Considering that the characterization in plants like a set of characteristics to differentiation they taxonomicment, in the present research was established as objective the selection of reliable and discriminant morphological variables, by means of the analysis of variance, coefficient of variation, lineal correlation, stepwise selection analysis and principal components analysis. The characteristics election were from leaf, flower and fruit set of hawthorn (Crataegus spp.), of the collection of accessions established in the genebank of the Universidad Autónoma Chapingo. The statistical methods that contributed more in the selection of these morphologic characteristics and definition of descriptors were: the coefficient of variation, the principal components analysis and their analysis of correlation, in addition to the criterion of the researcher, obtaining 35 characters that contributed more in the morphologic characterization, of a total of 76 variables. The discriminant variables were: leaves of reproductive shoots: perimeter, length of the major and smaller axis, elongation index, feret diameter, compaction index, basal angle and number of veins; leaves of short vegetative shoots: perimeter, length of the major and smaller axis, elongation index, feret diameter, compaction index, apical and basal angle, number of veins; leaves of long vegetative shoots: perimeter, length of the major and smaller axis, elongation index, feret diameter, compaction index, apical and basal angle; stomata in reproductive leaves: stomata frequency and length of stomata; and of flower: pedicel length, length of the floral receptacle, perimeter and feret diameter of the petals, length of the style, perimeter, length of the major axis and feret diameter of anther filaments.

Three Mexican (CP-Roxana, CP-Paola and CP-J) and three USA (Aromas, Camarosa and Festival) strawberry cultivars were qualitatively compared in the Zamora-Jacona valley in Michoacán, México, in 2004-2005. Titrable acidity percentage (TA), total soluble solids concentration (TSS), firmness, color, size, shape, rates of weight loss during the post harvest period and sensorial characteristics were evaluated. CP-Paola fruits were the less acid during the first harvest months, with the highest SST/TA quotient, which is the most used parameter to determine consumer acceptability. CP-Roxana and CP-Paola yielded the reddest fruits but less firm at the beginning of the harvest period. CP-J produced a high percentage of deformed fruits.

The aim of the present work was to determine the commercial quality of roselle samples of Hibiscus sabdariffa L. from Sudan, China and México (Guerrero), as well as the antioxidant activity of the beverage prepared with them, in order to find out if there exists any differences among samples that could help to give a special place in the national market to the mexican Hibiscus sabdariffa L roselles. The variables evaluated include color of the roselles and their extracts, pH, acidity, and anthocyanin profiles. The beverages prepared with the roselles from China and México showed a deep-red color, while that from Sudan was brown-redness. The mexican roselles had the highest acidity and the lowest pH values, although China roselles presented the highest anthocyanin contents. The anthocyanin profiles obtained by HPLC of the roselles from the three countries were the same. According to the quality parameters evaluated, the roselles from México and China have better quality than that from Sudan. The roselle extracts from México had the highest antioxidant activity; this means that they possessed better nutraceutical properties than the extracts from China and Sudan, characteristic that could be useful to give an added value to mexican Hibiscus sabdariffa L. roselles.

In order to improve quality and plant production in poinsettia cv. Supjibi Red by using organic fertilization with lower detrimental impact in the environment, this research was designed to assess the effect of foliar sprays of two effluents from vermicompost [one obtained in 2003 (1) and another in 2004 (2)] and the substrates 1) volcanic rock, 2) mix 1 (peat + vermiculite, 1:1 v/v), and 3) mix 2 (leaf mould + volcanic rock + peat + perlite, 3:1:0.75:0.75 v/v). Foliar sprays were aplied every 10 days at 0.05 %. Irrigation with complete nutrient solution was performed daily in plants grown in volcanic rock, twice weekly in plant grown in mix 1, and once weekly in plants grown in mix 2. Plants grown in volcanic rock and sprayed with effluent 1 showed highest plant height (50.2 cm), chyatia number (64), area of bracts (3884 cm2), total dry weight (39.6 g), and leaf dry weight (13.6 g). There was no significant effect on number of shoots, number of flowers, specific leaf weight, anthocyanin concentration, and bract color. Effluents did not have significant effect in leaf nutrient concentration. Effectivity of effluents varied depending of substrate. The best treatment was volcanic rock plus foliar sprays of effluent 1, this treatment could be used to the hydroponic culture of poinsettia stock plants.

The postharvest characteristics and fruit quality of four banana cultivars for fresh consumption grown without chemical control of black sigatoka and submitted to ethylene application were evaluated. The banana cultivars were Grande Naine (AAA) and Williams (AAA), both susceptible to black sigatoka, as well as FHIA-23 (AAAA) and FHIA-17 (AAAA), both tolerant to such disease, which were grown under irrigation conditions in Nayarit, Mexico. At harvest, all the bunch and fruit characteristics were recorded. Immediately fruits were submitted to 100 μl·litro-1 ethylene for 16 h keeping a control. Then, fruit quality characteristics were recorded during the ripening process under market simulation (22 ± 2 ºC y 75 ± 10 % RH). Every three days peel color, pulp firmness, total soluble solids, tritatable acidity and starch content were assessed. It was found that Williams and FHIA-23 yielded heavier bunches than Grande Naine, however, Williams was more similar to Grande Naine in bunch and fruit characteristics while FHIA-23 showed the best postharvest quality. In addition, it was observed that Williams was the only cultivar which ripened suitable without exogenous ethylene while Grande Naine, FHIA-23 and FHIA-17 required it for optimum ripening. Finally, it was observed that the exogenous ethylene application accelerated too much the ripening process in Williams and FHIA-17, which caused a very short shelf life.

The husk tomato is a Solanaceous plant of Mexican origin. In Mexico, this plant can grows at wild or culture way. The in vitro propagation is an alternative for producing very much healthy plants. But some times the acclimatization has been the limiting factor to reach this objective. There are not so much reports related with husk tomato micropropagation, and this is the first where the changes on stomatal density and water potential, are evaluated. That evaluation was done during the acclimatization from plantlets obtained by mean of apical meristem culture. Plants of 30 days old with similar size were placed in individual hydroponics system, during seven weeks, all of them covered with plastic covers, which were opened each seven days. Each time, the temperature and relative humidity were measured, in the acclimatization system and the growth chamber, for calculating the water potential. At the sixth week, the water potential in the acclimatization system was close to that of the growth chamber (-107.8 and -102.2 ± 4.91 respectively). On the other hand, the stomatal density was evaluated at 15, 30 and 45 days during the acclimatization stage. Significant differences were observed at this parameter between adaxial and abaxial leaf plant and between plant ages. When both water potential and stomatal density data were related, a great correlation was observed. 100 % of the plants survived later the acclimatization stage.

Below normal zinc (Zn) foliar levels, as well as visual symptoms of Zn deficiency in leaves, shoots and fruit are commonly observed in ‘Hass’ avocado orchards in the municipalities of Tepic and Xalisco, Nayarit. The research was undertaken from 2001 to 2005 in two commercial non-irrigated ‘Hass’ avocado orchards in the municipality of Tepic. The objective was to assess the effect of foliar or soil zinc sulphate (ZnSO4) applications on Zn foliar levels, as well as on yield, fruit size and fruit form. Orchard soil was of light texture, pH 5.8 and low Zn content (1.4 to 3.13 mg·kg-1). Tree canopy sprays treatments were applied using 8 L water·tree-1 and were: a) a single spray of 4,056 g ZnSO4·L water-1 (1.46 g Zn), and b) two sprays of 2.028 g ZnSO4·L water-1 (0.73 g Zn); both treatments delivered 11.68 g Zn/tree. Soil treatments were annual and consisted of: a) single application of 1.5 kg ZnSO4 (35.5 % Zn)·tree-1, and b) two applications of 0.75 kg ZnSO4·tree-1 each. Control trees were let untreated. ZnSO4 foliar sprays were ineffective to correct foliar Zn deficiency and had no positive effect on yield and fruit size. Two soil applications of 0.75 kg ZnSO4·tree-1year-1 were effective to increase yield, fruit size and fruit form (more elongated), decreasing the production of small and round fruit. This treatment also increased Zn levels in leaves and fruit pulp. A poor relationship between ZnSO4 soil rates tested and Zn leaf content was found.

The present experiment was carried out to evaluate the feasibility of using coconut coir dust as a growing medium for the germination and initial development of six ornamental plant species, and to determine the possibility to substitute Peat Moss. The species selected for the study were: Dianthus chinensis (Dianthus), Gazania rigens (Gazania), Tagetes erecta (Marigold), Viola wittrockiana (Pansy), Antirrhinum majus (Snapdragon), and Petunia x hybrida (Petunia). Seeds of the six species were germinated in coir dust, Peat Moss or Peat Lite. Previous seeding, the pH of coir dust was adjusted to 6.2 and it was amended with dolomitic limestone and KNO3 as nutrient charge. Afterwards, coir dust or Peat Moss was mixed with perlite and vermiculite at a 70:20:10 proportion (v/v), respectively. A randomized block design with three replications was selected to evaluate the effect of the growing media on plant height, shoot and root dry mass, germination rate and marketable ranking of plants. Shoot height of plants grown in coir dust was decreased significantly in gazania (21 %), snapdragons (30 %), and petunia (13 %), as well as shoot dry mass of snapdragons (24 %) and root dry mass of dianthus (22 %). Nonetheless, coir dust did not affect plug quality since the percent of marketable plugs and germination rate were comparable in coir dust and Peat Moss. It is concluded that coconut coir dust can be used as a growing medium in ornamental plug production and can substitute Peat Moss.

Concentration of harvest during the normal season affects mango commercialization in Nayarit, since it makes the prices drop. The objective was to evaluate the effect of gibberellins (AG3) on ‘Tommy Atkins’ and ‘Ataulfo’ vegetative growth and flowering. Two experiments were set, one in ‘Tommy Atkins’ and other in ‘Ataulfo’. Two dosages of gibberellins (25 and 50 mg·liter-1) were evaluated as well as five application dates (September 15, October 15, November 15, December 15 and January 15) considering a control without application. A completely randomized design with six replications was used. The main variables were vegetative growth and flowering. In ‘Tommy Atkins’, the earliest application (September 15) of 25 and 50 mg·liter-1 of AG3 inhibited normal flowering (63 and 76 %, respectively). In ‘Ataulfo’, both dosages inhibited up to 88.3 and 94 % normal flowering in all application dates, except for January application. The 50 mg·liter-1 (AG3) dosage was more severe in inhibiting flowering in both cultivars. However, the latest application (January 15) promoted flowering nine to 10 days in ‘Ataulfo’ and 12 in ‘Tommy Atkins’. In both cultivars, the shoots that were in vegetative or inactive growth, showed a delayed flowering from four to five weeks in ‘Tommy Atkins’ and six to nine in ‘Ataulfo’.

The genus Crataegus L. in Mexico is constituted by 13 species for the centre and north, and probably two for the south, out of these 9 to 10 species are endemic. The possible distribution of this genus in Mexico is unknown, but species of this genus have been reported in 20 of the 32 states of Mexico; however, species of this genus can be found in other entities of the country because of the weather where they grow. The present research has as an objective the establishment of the possible distribution of the genus Crataegus in Mexico by an analysis of Geographic Information System (GIS), and the identification of possible eco-climatic zones where species of the genus Crataegus are. The major distribution probability of the genus Crataegus in Mexico is in the mountainous zones of the Sierra Madre Oriental, Sierra Madre Occidental and the Sierra Madre del Sur, also in the Neo-Volcanic Axis. The groups of climatic distribution are three: the group 1 presents template climate (Neo-Volcanic Axis), the group 2 semi-desert to desert (North and Northeast of the country) and the group 3 subtropical climate (Mountains zones to South Pacific and Gulf of Mexico).

One of the substrates used to reproduce Trichoderma spp., it is the rice grain of, which has relatively high cost. With the purpose of finding an organic, economic and available substrate in the region, in the one which this fungus has a good development and a high production of viable spores, this investigation has as objectives to evaluate 15 organic substrates in the massive reproduction and viability of spores from T. harzianum, and to associate it with the nutrimental composition of the evaluated substrate. Husk tomato (flower calyx); rice (flower glumes, lemma and palea); garlic (coriaceous cataphyllary); cocoa (seed coat); sesame (fruit pericarp); peanut (fruit pericarp); coffee (fruit pericarp); bean sheath (fruit pericarp); corn cob (feminine inflorescence rachis); grains of rice, sorghum, bird seed and corn; soybean and corn stubble were evaluated. A randomized complete block design with eight replications design was used. It was quantified the number and viability percentage of the spores and it was correlated with the proximal chemical analysis. The corn cob is the best substrate as much in the production as in the spores germination of T. harzianum with 4.43 x 108 ml-1 and 99.0 % of viability. In base with the proximal chemical analysis, the mycelium development, esporulated and spores viability, T. harzianum has a good production in those organic substrates that have high humidity percentage, low content of minerals, protein and fat, and an intermediate fiber percentage.

This study was conducted with the purpose of learning the effects of prohexadione-calcium (P-Ca) in the levels of endogenous gibberellins in tomato saladette (Lycopersicon esculentum Mill.) and bell pepper (Capsicum annuum L.) shoot apex. Growth retardant was sprayed at three dosages (125, 175 and 200 mg·liter-1) in both vegetables crops when six true leaves appeared in seedlings. A control (H2O) was included in each crop species. Shoots apex was collected at 0, 1, 3 and 6 days after treatments, and were later lyophilized. Gas chromatography and mass spectrometry assays was used to determine quantity and quality of gibberellins. Results showed that tomato saladette apex sprayed with P-Ca reflected less gibberellins A4 and A7 from the first day on words after treatment. This tendency was similar in bell pepper samples. The GCMS analysis allowed to identify gibberellin A20 in tomato, and gibberellins A20 and A53 in bell pepper samples from P-Ca treated plants. The gibberellins A1, A4 and A7 were detected in control samples.

During the last decade there has been an increased demand for cyclamen as a potted ornamental plant in Mexico. It is needed to produce high quality seed at low cost. The objective in this work was to investigate if there is any influence of the age of the mother plants on phenology, seed production and quality. The cv. Lugano Supreme special mix was used and plants were grown in a plastic greenhouse were air temperature varied between 5.4 and 34.0 ºC, with an average of 17.8 ºC. The treatments were three plant ages: one (T1), two (T2) and three (T3) years respectly. The phenological stages considered were: PS1: when floral button had from 1.0 to 2.0 cm of diameter, PS2, floral button with 2.0 to 3.0 cm of length, and PS3, initial flower opening. T2 had the fastest development: time from PE1 to PE2 was of 30 days, statistically shorter than in the other treatments; from PE1 to PE3 was 38, statistically similar to T1 with 42 days, and from PE1 to harvest was of 120, statistically similar to T3 with 123 days. Regarding capsule setting, T1 was significantly superior (83 %) to T3 (66%) but similar to T2 (75 %). T3 and T2 had a seed yield (2.16 and 1.92 g plant-1, respectively) superior to that of T1 (1.02 g plant-1). Ratings for seed quality characteristics for all treatments were: % germination, lower than 60 %; viability, lower than 65 %, and weight of 1000 seeds lower than 6 g. All of them below standards required for certification process.

Studies with the ‘Green Goddess’ calla was carried out in a tropical highland area. 35 % shaded potted plants were grown with several types of vermicompost: coffee pulp; coffe pulp + bovine manure; coffee pulp + chicken manure + sugar cane straw. Other treatments were coffee pulp + chemical fertilizer (12(N)-11(P)-18(K)-3 mg) + Organozyma® (natural growth biostimulator). Leaf area, number of emerged shoots, and length of floral peduncle were significantly superior in the plants treated with vermicompost in comparison with those chemically treated with fertilizers and Organozyma®. Flower peduncles from those treated plants were harvested and put in glass flasks, and all treatments were statistically similar in postharvest longevity. In a different study, a harvest index for ‘Green Goddess’ calla was established. When the spathe was open enough to observe the spadix the postharvest longevity was of 37 days without any flower quality decrement. 1717 heat hours of 7 oC were determined since the plants had 15 cm of length until harvest. The maximum, minimum and average all day temperatures per month during the growth period of the crop were 21.1 °C (October), 7.8 °C (December) and 16.6 °C (November), respectively.

In the agronomic research, factorial experiments are frequently carried out. These are tools that make an optimus use of resources; produce more precise estimates of contrasts of treatment means, and make it possible the study of the interactions among factors. The full release of these advantages, however, is not always obtained due to one or several of the following common problems: Poor interpretation of the interaction concept; abuse of multiple comparison procedures; subutilization and even omission of regression techniques, orthogonal contrasts and polynomials, etc. To contribute to solve these problems and thereby to improve the quality of the scientific articles to be published, in this paper several meanings of the interaction concept, including since its etymological aspects until its meaning as a source of variation in the analysis of variance, were analyzed. In addition, cases related with the pertinence, use and advantages of regression, contrasts, and orthogonal contrast and polynomial techniques were analyzed in the context of factorial experiments. To make a more objective presentation, hypothetical cases of factorial experiments were considered. It is hoped that the reader’s conceptual perception and capacity to successfully associate cases of factorial experiments and statistical methods to analyze them properly will be improved and thereby will enable them to increase the quality of the interpretation of the results and their scientific publications.

This study was done with the aim of investigate on the root distribution of persian lime trees growing in a sandy soil and on a clay one in Martínez de la Torre, Ver. It was employed the soil trench profile method, and the roots were classified into four categories, according to their diameter: R1 (>15 mm), R2 (5-15 mm), R3 (1-5 mm) and R4 (<1 mm). The trenches were 4 m long, 1 m deep and 0.8m wide and three trenches were made for each tree (50 cm from the trunk, canopy perimeter and half-way between them). For each soil four homogeneous trees, twelve-years-old and nine-years-old for the sandy soil and for the clay one, respectively. The roots were grouped into three depth stratum (0-30 cm, 30-60 cm and 60-100 cm). The number of roots was submitted to an analysis of variance and to a multiple means comparition test, considering the depth and the distance from the trunk as factors. The higher number of roots was observed, for both types of soil, in the 0-30 cm deep soil stratus, decreasing in the deeper strata. The number of roots followed the tendency to decrease as the distance from the trunk increased. The most abundant roots were R4, or fibrous, followed by R3, R2 and R1.