In order to evaluate the usefulness of tomato hybrids as potential progenitors for a breeding program, two 5 x 5 diallel designs (Griffing II) were developed using two types of saladette tomato: determinate and indeterminate growth habits. For fruit weight per plant (FW), the determinate growth habit hybrid DG05 showed good specific combining ability (SCA) and high intervarietal heterosis (IH), while DG03 hybrid had high general combining ability (GCA); therefore, both hybrids have good potential for use as foundation parents in hybridization and selection breeding programs, respectively. For the saladette indeterminate growth habit type, IG01 and IG04 hybrids showed the highest GCA values in addition to good SCA between them for FW; therefore, they could be used for both selection and hybridization breeding programs.

The search for new natural herbicides was performed using studies of phytotoxic substances because they do not affect the environment and are less toxic than synthetics. In literature there is little evidence of phytotoxic effects of capsaicinoids, present in the genus Capsicum, thus the objective of this research was to evaluate in vitro the phytotoxic effects of the extracts of the manzano hot pepper (Capsicum pubescens R & P) fruit on germination and vigor of Amaranthus hybridus L., Lactuca sativa L., Ipomoea purpurea L. and Bidens odorata Cav. A germination test was performed according to the methodology of the International Seed Testing Association. The effect of six concentrations of extracts (0.5, 1.5, 2.5, 5.0, 10, 20 % v/v), capsaicin (0.1 w/v) and ABA (0.01 w/v) was evaluated in an experiment using a completely random design with four replications of 50 seeds each. The control was distilled water. The variables evaluated were: number of germinated seeds (NGS) and vigor (length of radicle, RL, length of the aerial part, LAP). Variance analysis and Tukey comparisons (P ≤ 0.05) were performed. The dichloromethane extract, compared to the ether extract, caused the most phytotoxic effect on the germination of A. hybridus and L. sativa, in which the percentage dropped to 100 %; it also negatively affected the vigor of I. purpurea. The phytotoxic effect of capsaicin on germination and vigor was only evident in A. hybridus.

The objectives of this work were to evaluate the effect of different seed densities on hydroponically-grown wheat and barley fodder yields, as well as the nutritional value of each hydroponic fodder obtained and its effect on weight gain in sheep. Three seed densities for two species were compared (4.7, 5.2 and 5.7 kg·m-2 for wheat, and 3.5, 3.9 and 4.3 kg·m-2 for barley). A randomized complete block design with 10 replications was used. The best density for wheat was 4.7 kg·m-2, with a yield of 30.2 kg·m-2 in fresh weight and a conversion ratio from seed weight to fresh fodder weight of 1:6.4. For barley the best density was 3.5 kg·m-2, with a yield of 32.8 kg·m-2 and a conversion ratio of 1:9.3. By increasing the density, both the dry matter content and the conversion ratio decreased. In another experiment, weight gain in Pelibuey sheep in three feeding systems was evaluated: hydroponic wheat fodder, concentrates (milled sorghum and soybean meal at a 4:1 ratio) and grazing feed supplemented with concentrate feed. A completely randomized design with four replications was used. A daily gain of 159 g in body weight was obtained with hydroponic fodder, against 136 g in the grazing system supplemented with concentrate feed, and 116 g with the concentrate diet alone. It is concluded that the use of hydroponically-grown wheat fodder is a technically and economically viable option for feeding Pelibuey sheep for fattening purposes.

The objective of the present research was to evaluate the CIELAB parameters of luminosity (L*), chromaticity (C*), and Hue (H°) angle, as well as tannins, total phenols and anthocyanin contents in wild population of Mexican serviceberry fruits at trees stages of maturity. Luminosity was reduced 51 % and 66 % in fruits collected in La Valenciana and El Derramadero, respectively, while chromaticity was reduced at similar levels than L* and Hue angle increased. Total soluble phenols were reduced from 763.0 and 834.5 mg·100 g-1 at the unripe stage from 497.5 and 538.5 mg·100 g-1 at the overripe stage. Condensed tannins were reduced as fruit ripened. Total anthocyanin increased from 10.08 and 14.7 mg·100 g-1 at the unripe stage from 16.57 and 17.72 mg·100 g-1 at the overripe stage. The content of phenolics and tannins in the Mexican serviceberry is from 10-20 % higher compared to many commonly consumed fruits. This fruit can be considered a fruit with nutraceutical properties.

In order to produce a document that identifies the morphological stages of floral differentiation in tomato, a microscopic study was conducted at Chapingo Autonomous University from October 2010 to October 2011. Two tomato varieties, Charleston and Barbarian, ball and salad types respectively, were planted to generate plant material. They were germinated in a special chamber and upon emitting cotyledons were taken to a glasshouse where they remained until having the second inflorescence. During this period, isolations, observations and photomicrographs were made of the meristems and floral organs. Based on these images and others reported by other authors, each of the morphological stages of the floral differentiation process were interpreted and described. It was observed in this species that vegetative to reproductive differentiation occurs in the apical meristem, and when the first inflorescence forms a vegetative axillary bud continues growth and retakes apical dominance. After forming three phytomers, the second inflorescence appears. The inflorescences form basipetally: i.e., when the meristem changes to reproductive it divides into two and two floral primordia appear, then on the base more primordia appear consecutively until the complete inflorescence is formed. The floral organs appear centripetally: first the calyx, then the corolla, later the androecium (filament and anthers) and finally the gynoecium (ovary, ovules, style and stigma).

Con el objetivo de conocer los requerimientos nutrimentales del cultivo de chile de agua, se determinó la absorción y la curva de extracción de N, P, K, Ca y Mg. Para ello la colecta denominada ‘Ocotlán’, proveniente del estado de Oaxaca, se estableció en un sistema hidropónico abierto con sustrato de espuma volcánica (tezontle rojo). Se empleó la solución nutritiva de Steiner bajo cinco potenciales osmóticos (0.018, 0.036, 0.054, 0.072 y 0.090 MPa). La unidad experimental fue una planta y el diseño experimental usado fue completamente al azar con tres repeticiones. Se determinó la acumulación de materia seca, el rendimiento de fruto y la extracción de N, P, K, Ca y Mg, y se aplicaron análisis de varianza y pruebas de comparación de medias. Mediante regresión se estimaron los parámetros de modelos no lineales, para realizar un análisis de crecimiento, los cuales determinaron que la presión osmótica de 0.054 fue la adecuada para obtener el mayor rendimiento del cultivo. La extracción nutrimental (g·planta-1) obtenida al final del ciclo de crecimiento fue 16.93, 1.12, 16.62, 3.54 y 1.27 de N, P, K, Ca y Mg, respectivamente. La cantidad de nutrimento para producir una tonelada de fruto fue 7.7, 0.5, 7.64, 1.6 y 0.6 kg de N, P, K, Ca y Mg, respectivamente. La máxima tasa de absorción de los nutrimentos se observó durante la fructificación.