Research was carried out with the objetive of study the effects of date and rate of iron quelate fertilization on growth, mineral nutriment composition and the correction of Fe chlorosis in four year peach trees established in a cley-loam soil. Four treatments of Sequestrene 138Fe per tree were tested:. 0, 120, 240 360g. Sequestrene 138Fe at 40 cm radius of the trunk at early and late spring during the year, were applied to trees. Content nutrients of Fe, Mn, P and Ca in the leaves were determinated and the intensity green colour in the foliage was evaluated too, and the shoot growth was register. Sequestrene 138Fe 360g treatment alleviated the chlorosis increasing the iron levels in the foliage four week after the second application. Sequestrene 138Fe did not increase leaf Mn and Ca content showing highest levels the check treatment. P foliar content no differents were found among treatments. With respect to shoot growth all treatments had not effect.

This investigation was undertaken with the objetive to preserve seed genetic purity and physiologic quality of four bean varieties. Variety characterization, and seed quality analysis were used to know crop performance under the environmental condition of La Laguna Region, Coahuila, Mexico. This research was carried in the spring of 1994. The materials were Lagunero 87 bean variety (from La Laguna region) Azufrado Peruano 87, Azufrado Regional and Azufrado Pimono 78 (from Los Mochis, Sinaloa). The evaluations were of quantitative nature: plant height, number of branches, petiole size, number of pods, kernel weight per plant, number of node per till. Laboratory analyses included germination and vigor test, number of normal plants, number of abnormal plants and number of dead plants. Field variables such as plant height, number of branches, number of pods number of nodes and kernel weight were highly significant differences among varieties. There was not significant differences among varieties for petiole size. Estimation of germination and vigor had a significant correlation with pod, branch and nod with the Lagunero 87 bean variety being outstanding followed by Peruano 87, Azufrado Regional and Pimono 78. The varieties from Los Mochis, Sinaloa did not have a significant response to La Laguna conditions for production of improved seed.

The infective forms of entomophatogen fungi are both espores and conids. One of the impediments for they use as biological controllers of plant diseases or plagues, from a commercial stand point, resides in the dificulty to obtain media culture formulations at low costs. In addition, these formulations must have the ability to produce espores with long viability, high pathogenicity as well as a long survival period once dryed and stored. The objective of this study was to evaluate the formulation of low cost culture media to produce both increased fungus dry weight as well as high concentrations of espores. The culture media formulated had as common components to Minimum essential media (MEM), and soybean meal (SBM), and as differential components to 1). Chitine (Q); 2). sea-shell (CB), and 3). shrimp cuticle (CC). Four different concentrations of these last components were evaluated in each media. The experimental design included an arrangement of treatments in a 3x4 factorial fashion. Effects of using different concentrations of the last component in the dry weight and blastospore number of the three fungal specie were evaluated by ANOVA in a completely random design. Dry weight was affected (P

Flies are important pest in cattle feedlots due to the milk production losses they cause and their action as vectors of disesse pathogenic agents. Biological control is an alternative to control stable flies at a low cost. There are different biological control agents of flies, such as parasitoids, which interrumpt the life cycle of flies attacking the pupae stage. Samples of menure containing fly pupae were collected weekly. Samples were taken to the laboratory to determine parasitoid emergence. The following genera of parasitoids were determined: Spalangia sp. and Muscidifurax sp., which caused 70 and 90% parasitism of fly pupae, respectively. Parasitoids were mass reared succesfully in the laboratory. House fly pupae were reared in the laboratory and then they were exposed to the parasitoid collected in cattle feedlots. With respect to the level of parasitism evaluated at different exposure time and host (fly pupae) density, it was higher when fly pupae were exposed to the parasitoid action for a period of time of 48 hours. A this time parasitoids parasitized 10 fly pupae.

Mesquite is an important arid land natural cattle fedd and frewood resource. However, its seed presents a testa or an impervious endocars, resulting in germination problems. Research was conducted to evaluate 25 pregerminative seed treatments by physical, chemical and thermic methods. In this study, based on comparation grouping of means by tukey, 9 treatments showed the highest germination percentages: 100 per cent sulfuric acid inmersion for 10 minutes; blender with blades and water for 10 seconds scarification; blender with blades and water for 10 seconds plus gibberellin inmersion at 1000 ppm for 6 hours; scarification with blender, its blader covered with masking tape for 2 seconds plus thiourea inmersion at 1% for 20 hours; masking tape covered blender blades scarification for 2 seconds plus soaking in potassium nitrate at 1% for 15 hours; masking tape covered blender blades scarification for 2 seconds plus running water immersion for 72 hours, changing water every 24 hours; hot water immersion at 85°C for 5 minutes plus cold water at 3°C for 5 minutes; hot water immersion at 85°C for 5 minutes. With values of 100; 97.50; 96.25; 93.75; 87.50; 83.75; 82.50; 78.75; and 71.25 per cent, respectively. Out of the nine tratments found promising, 100 per cent sulfuric acid immersion for 10 minutes; and blender with blades and water for 10 seconds scarification were the best for showing a high germination percentage, aside from being practical and economic to perform.

Pathogenicity of Rhizoctonia solani, Fusarium solani and Macrophomina phaseolina was evaluated using two bean cultivars (Pinto Americano y Pinto Laguna 87) and two soil humedity contents (Soil capacity and 60% of SC consumpted) under greenhouse at Comarca Lagunera, México. A randomized complete designe was used with 4 replications. Bean preemergent death was not different either bean cultivar, soil humedity content, or inoculated fungus. Postemergent death was higher in Pinto Laguna 87 (41 %) the Pinto Americano (28%) M. phaseolina was the most pathogenic fungus producing 68% of postemergent death (PD), which was similar inoculating this fungus associated to Rhizoctonia and/or Fusarium, it damaging in 59, 56 and 50% of PD in the associations M. phaseolina-R. solani, M. phaseolina-F. solani, M. phaseolina-R. solani-F. solani, respectively. Fusarium was not a pathogenic fungus, which associated to R. Solani and antagonistic effect could be involved.

The objetive of this survey, wich proved eight tratments as a result of the combination of two levels of water suministration (it based 70 and 55%, of evaporation) two levels of plastic covering pepper planted in flat and furrow. Pepper irrigated with 55% of the plastic covering evaporation, planted in flat was the better treatment (54.7 ton/ha) and the best water productivity was in flat with the plastic covering to 55% of evaporation (6.6 ton/ha/m3 of water). In addition the best treatment, using the economic indication, was the plastic covering in flat to 55% andto 70% of evaporation, respectively.

The research was at CENID-RASPA Experimental Center Gómez Palacio, Durango, from to April to August 1998. The objetive was to evaluate Reticulatus Melon production, using two different cultivation tecniques (mulching and non-mulching) and two different levels of irrigation. The hybrid evaluated was " Caravell" in four treatments with the combination of two cultivation techniques and two evaporation levels, 50 and 55 % registered within the standard tank type "A". The best results were obtained using mulch, having at a 55 % evaporation rate with a 67 cm irrigation level. This produced 64.2 ton/ha. The treatment wit the best evaporation of 50%, using mulch, produced a total of 46.8 ton/ha. The best treatment found not using mulch had a 67 cm irrigation level producing a total of 35.9 ton/ha. In conclusion, the best treatments were found having the highest evaporation rate using the mulching technique.

In beef production systems, the birth weight, weaning weight and yearling weight have a paramount importance both from an economic and biologic point of view. Because of that, prior to define any animal breeding strategy, it is required to evaluate the effect that some environmental factors may have on the phenotypic expression of such economic traits. This research evaluated the role that sire (T), cow (V), parity number (pn), sex of calf (s), calving month (cm), and year of birth (yb), exert on growth characteristics. Birth weight (BW, n=647), adjusted weaning weight at 205 days (WW, n=504), and adjusted weight at 365 days (YW, n= 258) from a Brangus herd from northwest Chihuahua (106 15’ O, 30 04’N) were analyzed by using General Linear Model techniques. Mean comparisons for simple effects were performed by Tukey test. Model I included all the independent variables who affected (P0.05); while the coefficient of determination (R2) was 0.88, the coefficient of variation (CV) was 12.9%. In Model II, WW was affected (P

Development of the National Beef Cattle industry strongly depends on the precision of selection of animals with a high breeding value for economic traits. Aim of this research was to evaluate the postweaning performance of four Beef Cattle breeds: Angus, Brangus, Simmental and Limousin. The study was conducted at the Calabazas Beef Cattle Center of the Regional Beef Cattle Association of North Durango located at the 103° 29' LW and 25° 32' LN. There were considered production records of 44 young sires which included live weights at three postweaning períods collected at 28 day intervals, the average daily gain among periods was also considered. Postweaning records were evaluated by Linear Model Techniques and included as independent variables to genotype, period as well as their interaction. The Angus breed displayed superiority (P