Carlos Alberto Núñez-Colín

Distribution and agroclimatic characterization of potential cultivation regions of physic nut in Mexico

Os objetivos deste estudo foram determinar a distribuicao e os padroes climaticos de regioes de cultivo, atuais e futuras, do pinhao-manso no Mexico, e identificar possiveis locais para o estabelecimento de bancos ativos de germoplasma, com uso de sistemas de informacao geografica. Os dados climaticos atuais foram processados pelo software Floramap, para obter mapas de distribuicao e padroes climaticos de regioes onde plantas de pinhao-manso selvagens poderiam ser encontradas. Foi utilizado o software DIVA-GIS para analise dos dados climaticos atuais (modelo Worldclim) e dos dados climaticos gerados pelo modelo CCM3, para identificar regioes de cultivo atuais e futuras de pinhao-manso, respectivamente. O pinhao-manso esta distribuido na maioria das zonas tropicais e subtropicais do Mexico, que correspondem a tres regioes agroclimaticas. Os tipos climaticos foram Aw2, Aw1 e Bs1 para as regioes 1, 2 e 3 respectivamente. Genotipos nao toxicos foram associados a regiao 2, e genotipos toxicos foram associados as regioes 1 e 3. De acordo com as regioes de cultivo atuais e futuras identificadas, as mais adequadas para o estabelecimento de colecoes in vivo de germoplasma sao a costa de Michoacan e o Istmo de Tehuantepec, localizadas entre os estados de Veracruz, Oaxaca e Chiapas.

Morphological response and fruit yield of sweet pepper (Capsicum annuum L.) grafted onto different commercial rootstocks

In attempts to phase out the use of methyl bromide as a fumigant, the grafting of sweet pepper may be used in integrated disease management to produce the fruit safely in an environmentally friendly way; however, there has been controversy as to whether the use of the graft affects the fruit yield. Therefore, the aim of this study was to evaluate the morphological characteristics and yield of marketable fruit of the pepper cultivar Triple Star grafted onto eight rootstocks. Ninety percent of the variability in the agronomic and morphological characteristics of non-grafted and grafted Triple Star individuals was explained by the first three canonical roots, in which discriminating characteristics of weekly and total fruit yield, number of fruits harvested per m2, leaf length, plant growth, number of nodes on the main stem, stem diameter, and distance from the apex to the last open flower were prominent. Except for this last characteristic, for which no significant differences between the rootstocks were found, the CM334 rootstock negatively affected all of the agronomic and morphological characteristics, whereas rootstock AR96029 had a positive effect by significantly increasing the plant growth and yield. Additionally, the Tresor rootstock induced an increase in the leaf length and number of marketable fruit without increasing the fruit yield. This evidence indicates that the rootstock had a significant influence on the morphological and agronomic characteristics of the scion. For the production of peppers, therefore, the proper selection of rootstock prior to performing the graft is suggested.

Priority areas to collect germplasm of Malacomeles ( Rosaceae ) in Mexico based on diversity and species richness indices

The genus Malacomeles (Decne.) G. N. Jones (Rosaceae subtribe Pyrinae) represents several fruit shrubs, which is mainly distributed in North and Central America, from southern USA to Honduras and Guatemala, although the main distribution of this genus is in Mexico. Five species of the genus Malacomeles have been reported to exist in Mexico. Malacomeles is widely distributed in several mountainous ranges in Mexico, although it is unknown where most of the diversity of the Malacomeles genus is located in the country. The aim of this biogeographic study was to determine the areas of highest diversity of the genus Malacomeles in Mexico based on species richness and diversity indices in order to identify the best regions of Mexico to collect germplasm. The results indicated that most of the diversity of the genus Malacomeles is concentrated in northeast Mexico, mainly in the biogeographic province of Sierra Madre Oriental. In this province, the highest values on three biodiversity indices were found. Thus, this area can be considered as the priority area to collect the germplasm of Malacomeles. M. denticulata is the predominant and the most interesting species in Mexico from the viewpoint of collecting plant genetic resources; this species is mainly distributed in the provinces of Trans-Mexican Volcanic Axis, Mexican Plateau and Sierra Madre del Sur, where secondary priority areas to collect germplasm are located.

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.

Caracterización Genética de Spodoptera frugiperda (Lepidoptera: Noctuidae) en México Usando Marcadores AFLP

Resumen. En el presente estudio se caracterizó genéticamente al gusano cogollero colectado en 10 estados de México, mediante marcadores AFLP (Polimorfismo en la Longitud del Fragmento Amplificado). Se detectaron altos niveles de polimorfismo (98%), además el análisis de las relaciones genéticas y el índice de diversidad de los datos moleculares indicaron amplia variabilidad genética de esta especie. Se formaron dos grupos de genotipos de S. frugiperda en el dendrograma de las relaciones genéticas, confirmando la presencia de dos razas que podrían haber desarrollado diferencias biológicas y fisiológicas. No se observó la agrupación por origen geográfico, por lo que se concluye que la variación genética identificada se asocia más con la presencia de las razas maíz y arroz, que con el origen geográfico de los especímenes. La combinación E-ACT+M-CAC fue la más eficiente para estimar las diferencias entre especímenes y separar ambos grupos de genotipos de S. frugiperda, ya que tuvo los valores de MI (80.52), RP (112.27), y PIC (0.297) más altos, así como una correlación alta y significativa entre PIC y MI (r2 = 0.91, p < 0.05), y entre RP y MI (r2 = 0.99, p < 0.05).

Effect of drying on antioxidant capacity, physicochemical and functional characteristics of Mexican serviceberry fruit

BACKGROUND: There are five species of Malacomeles (family Rosaceae) endemic in America. They grow from southern Texas to north Honduras. Of those five species, M. denticulata (Mexican serviceberry) is the most widely distributed in Mexico. OBJECTIVE: To increase knowledge of how drying method affect physical and chemical characteristics of Mexican serviceberry fruit. METHODS: Fruit was dried through the process of sun-, shade- or hot air. Vitamin C, total phenols, condensed tannins, anthocyanins, simple phenols, Trolox equivalent (TEAC) and oxygen radical antioxidant (ORAC) capacities were determined in serviceberry raisins. RESULTS: Titratable acidity, Brix, calcium, iron, and condensed tannins were higher in shade-dried raisins. The total phenolics ranged from 389.2 to 434.2 mg eq. gallic acid/100 g and were in the range reported for grape raisins. Total fiber was up to 4-fold higher in serviceberry raisins compared to those of grape raisins. Calcium and iron contents were on average 4.3- and 55-fold higher, respectively, compared with that reported for grape raisins. -Shade-dried, sun-dried and hot air-dried serviceberry raisins showed by far, higher Trolox equivalent compared to oxygen radical antioxidant capacity. CONCLUSION: Shade drying process is economic and advantageous. It helps to extend the Mexican’s serviceberry fruit shell, preserving the fruit’s outstanding functional characteristics.

Mucilage from cladodes of Opuntia spinulifera Salm-Dyck: chemical, morphological, structural and thermal characterization

ABSTRACT The mucilage obtained from cladodes of Opuntia spinulifera has been used in industries and traditional applications. In the present work, the chemical, morphological, thermal and structural features of cladode mucilage from Opuntia spinulifera Salm-Dyck were studied. The 2D 1H-1H COSY NMR confirmed ten different residues within the repeating saccharide unit, six with α and four with β configurations. The FTIR showed the presence of galactose and pectins. The XRD detected minerals as calcium salts. The SEM exhibited aggregations and irregular morphology of the particles. The TGA registered the highest mass loss between 246–378°C and the DSC showed the transition state at 55.7°C and at 113.2°C was observed the typical endothermic peak, where it corresponds to the organic compound materials.

A new allele of γ‐kafirin gene coding for a protein with high lysine content in mexican white sorghum germplasm

BACKGROUND Low protein digestibility and lysine content of white sorghum grain limit its use as a foodstuff. The increase in γ-kafirin cross-linking, has an important role in the reduction of protein digestibility. The objective of this study was to characterize the γ-kafirin gene in 12 Mexican tannin-free white sorghum genotypes and its relationship with protein digestibility and lysine content. RESULTS Two alleles of γ-kafirin gene were identified: alleles 1 and 7. The predicted amino acid sequence of allele 7 showed seven point mutations; six were silent, and one missense (C235G), causing the substitution P79A in the deduced amino acid sequence. In silico analysis showed that γ-kafirin codified by allele 1 has five α-helixes without disulfide bonds, while γ-kafirin coding by allele 7 has four α-helixes and three disulfide bonds. Genotypes with allele 7 had higher lysine content than those with allele 1, showing no differences in the kafirin electrophoretic profile, neither a correlation with the protein content nor the in vitro pepsin digestibility. CONCLUSIONS Mexican tannin-free white sorghum genotypes showed two γ-kafirin alleles, 1 and 7. Allele 7 was associated with higher lysine content; in silico analysis showed that the substitution of P79A in this allele could modify γ-kafirin secondary structure.

Adaptation of Cultivated Amaranth (Amaranthus spp.) and Their Wild Relatives in Mexico

In a global climate change scenario, climate-resilient varieties are needed. This research aimed to identify possible shifts in suitable zones of adaptation of two predominant cultivated Mexican species of amaranth (Amaranthus cruentus and A. hypochondriacus) and their two possible wild relatives (A. hybridus and A. powellii) using DIVA-GIS with two different climatic databases. The first model used a current climatic database named WorldClim. The second model accounted for global climate change to obtain the predicted future suitable regions of adaptation using a CCM3 model. This research was performed to elucidate the best possible suitable areas to establish plantations and in vivo germplasm banks, and to predict migration pattern of these species. Our research suggests that the cultivated species of amaranth and their wild relatives had differences among their current and predicted suitable regions of adaptation. Temperature would be the main climatic variable affected. In predicted model, all species examined were more frequent in regions with higher temperature when compared to the current model. However, only A. powellii had a change in annual precipitation frequency in both models. A. hybridus could be a potential new genetic source for amaranth adaptation to potential climatic regions because it showed wider adaptation than the cultivated species.