, which were only susceptible to one isolate. Furthermore, except for lines 34-3, 35-5 and 42-2, all the others were resistant to M. incognita. Serrano pepper lines 41-1, 41-2 and 42-2 and Huacle lines 35-3 and 35-5 were resistant to N. aberrans, while lines 41-1, 41-2 and 35-3 lines were resistant to the three pathogens evaluated. Resistance previously detected in Huacle and Serrano peppers is effective for different P. capsici isolates and root-knot nematodes.

Garlic is an apomyctic diploid species (2n=2x=16) with vegetative reproduction that belongs to the Allium genus (Alliaceae), which includes onion (Allium cepa), leek (A. ampeloprasum) and shallot (A. ascalonicum) (Mc-Collum, 1987; Figliuolo et al., 2001; Ipek et al., 2003; 2005). The importance of garlic was recognized by humans at bronze era about 5000 years ago, and since these early times, has been used as food, condiment and medicine by Asians and Mediterranean (Ipek et al., 2005). World production of garlic is ranked 14th among vegetables with a total of 14.5 million ton (Trejo, 2006). In Mexico, its consumption is about 400 g per capita (Chavez, 2008), and the national production is considered low as compared to other countries such as China (80 % world production), India, Korea and the rest of the world (20 %) (FAOSTAT, 2011). Still, Mexico has a place as exporter of garlic produced mainly from the states: Zacatecas, Guanajuato, Aguascalientes, Baja California, Puebla and Sonora (Trejo, 2006). The areas in Mexico during winter 2008, dedicated to garlic were 5,085 ha with a total yield of 49,968 ton (SIAP, 2011).

El objetivo del estudio fue caracterizar la variabilidad morfológica en hojas de árboles de nanche (Byrsonima crassifolia (L.) H. B. K.) de la Sierra de Tabasco, México. En 39 accesiones se muestrearon hojas desarrolladas de la estación, y se seleccionaron 10 hojas representativas de cada una para ser evaluadas mediante análisis de imagen con 17 caracteres. Tres componentes principales explicaron 77.28 % de la variabilidad total. Con una distancia euclidiana de 0.07 en el dendrograma, se formaron cinco grupos con caracte-rísticas morfométricas similares. Los caracteres que mejor explican la variabilidad fueron: longitud del eje menor, índice de redondez, ángulo basal, ángulo de la quinta vena, relación longitud del eje mayor del limbo/longitud del eje menor, relación longitud del eje menor/longitud del pecíolo y relación ángulo basal/ángulo de la quinta vena.