Indirect selection was performed on 100 maternal half-sib families of husk tomato based on early identification characters. The aim was to identify families with higher performance based on two or more early expression traits and high yield, under the assumption that their high genetic correlation will allow appropriate selection of superior families. At 40 days after transplanting, first bifurcation height (FBH) and fruit set number (FSN) were recorded. At 76 days after transplanting, yield (YP) and fruit number per plant (FP) were also recorded. Analysis of variance showed significant differences in FBH and FSN. Selection of the upper 10 % of families using the four traits separately was difficult. Cluster analysis formed four sets of families, whose characteristics were corroborated by discriminant analysis. This description enabled selecting the best families, which showed low FBH and FSN, and higher YP and FP. Early selection, supported by multivariate analysis, allowed selecting family groups with similar characteristics and identifying superior families.

This work was carried out in orchards of Mexican lime [Citrus aurantifolia (Christm) Swingle] affected by Huanglongbing (HLB) disease and located in the state of Colima, Mexico. The objectives of this work were to characterize the symptoms of the disease in the trees, to evaluate the effect of HLB on the yield and other physical characteristics of the fruit, to determine its dispersion within an orchard andquantify the total orchards affected by HLB. Results showed that in this citrus species, the new vegetative shoots grow strong and healthy looking despite having emerged from symptomatic branches. The symptoms start as small yellowish spots on the leaves when the shoots are 45 to 60 days old. And they show the asymmetric diffuse mottling characteristic of HLB disease when they are 60 to 70 days old. This damage was observed in trees located inside of a structure covered with anti-aphid mesh and also in unprotected trees in the field. There was a significant yield reduction proportional to the percentage of canopy affected by the disease. In HLB symptomatic branches of diseased trees, the fruit was smaller but no misshapen fruits, inverted ripeness or an increase in the number of aborted seeds were detected. In an orchard without HLB vector control, the disease was detected in 53 % of the trees in only one year. HLB is widely spread throughout Colima state. This is the first report on HLB disease symptoms in Mexican lime and their effects on yield and fruit quality.

An uncertainty analysis for a crop growth model allows to quantitatively evaluate the variability of the model’s parameters by deducing an uncertainty distribution for the model’s predicted variables. These studies only rarely have been applied to greenhouse crop growth models. In the present work a methodology to carry out an uncertainty analysis for a greenhouse crop model is described and it is applied to determine the variability of the NICOLET model parameters, which is a model developed to account for the growth of a greenhouse lettuce (Lactuca sativa L.) crop. Firstly, probability density functions were defined for all model parameters. Next, parameter values were chosen using Monte Carlo sampling. Both random and Latin Hypercube sampling and N = 2000 samples were used. Subsequently, 2000computer simulations were performed in order to calculate the outputs of the NICOLET model for each scenario. Finally, an analysis of the distribution of the variables carbon in the vacuoles, carbon in the structure, total dry weight and nitrate concentration was carried out, by calculating their histograms and statistic measures. For all the simulations the software package for uncertainty and sensitivity analysis Simlab was used, which is available for the programming environment Matlab. The results showed that carbon in the vacuoles has the greater uncertainty given that its coefficient of variation (CV) for both random and Latin hypercube sampling was 35.27 and 35.67 %, respectively, then the nitrate content (CV = 18.16 % and CV = 19.07 %), the carbon in the structure (CV = 5.52 % and CV = 5.67 %) and the total dry weight (CV = 4.80 % and CV = 4.82 %).

Chrysanthemum (Dendranthema x grandiflorum Ramat.) is one of the most important flowers grown in the world. Fungal diseases are the largest cause of economic losses during the production of this ornamental under greenhouse and field conditions. The aims of this study were: to identify the causal agent of chrysanthemum stem rot and to evaluate the response to infection of six chrysanthemum cultivars produced in greenhouses in Texcoco, State of Mexico. The causal agent of this disease was identified as Fusarium solani Appel & Wollenweber.(Teleomorph: Haemanectria haematococca Samuels & Nirenberg.) based on morphological, molecular and pathogenic characterization. In order to evaluate the response of chrysanthemum cultivars to infection by F. solani, plantlets were inoculated with a conidial suspension of 1 x 106 spores·ml-1. Disease severity was assessed on a 0-6 scale at 15 days after inoculation. The results indicated that allsix tested cultivars were susceptible to infection. ‘Polar’, ‘Eleonora’, ‘Indianapolis’ and ‘Quail’ were the most susceptible cultivars, whereas ‘Puma’ and ‘Spider’ were relatively tolerant.

The objective of the present study was to determine the rootstocks among a group of 20 that confer equal or better quality to the fruit of ‘Valencia’ orange with respect to that achieved with sour orange. The rootstocks evaluated were Troyer, Carrizo, Swingle, Sour orange (regional control), Cleopatra, Morton, Rubidoux, Rough Lemon, C-35, Sunki, Volkameriana, Macrophylla, Amblicarpa, Yuma, Taiwanica, Pomeroy, Shekwasha, Flying Dragon, Severinia buxifolia and Sacaton. The response variables were fruit size, skin color, roughness and thickness of skin, weight of the fruit parts (juice, skin, pulp, seeds) and internal quality. There were differences among rootstocks in equatorial and polar diameter, percentage of skin color of the fruit rind and weight of the fruit, seeds and skin, as well as degrees Brix, soluble solids and acidity. The rootstocks that matched the quality of fruit produced with Sour orange were: Flying Dragon, Cleopatra, Sacaton, Yuma, Morton, Rubidoux and Troyer.

Nowadays in Mexico, the yield of faba bean (Vicia faba L.) seed is low (0.7 t·ha-1). One reason is the use of landraces, and since it is a seasonal crop, production is further limited by the amount and distribution of rainfall. Thus, it is important to look for cultivars with greater water use efficiency (WUE) and therefore higher production. The aim of the present study was to evaluate WUE and yield of green pod and dry grain of 14 cultivars of faba bean (13 introduced and one native). Seed sowing occurred on March 30, 2006 at a density of 4.2 plants·m-2 in Serdán, Puebla under seasonal rainfall conditions. The fertilizer was 132-33-00 of NPK. All P and 50 % of nitrogen was applied before sowing and the rest 60 days later. The cultivars of early physiological maturity (PM) were ‘Tarragona 1’ and ‘Cochinera Montecillo’ (190days after sowing (das) and 3,023 growth degree days) and the later was ‘Cochinera Morada’ (225 das and 3,450 growth degree days). The greatest pod size was found in ‘Pico de Orizaba’ with 8.8 cm length and 23.4 mm width. ‘Cochinera Morada’ had the highest yield (1,037 g·m-2) and number of pod per m2 (113.1). The lowest yield was shown in ‘Cochinera Montecillo’ (456.1 g·m-2). The highest grain yield was found in ‘Blanca’ (357 g·m-2). In both cases yield was related to water use efficiency and harvest index. The native cultivar showed lower yield than some introduced cultivars. In general, the late cultivars showed higher biomass, yield and accumulated heat.

The objective of the present study was to make the morphological characterization of 47 accessions of roselle (Hibiscus sabdariffa L.) from the state of Guerrero, Mexico. The morphological evaluation included 50 characters which were separated in 40 quantitative and 10 qualitative. From these variables, 25 quantitative and five qualitative characters with high variability (P ≤ 0.04) were selected. Data were analyzed by means of correlations, regressions, discriminating analysis of groups and correspondence. With six quantitative and five qualitative characteristics it was possible to make the distinction and morphological grouping of the genotypes in four groups. The quantitative characters that contributed the most to the differentiation of the genotypes were length at the base of the main lobe of the leaf, fruit length, fruit perimeter, vertical length of the leaf, angle of the left lobe of the leaf, chroma (C) of the flower and color of the leaf quantified with a colorimeter (L). The qualitative characters that had the most influence were those associated with leaf color, earliness, stem color, color of bracts and the presence or absence of melliferous glands.

The aim of the present study was to identify commercial hybrids with genetic value to produce high yield hybrids or varieties because commercial hybrids can be used with success in breeding programs. A total of eight commercial hybrids of squash (Cucurbita pepo L.) type Grey Zucchini and their 56 possible crosses were evaluated at Chapingo, Mexico during 2007 and 2008. Heterosis (average, varietal, specific) was estimated using the model II of Gardner and Eberhart (1966) and with respect to the best parent. Results showed positive average heterosis for all the characters (YH: 1.10 t·ha-1; YPP: 13.10 g·plant-1; FRW: 0.10 cm; FRL: 0.50 cm; DFF: 3 days and DMF: 3 days) studied. The hybrid ‘Terminator’ showed favorable positive effects of varietal heterosis for yield and components (RPH: 3.62 t·ha-1; YPP: 63.37 g·plant-1; FPP: 0.73 fruits, FRL: 0.33 CM, FRW: 0.20 CM, DFF: 1.66 days and DMF: 1.67 days). The best parents for yield were ‘Terminator’ and ‘Lolita’ because they showed greater varietal heterosis. The best crosses among hybrids were ‘Grey Zucchini M+M’ x ‘Terminator’ (3x7) (Sij 3.78**), ‘Hurakan’ x ‘Lolita’ (5x4) (Sij 3.86**) and ‘Tala’ x ‘Terminator’ (1x7) (Sij 3.25**), which could be used in a breeding program to exploit the dominance effects by means of cyclic hybridization. The earliest three crosses, with 44 days to feminine flowering, were: ‘Lolita’ x ‘Tala’ (4x1), ‘WA9041’ x ‘Tala’ (6x1), ‘Dolarzini’ x ‘Tala’ (8x1) and the latest was ‘Terminator’ x ‘Hurakan’ (7X5)(54 days).

The transpiration rate (E) of ‘Colinmex’ avocado was evaluated over a year to determine its seasonal variation under two soil moisture (SM) regimes and its relationship to phenological phases. The following cultivar/interstock/rootstock (regional criollo originated from seed) and soil moisture regime combinations were evaluated: T1) ‘Colinmex’/’Colin-V101’/rootstock, irrigated; T2) ‘Colinmex’/’Colin-V101’/rootstock, rainfed; T3) ‘Colinmex’/’Colin-V33’/rootstock, irrigated; T4) ‘Colinmex’/’Colín-V33’/rootstock, rainfed. The transpiration rate varied from 1.38 to 4.55 mmol H2O·m-2·s-1 over the year; and during this time, available SM and ambient relative humidity (RH) were strongly correlated to E (r2 = 0.70 and 0.93, respectively). In the winter, T1 and T2 showed the highest E values, 3.32 and 3.3.18 mmol H2O·m-2·s-1, respectively. In the spring, E was similar from treatment to treatment with values ranging between 1.22 to 1.72 mmol H2O·m-2·s-1; this season also had the most severe SM deficit, the highest temperatures and the lowest RH. The highest E values occurred in the summer with averages from 4.45 to 4.65 mmol H2O·m-2·s-1. Similar E values were recorded during the fall for T1, T2 and T4 (4.10 to 4.90 mmol H2O·m-2·s-1). The highest averages of fruit weight, fruit number and fruit yield per tree corresponded to T3. Treatments with irrigation had the highest fruit production per tree.

The cowpea is an important human food crop, eaten as grain and green pods. The species has determinate and indeterminate growth cultivars. The latter require a conventional trellis, which increases production costs and thus creates the need for cheaper alternatives. The aim of the study was to determine, in different types of trellises, green pod growth and yield and cowpea profitability. Planting took place on June 8, 2009 in Cocula, Guerrero. The following were evaluated: time of occurrence of the phenological phases, green pod yield (GPY), pod number (PN), pod length and diameter (PL and PD), number of green leaves (NGL), leaf area index (LAI), leaf area duration (LAD), water use efficiency (WUE), evapotranspiration (ETc) and economic profitability in conventional, maize and sunflower trellises (CT, MT and ST, respectively). During the crop cycle, the average maximum temperature was 38 °C and the minimum was 20 °C, with 738 mm of precipitation. CT presented the highest GPY (1,501 g·m-2), PN (149 m-2) and WUE (5.4 g·m-2·mm-1), which was associated with greater NGL (334 m-2), LAI (1.3) and LAD (57 days). MT achieved the highest net income ($ 28,784.00), followed by MT and ST. Green pod productionat the site was achieved with 278 mm of crop evapotranspiration and 1,770 °C of heat units accumulated from planting to final cut.