A sub-caducifolious growth habit, among other morphological and physiological traits, is the main adaptive advantage that allows acceptable production of ilama, up to 10 kg per tree, under dry tropical conditions of Guerrero, without any type of agronomic management; therefore, we intended to validate the production technology used in caducifolious fruit trees, evaluating the response of ilama to such management under the agroecological conditions of the region in question. In an essay evaluating promoters of defoliation-budding, the application of 100 g·liter-1 of urea had the best results. In the management experiment, the number of new buds per tree increased as a response to defoliation; irrigation also increased the number of flowers per branch, fruits per tree and the percentage of final fruit setting; while pruning increased fruit firmness, but decreased the content of reduced nitrogen and the number of fruits per tree. These results indicate the feasibility of managing ilama under dry tropic conditions, using an intensive production system that includes defoliation and irrigation practices.

An anatomic polyembryony study was carried out in the citrus rootstocks: Citrus reshni Hort. ex Tan. (Chleopatra Tangerine); C. volkameriana Pasq. (Volkameriana Lemon), and C. amblycarpa Ochse (Amblicarpa Tangerine). We found that, for the three species, the embryos are anatropous, crassinucelated and bitgemic. Nucellar embryos from the three rootstocks began developing even though their ovules had not been fecundated. Embryocytes (nucellar small embryos) were seen immersed in the nucella after the initiation of the megagametogenesis. Probably, the initiation of asexual embryos is independent from the development of an embryo of sexual origin; because, in some cases, we observed embryocytes without the presence of an endosperm or a zygotic or sexual embryo. Nucellar embryos differed in their developmental stages, because, within the same seed we found the stages early globular, late globular, and heart-shaped. Embryos were located in the micropilar extreme of the embryo sac in the lateral areas next to the micropile; this made it difficult to identify the origin of such embryos. Beginning at the globular stage, nucellar embryos presented the suspensor.

Obtaining quality seedlings for production of tomatillo is important, because the production process of this horticultural crop involves transplanting to accomplish a uniform and fast plant establishment and to reduce the crop production cycle. This study was carried out in Chapingo, Mexico, with the aim of evaluating the effect of three substrates (coconut fiber, peat moss, vermicompost) and two plastic colors (black and silver) on the emergency rate and growth of tomatillo seedlings under greenhouse conditions in uncovered and covered plastic trays. Treatments were established under a completely randomized experimental design with four replications. The following variables were evaluated at the seedling stage: plant height, number of leaves, fresh and dry weight in samples taken at 15, 22, and 30 days after seeding (das), stem diameter and nutrient content sampling at 30 das. Peat moss and coconut fiber, regardless of plastic utilization or color, resulted in higher rates for seedling germination and emergency. These substrates allowed the development of seedlings with better transplanting characteristics. Nutrient absorption was not affected by substrates.

The degree of ripeness of berries is associated to their anthocyanin content. The objectives of this study were to determine the effect of location and degree of ripeness on the anthocyanin content and antioxidant activity of raspberry fruits. We used the variety ‘Autumn Bliss,’ grown in Tlamimilolpa, Hidalgo and in San Mateo Acatitlan, Mexico. The degree of fruit ripeness was established by their pink (GM1), red (GM2) and red (GM3) coloration. The variables evaluated were: moisture (by difference in weight), color (Hunter-Lab), total anthocyanin content (CTA) using a colorimetric conventional method, and antioxidant activity (AA) by the DPPH radical method. The degree of fruit ripeness affected their color, total anthocyanin content and antioxidant activity. Location influenced anthocyanin content in degrees of ripeness GM1 and GM2, but not in fruits from GM3. Antioxidant activity of fruits with GM1 and GM2 degrees of ripeness was lower than that observed in GM3 ones. According to these results, to optimize the beneficial effect of raspberry consumption, fruits should be consumed when they show an intense red coloration (GM3).

There is a lack of basic knowledge on nopal cactus nutrition that would help to increase its productivity. In this context, we used the technique of Compounded Nutrient Diagnosis (DNC) to define preliminary norms for nutrition in nopal cactus (Opuntia ficus-indica L. Miller), based on the cubic relation between yields and accumulated variance proportion functions, as well as the c2 distribution function of global nutrition indices. We considered a database that included 180 yield observations (as cladode fresh weight per plant) and the of N, P, K, Ca and Mg concentrations (%) in one-year-old cladodes. Biomass yield of nopal cactus depends significantly on N (P£0.01), K (P£0.05) and Mg (P£0.05) concentrations. We observed the following significant synergisms: P-K (P£0.05), K-Mg (P£0.01) and Mg-Ca (P£0.01); and the antagonisms: N-Ca (P£0.01) y N-Mg (P£0.05). The DNC preliminary proposed norms expressed as logarithms of the centered proportions (mean ± standard deviation) for d = 5 nutrients, based on a high-yielding (more than 46.7 kg·plant-1 nopal cactus cladodes grown in a calcareous soil) sub-population (n = 57) are: = -0.98 ± 0.35, = -2.23 ± 0.21, = 0.25 ± 0.19, = 0.37 ± 0.35, = -0.71 ± 0.17, and = 3.29 ± 0.09. These norms correspond to the following ranges of optimal concentrations (mean ± standard deviation) in the cladodes: 1.29 ± 0.47 of N (%), 0.36 ± 0.08 of P (%), 4.24 ± 0.88 of K (%), 4.96 ± 1.73 of Ca (%) and 1.61 ± 0.27 of Mg (%). Nopal cactus concentrates more than four times K and Ca than N, proving that it is a calcitrophic plant. Something similar occurs between Mg and P, because the former is four times higher in concentration than the latter.

El volumen de la copa bien iluminada es uno de los principales factores en la productividad de árboles de árboles de nogal pecadero. Cuando las huertas adultas de nogal pecadero con altas densidades de plantación (al menos de 100 árboles por hectárea) presentan entrecruzamiento, la penetración de radiación fotosintéticamente activa dentro de la copa del árbol y entre árboles, el crecimiento y la producción de nuez son negativamente afectadas. La investigación realizada para estudiar el efecto del aclareo de árboles de nogal pecadero sobre la disponibilidad de la luz y productividad de la huerta es limitada. El objetivo del presente experimento fue determinar el efecto del aclareo de árboles sobre la disponibilidad de radiación fotosintéticamente activa (RFA) dentro y entre árboles permanentes, el crecimiento del brote, la densidad foliar, la producción y calidad de la nuez. Este estudio fue llevado a cabo en una huerta adulta de nogal pecadero con aclareo gradual de árboles de 25 a 50 %, durante el periodo 1995-1997. La disponibilidad de RFA dentro y entre árboles, la longitud de brotes, la densidad foliar y la producción por árbol fueron afectadas por los tratamientos de aclareo; sin embargo, la calidad de nuez (porcentaje de almendra) por árbol durante el periodo de tres años de estudio, no fue afectada significativamente. Los resultados de este estudio indican que un gradual aclareo de la huerta debe realizarse en el momento apropiado de edad de la misma, para evitar una drástica reducción en la producción de nuez.

Organic production of food is an alternative for consumers that prefer food free from pesticides and synthetic fertilizers and with high nutritional value. In Mexico, organic cherry tomato reaches a price 3.31 times higher than the conventional one; producing this type of tomato in the greenhouse would increase yield and, consequently, the economic benefit for the producer; however, organic certification requires a transitional period of three to five years without the application of any synthetic product to the soil. Utilization of an organic substrate would considerably reduce the transition period or would avoid it. The substrate, aside from anchoring the plants, should provide considerable amounts of nutritive elements satisfying the crop’s demands. One alternative is to mix compost with inert media. Therefore, the objective of the present study was to evaluate cherry tomato var. 647 under different compost mixtures with different combinations of sand or perlite under greenhouse conditions. The experiment was carried out in Matamoros, Coahuila, Mexico, at La Laguna Experiment Station of INIFAP. Main results indicated that the best four mixtures were: vermi-compost at 50 % with sand and vermi-compost with perlite at 25, 37 and 50 %, with an average of 48.507 t·ha-1; that is, we obtained better yields from those resulting from cherry tomato organic production in the field, without affecting fruit quality.

We applied salicylic acid (AS) 10-6 M, benzoic acid (AB) 10-6 M and chitosan (Q) 1 % solutions, which act as controlled oxidation promoters (POC) on chard (Beta vulgaris L.), cv. Fordhock, cauliflower (Brassica oleracea var. Botritis), cv. Snow Ball, broccoli (Brassica oleracea var. Italica), cv. Di Cico and cabbage (Brassica oleracea var. Capitata) cv. Copenhagen Market, grown in the greenhouse during the spring 2004. The objective was to determine the effects of these compounds on phenotypic traits and antioxidant levels in horticultural plants. The traits evaluated were: plant height, root length, number of leaves, fresh and dry weight, and antioxidant levels; the latter was determined using the method reported by Miller et al. The influence of the POC did not show a consistent trend in most of the variables. Plant height and root length were not affected in any of the horticultural plants; leaf number increased only in cabbage when applying AB. Total and aerial portion fresh weight was only higher in cabbage when AB was applied. Root dry weight increased in chard when applying AB; the compounds induced lower root weight in cabbage. Only chard and cabbage showed and increase in total antioxidant ability as a response to applications of AS and Q, respectively. Cabbage did not show any effect of the compounds on antioxidant levels; while broccoli showed a decrease in total antioxidant ability.

Calia secundiflora (Ortega) Yakovlev comprises trees from the Leguminosae family; it is widely distributed in Mexico. This species has been considered toxic for its high content of chinolizidine alkaloids, which are mostly located in seeds and leaves. The plant grows in disturbed zones, in soils with low content of organic matter, nitrogen and phosphorous and in wide open spaces, which is associated to the ecological role of the alkaloids. The objective of the present study consisted of evaluating the phytotoxic activity of aqueous extracts from leaves and roots of C. secundiflora on the germination and development of seedlings from seeds of Lactuca sativa, Amaranthus hybridus, Lolium perenne, Ipomoea purpurea and Bidens odorata. Different leaf and root concentrations of aqueous extracts were moderately phytotoxic by inhibiting germination and seedling growth; leaf extracts had higher phytotoxicity than root extracts.

Prolonging the vase life of ornamental species is important for their commercialization and for the consumer. We determined the effect of adding 0.05 % of CaCl2 to the preserving solution on the vase life of two cultivars of gerbera and their relationship with the antioxidant activity of CAT, APX and POX. The addition of 0.05 % of CaCl2 to the preserving solution significantly increased the average vase life of gerbera, four days in the cv. Duela and eight days in the cv. Shirlene. Calcium delayed the bending of the neck. The turgency and rigidity of the neck was attributed to the role of calcium in closing stomae, membrane stability and increase in the rigidity of the cell wall and the middle lamella. The protecting role of CaCl2 during neck senescence was related with high and continuous levels of the antioxidant activity of peroxidases (POX) and with a decrease, followed by an increase, of the activity of ascorbate peroxidase (APX) in the second half of the vase life for Duela and Shirlene. CAT activity in the presence of calcium seems to be regulated a differently than APX and POX.

La actividad antifúngica de extracto de resina hidrosoluble de gobernadora [Larrea tridentata (D.C.) Coville] (L) y soluciones de quitosán (Ch), solos y combinados fueron investigados in vitro por su actividad antifúngica contra Botrytis cinerea, Colletotrichum coccodes y Fusarium oxysporum f. sp. lycopersici que fueron aislados de rosas de invernadero y de lotes comerciales de papa y tomate respectivamente, mismos que posteriormente fueron purificados. Ambos bioproductos manifestaron su efecto funguicida a 1,000 y 2,000 ìl·litro-1, sin embargo, cuando fueron combinados mostraron una actividad fungicida sinérgica. Estos resultados preliminares indican que el extracto hidrosoluble de L. tridentata o la combinación L-Ch pudiesen ser considerados como agroquímicos potenciales de bajo impacto ambiental para ser usados como fungicidas orgánicos, pero se requiere más trabajo de investigación antes de que esto tenga una aplicación comercial. Hasta lo mejor de nuestro conocimiento esta es la primera vez que se reporta a la mezcla L. tridentata y quitosán actuando como un compuesto antifúngico.

“Caimito” fruit tree is a native specie from “Antillas” islands well adapted to the tropical regions of Mexico. Because all materials under explotation have not been grafted, there is a great genetic variability among them. In the region of Tetecala and Coatlán del Rio, at the Mexican State of Morelos caimito trees are quite common and they could represent a great potential to diversify the agriculture in the surrounding regions. In the present study, physical, chemical and morphological characteristics of fruits from 20 trees were evaluated. The measured traits were: fruit peel, pulp and seed weight, seed number, fruit length, fruit diameter and its ratio, pH, titrable acidity, total soluble sugars and color characteristics (luminosity, tone and chromaticity). A great variability was observed among the evaluated trees. The most representative variables for grouping were: fruit peel, pulp and seed weight, as well as, titrable acidity and total soluble sugars. The first group was formed by the largest materials (length: 59.5, diameter 59.1 mm) with highest weight (128.9 g), the largest seed number (3.3) and highest soluble solids content (11.7 ºBrix), this group also included the only green peel color fruit, as all the other materials had a dull red color. The second and third groups were formed by materials of lower weight (between 44 and 64 g) and size (40 to 45 mm in length and diameter), with intermediate and high values of soluble sugars (84 to 104 mg·g-1) and the lowest seed number (1.4 to 2.8). Therefore the materials of caimito from the first group have potential for selection and horticultural exploitation.

Frequently the mineral nutrition in husk tomato seedling production in Mexico is not practiced, or it is used in empiric way, without plan or not well executed, after that is translated in seedlings with low quality (heterogeneous, high and thin, early flowering, etc.) then they have establishment problems to the moment to be transplanted and they are not able to express its yield potential. The aim of this investigation was to determine the irrigation effect of the Universal nutritive solution Steiner in concentrations of 25, 50, 75 and 100 %, together with an additional treatment which the concentration in the solution was varied weekly (25, 50 and 75 %); as well as a solution of fertilizer Triple 18 ultrasoluble in concentration of 100 % and another where the concentration in the solution was varied weekly (25, 50 and 75 %) during the seedling development of husk tomato growing in containers under greenhouse conditions in Chapingo, Mexico. Three determinations on height, number of leaves, fresh and dry weight of seedling were carried out 15, 22 and 29 days after sowed (das), and one determination was made to the 29 das on stem diameter and nutrimental contained. The nutritive solutions affected the seedlings development to the 22 and 29 das. The content macronutrimental, except phosphorous, and micronutrimental, Fe, Mn and B, obtained with the nutritive solution Steiner to overcame the content obtained with the Triple 18 solution. The seedlings with better characteristics to transplant were obtained with the Steiner solution, in which was more convenient to use 50 % of the concentration or this solution whose concentration was varied weekly to save resources, nevertheless the Triple 18 solution can be a viable alternative.

In order to determine the appropriate suitable culture medium for mass microprapagation of in vitro Oxalis tuberosa Mol., apical and axillary buds were cultivated in the MS basic medium incorporating benciladenine (BA) 1.0 mg×liter-1 and 0, 0.1 and 1.0 mg·liter-1 naftalenacetic acid (ANA). The incubation conditions were 16 hours of photoperiod, 20 ºC of temperature and 90 mmol (quantum) m-2×s-1 of light intensity. The ratio 1:1 of growth regulators ANA:BA, promoted a rate of multiplication of nine shoots per explant cultivated. After 31 days vigorous shoots of three centimeters of lengh were observed. The basal callus production was developed in the explants after 56 days; they were not organogenic. The shoots were transferred to a root promoting medium MS with indolbutiric acid (AIB) 0.5 mg×liter-1. Rooting occurred after 15 days. The period to obtain new plants from the explants cultivated was 155 days.

The effect of honey bee, salicylic acetyl acid and molasses on movement and concentration of TSWV in tomato plants was evaluated. Inoculated plants were divided in seven segments (inoculated leaf, stem above of the inoculated leaf, leaf above of the inoculated leaf, apex, stem below of the inoculated leaf, leaf below of the inoculated leaf and root) and analyzed by DAS-ELISA at 15, 30 and 50 days after the inoculation (dai). Percent of positive plants to TSWV was similar in all treatments at 15 dai while at 30 and 50 dai, control treatment was different. Viral concentration evaluated at 15 and 30 dai was statistically similar in all treatments; at 50 dai, control treatment was different. In the three sampling dates, viral concentration in all treatments was similar in the different segments of the plant. Evaluated products reduced the concentration of TSWV at 50 dai but not affected the viral movement within plant.

In order to classify and order the fruit morphological variation of 31 cultivated variants of [Stenocereus pruinosus (Otto) Buxb.], identified by more than 20 informants from the Mixteca Baja region of Mexico, 19 morphological attributes were measured on 200 fruits (2-10 fruits per variant). Data were analyzed using means comparison, cluster and principal components analysis. Informants identified the variants by color, size and shape of fruits; size and color of spines; size and number of seeds; sweetness, flavor and production season. Although five attributes (peer thickness, number of areoles, thickness and width of seed; weight relation between flesh and peer) were statistically similar between variants, the multivariate analysis supports 16 for the characterization of variants. The first three principal components (CP) explained 60 % of the variation and ordered the variants by size and weight of fruit and size of seed and spine (CP1), color of flesh and peer (CP2), and fruit roundness (CP3). A consistent classification with these analysis defines nine groups, one of which is a putative interspecific hybrid. The traditional classification is confirmed by statistical analysis.