R. Nieto-Ángel

Flavonoids and antioxidant activity of flowers of Mexican Crataegus spp.

Flavonoids and antioxidant activity of extracts of flowers from some Mexican accessions of Crataegus were studied using six accessions with the purpose of contributing to the knowledge of the nutraceutical properties of the accessions of the Germplasm Bank of the Universidad Autonoma Chapingo. Flavonoids were identified by HPLC–MS. Among the flavonoids, the quercetin 3-O-glucoside (3), quercetin 3-O-rhamnoside (4), quercetin 3-O-rhamnosyl-(1 → 6)-glucoside (2) and quercetin 3-O-rhamnosyl-(1 → 2)-[rhamnosyl-(1 → 6)]-glucoside (1) were assigned. Flavonoid content and radical scavenging activity explain some of the medicinal properties attributed to flowers of Mexican hawthorns.

Variabilidad anatómica de los sistemas de conducción y estomático de genotipos de Prunus spp. de diferentes orígenes

The aim of this research was to study the relationships between environmental humidity availability and the anatomical characteristics of water conduction and stomatal systems, in five Mexican peach genotypes with different origins (Jalatzingo and Misantla, Veracruz; Temascaltepec, Mexico; Tulancingo, Oaxaca; Sombrerete, Zacatecas), one almond and Nemaguard rootstock. Shoots, leaves and stomata of six months old plants were anatomically characterized by means of 25 characters. The almond tree and the rootstock Nemaguard showed differences in relation to the peaches, which had higher similarity, although they maintained a separation according to their origin. Groups were differentiated by the following characters: stomatal density; width of the leaf upper epidermis; number, frequency and perimeter of xylem vessels; and the index of vulnerability of the leaf central vein, pith, xylem and phloem percentage of the shoot. The conditions of humidity availability of their origin showed strong association with the studied anatomical characteristics, because the environment with more deficit of humidity (Tulancingo and Sombrerete) showed plants with bigger size and smaller frequency of vessels of xylem, as well as low xylem and phloem percentage in shoot, which can be interpreted as resistance adaptations to drought. The area where the occurrence of drought (Jalatzingo) is rare showed the opposite characteristics.

Evaluación de Trampas y Atrayentes para el Monitoreo de Rhagoletis pomonella1 en Tejocote (Crataegus mexicana) en México

Resumen. El Tejocote (Crataegus spp.) es un árbol originario de México, de alto valor alimenticio ya que su fruta tiene un alto contenido de pectina que se consume en México y los EUA durante las celebraciones culturales y religiosas de fin de año. Una de sus principales plagas es la mosca de la fruta Rhagoletis pomonella, comúnmente conocida como mosca de la manzana, que puede infectar hasta 100% de sus frutos. El objetivo del estudio fue evaluar la eficacia de dos trampas con cuatro colores y dos atrayentes alimenticios para el monitoreo de la mosca de la fruta en plantaciones de Tejocote. Trampas pegajosas en forma de esfera y panel de color: amarillo, naranja, blanco y rojo, cebadas unas con Winner 360® y otras con GF-120® fueron evaluadas en tres plantaciones de Tejocote. Los datos de capturas fueron sometidos a un análisis multifactorial de varianza y a una separación de medias de Tukey para determinar que combinación de trampa es mejor para capturar adultos de R. pomonella. La mejor trampa para capturas de R. pomonella en Tejocote en el centro de México con fines de monitoreo, fue la tipo panel de color amarillo con atrayente proteína hidrolizada Winner 360® o GF-120®, con más capturas que las demás combinaciones.

Analysis of the biodiversity of hawthorn ( Crataegus spp.) from the morphological, molecular, and ethnobotanical approaches, and implications for genetic resource conservation in scenery of increasing cultivation: the case of Mexico

One hundred and forty Mexican hawthorn (Crataegus spp.) accessions from six regions are preserved at the BGT-UACH germplasm bank (Mexico), comprising the most comprehensive living collection of Mexican hawthorns with different degrees of human management. The objective of this study was to assess the biodiversity of this valuable collection from morphological, molecular (microsatellite), and ethnobotanical viewpoints in order to delineate the most adequate strategy for the conservation of the native hawthorn germplasm in the present scenario of incipient establishment of commercial hawthorn plantations, which is likely to increase. Molecular characterisation revealed that the biodiversity was chiefly (90%) placed within the regions. Morphological characterisation indicated that the group from Chiapas was the most different germplasm pool compared with the other five. This was confirmed by molecular analysis, because in spite of the lack of a phylogeographical pattern, two germplasm pools were detected: one composed mainly by accessions from Chiapas and the other mainly by accessions from the other regions. The only clear differences among the regions in the ethnobotanical study were those derived from putting hawthorns into commercial cultivation, which occurred in just one region in the centre of the country (Mexico–Puebla–Tlaxcala). As a consequence, an ex situ conservation programme is necessary for those regions shifting patterns of cultivation from traditional to commercial, regardless of whether other on-farm programmes are also implemented. The germplasm collections within each region must be exhaustive due to their high genetic diversity.

FIRST REPORT OF Botrytis cinerea CAUSING POSTHARVEST GRAY MOLD OF TEJOCOTE (Crataegus mexicana) FRUIT IN MEXICO

In Mexico, tejocote (Crataegus spp.) is grown commercially on a total area of more than 900 ha. During November and December 2013, fruits of Crataegus mexicana var. chapeado showing a gray and firm rot were collected in commercial markets in Puebla. Small pieces of decayed fruits were surface-disinfected for 1 min in a 2% sodium hypochlorite solution, rinsed in sterile distilled water, and plated onto potato dextrose agar (PDA). A fungus was isolated whose colonies were initially whitish but turned gray with age. Black and irregular sclerotia were formed after 14 days of incubation at 20°C. Conidiophores were erect, subhyaline and dichotomously branched, and bore unicellular, ovoid-ellipsoid, subhyaline conidia measuring 7.7-12.7x6.1-9.5 μm. Based on morphology, the fungus was identified as Botrytis cinerea. Genomic DNA was extracted and the internal transcribed spacer (ITS) region of rDNA was amplified using the universal primers ITS5 and ITS4 (White et al., 1990). PCR products were purified and sequenced. The resulting sequence of 496 bp was deposited in GenBank (accession No. KM594622). BLAST search showed 100% identity with B. cinerea sequences KF010847 and KJ476697. To confirm the pathogenicity of the fungus, 10 tejocote fruits were surface-disinfected with 80% ethanol. A conidial suspension (1x106 spores ml-1) was sprayed on the surface of non-wounded fruits. Control fruits were sprayed with sterile distilled water. Typical gray mold symptoms with gray sporulating lesions were observed only on inoculated fruits after eight days. Koch s postulates were fulfilled when the pathogen was re-isolated from the diseased fruits. To our knowledge, this is the first report of B. cinerea causing postharvest fruit rot on tejocote in Mexico and worldwide.

BRANCHING SYSTEM OF THE MEXICAN HAWTHORN "TEJOCOTE" (CRATAEGUS spp.)

Abstract The architecture of the tejocote (pronounciation: tehocote) - a Mexican fruit trees is described. There is a great morphological diversity among the tejocote clones growing in Germplasm Bank of the Autonomic University of Chapingo, Mexico. The common character of all hawthorns in this bank is that the inflorescence axis dies after shedding the reproductive parts (flowers or fruits) but remains on the tree, and the growth continues from the bud situated below the dead part. The growth and ramification habit were described as long shoots showing marked apical dominance and as the complex of shoots showing week apical dominance. The non-pruned trees of tejocote clones used as fruit trees form strong natural crown. The architecture of it is similar to the “Troll’s model” of Hallé and Oldeman (1970). Metamorphosis and reiteration are relatively frequent. The inflorescence structure was described, as well as the types of thorns in clones, which have thorns. Tejocote hawthorn may probably be an interesting fruit tree for countries with warm climate and a long dry period. It is also well adapted to shallow calcareous soils.