Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

The objective of this study was to increase the productivity of maize in High Valleys of Mexico, at the Valley of México and Bajio Experimental Stations of the National Institute for Forestry, Agriculture and Livestock Research (INIFAP). The following activities were carried out: production of registered seed to strengthen seed micro- enterprises of national capital, quality evaluation of certified seed, and generation of production technology. Between 2005 and 2013, 46.71 tons of registered seed of the hybrids parents: H-40, H-48, H-50, H-52, H-66, H-70 and H-161, and the varieties: VS-22, V-54A and V-55A were produced and sold to 31 seed producers in the Estado de Mexico, Tlaxcala, Puebla, Hidalgo, Morelos, Guanajuato, Michoacan, and Jalisco; that satisfied 60 % of demand per year (8.68 t). In 2013 and 2014, agreements were signed between INIFAP and four micro-enterprises to produce registered seeds. The certified seed produced by companies reached certification standards, germination percentage ≥ 85, 98% pure seed and less than 2% inert matter; test weight between 72 and 78 kg/hl, thousand seed weight between 288 and 361 g and genetic quality between 96 and 98 % of the true type plants. The study identified information about locations, potential yields, population density, and planting dates for the production of parents, lines and single crosses, in the Estado de Mexico and Tlaxcala.

The objective of this work was to evaluate the yield and quality of oil from seven Ricinus communis varieties. The morphological properties (height of plant, productive branches, length of clusters), yield of seed, and oil quality. The evaluation was conducted at the Fabio Baudrit Moreno Experimental Station of the University of Costa Rica, Alajuela, Costa Rica, from September 2013 to April 2014. A randomized complete block design with a density of 5000 plants/ha was used for the evaluation. The varieties evaluated were ColBio RH 171,09, ColBio HR 205, ColBio HR 268, ColBioHR 157, 401, and NIC. The parameters evaluated showed significant difference (a<0.05). The seven varieties constituted all medium-sized plants. The average was four productive branches for all varieties. ColBio HR 268, ColBio HR 205, and ColBio HR 171 obtained the longer cluster. Stem diameter showed an average between 3 and 4 cm for the seven treatments. In relation toseed yield, variety NIC had the lowest value (860 kg/ha), while ColBio HR 171, 09, ColBio HR 205, and 268 had the highest yield with an average of 2377kg/ha. Oil content was higher for treatments 401 (88%) and ColBio HR 171 (87%). The array 09 showed the highest content of ricinoleic acid (80%), followed by ColBio HR 268 (69%) placing both also among the varieties with higer seed yield, but with lower oil content.

The objective of the present study was to determine the effect of the salts concentration described by Murashige and Skoog (MS) in short term in vitro conservation of nodal segments of Spanish Carnation (Dianthus caryophyllus L.). The investigation was developed in the Center of Vegetable Biotechnology Studies (CEBV), in the period 2012- 2013. The treatments consisted on the addition of MS salts (100; 75; 50; 25%) and a control (100% + growing regulators) in medium culture. Decreasing until 25% of salts concentration in culture medium reduced the growing speed, being able to conserve for six months under these conditions A survival and recovery of 91,3% was obtained.

The aim of this study was to determine the yield variation patterns in orchard grass (Dactylis glomerata L.) under grazing management. This study was performed in Montecillo, Texcoco state, Mexico from June 2005 to July 2006. Three grazing frequencies (21, 28 and 35 days) and two grazing intensities (5-7 and 9-11 cm residual sward high) were evaluated in a completely random block design with three replicates. The variables grass yield, seasonal distribution, growth rate, botanical and morphological composition and tiller population density were all evaluated. A 35 day-grazing frequency produced the highest yield (P<0.05). Independently of the grazing intensity and its frequency the seasonal yield was: 49.5, 31.6, 14.1 and 4.8% for spring, summer, winter and fall, respectively. The highest growth rate was registered during spring when grazing occurred every 35 days, and the lowest during autumn when grazing occurred every 28 days (P<0.01). During winter grazing only occurred every 21 days, and this may have led to 60% contribution to total yield by other species. Results also suggest that tiller density was not affected by grazing intensity and frequency on tiller population density.

The objective of this work was to quantify technical efficiency in 1086 dairy farms from Costa Rica (year 2007) using Stochastic Frontier Analysis. The base model analyzed the endogenous variable logarithm of Milk Solids (kg/ha/week) as a function of 14 different predictive variables related to physical and management aspects. Overall mean for milk solids was 32.5±23.5 kg, with the highest mean for typology of Specialized Intensive Dairy Herds from the Highlands (83.9 kg), followed by Intensive Dairy Herds from the Lowlands (51.0 kg), Semi-Intensive Dairy Herds from the Highlands (33.8 kg), Extensive Dairy Herds from the Lowlands (23.0 kg) and Dual Purpose Herds from the Lowlands (8.5 kg). Variables associated (P<0,001) to milk solids were stocking rate, fertilizer application, concentrate feeding, proportion of cattle from specialized dairy breed, altitude and grazing area. An increase of 1% in these variables was associated with a change of 0,85%, 0,07%, 0,07%, 0,19%, 0,15% and -0,10% in milk solids, respectively. Overall technical efficiency was 0,75±0,09. When farm typology was added as a predictor into the model, efficiency increased to 0,79±0,07, whereas adjusting the model separately for each farm typology resulted in an overall efficiency of 0,77±0,11. The latter was preferred because better reflects heterogeneous elasticity of predictive variables between different typologies.

The objective of this study was to determine the concentration of total immunoglobulins (Ig) in colostrum produced by dairy cows and establish the effect that breed and parity can have on Ig concentration. The data presented correspond to determinations of concentration of total Ig determined by a colostrometer in 537 colostrum samples obtained between the year 2010 and 2012, during the months of August to November in 50 dairy farms in the provinces of San José, Alajuela, Heredia and Cartago. Cow breeds were classified into Holstein, Jersey, HolsteinxJersey and other. Farm size ranged from 10 to 300 milking cows. For the purposes of this study, good quality colostrum was considered when Ig concentration was ≥ 50 mg/ml. Immunoglobulin concentration ranged from 10 to 140 with an average of 85 mg/ml. Of all the samples analyzed, 13.2% had an inadequate concentration of Ig. When considering breed effect on Ig concentration, no significant differences were found. Parity number significantly influenced Ig concentration and it was found that Ig concentration increases linearly with parity number. The information collected in this study indicates that Ig concentration in colostrum is good and that failure of passive transfer of immunity could be due to other factors such as the volume of colostrum consumed and the time between birth and the first feeding of colostrum.

The objective of this study was to evaluate the productivity of non-conventional intervarietal maize hybrids with yellow endosperm grain with respect to their parental varieties. At the National Institute for Forestry, Agricultural and livestock Research (INIFAP) and the Faculty of Superior Studios Cuautitlán, of the National Autonomous University of Mexico (FESC-UNAM), early maize varieties of yellow grain were generated. In the year 2010, combinations with two single crosses were carried out. In 2012, 15 genotypes were evaluated in three uniform experiments, with three repetitions. Two trials were planted in the FESC-UNAM, and the other one in the Experimental Station of Valley of Mexico. The combined analysis detected differences highly significant to the variable performance in genotypes, environments and the interaction genotype x environment. The best non-conventional combination of single cross x variety, CS156 x V 54 A (6,796 kg/ha), yielded 38% more than V-54 A (4918 kg/ha) and the second best combination (CS156 x V 55), yielded 6,204 kg / ha, which was superior by 17.3% compared to its progenitor variety V-55 A (5,288 kg/ha). The grain yield was increased by crossing the improved varieties with the single crosses. This represents an alternative to offer genotypes with greater productive capacity while maintaining its same maturity and with ease for the supply of maize seed for the farmers.

The objective of this study was to evaluate the response to natural infection of Fusarium spp. on 55 native maize populations. The populations evaluated were collected in five states of Mexico, and planted in three locations in 2010 and 2011 under rainfed conditions. The average percentage of ear rot was significantly different among maize populations, locations and among populations within locations and years. The population groups of kernel color showed differences among them, where yellow and red groups presented the lower infection percentages. In the relation to geographic provenance, maize populations of Oaxaca presented less damage than those from Mexico, Puebla, Tlaxcala and Guerrero states. In grain yield, there were differences among locations, populations and years. In the significant interaction between population groups and locations showed that populations with local origin presented low ear rot percentage and major yield, which suggest a coevolution and coadaptation process. The higher ear weight was obtained in 2011, where the Oaxaca populations were outstanding. It is possible to infer that native maize populations from Oaxaca are a potential source of resistance or tolerance to ear rot caused by Fusarium spp.

The objective of the present study was to determine the milk yield of Simmental-Zebu and Brown Swiss-Zebu cows with different proportions of Bos taurus genes. The study was carried out from 1985 to 2007 at the the Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias, Playa Vicente research station (Veracruz, Mexico). The site presents a humid tropical climate. Milk yield records of Simmental × Zebu and Brown Swiss × Zebu cows with different proportions of Bos taurus genes (50, 62.5 or 75%) were analyzed. The cows were maintained in rotational grazing of the introduced pastures: Star grass (Cynodon plectostachyus) and Guinea (Panicum maximum), and were milked twice a day, after a restricted suckling by their calves. Calves were weaned at 210 days of age. The statistical model included the fixed effects of breed group, year of calving, season of calving, lactation number, and lactation length as a linear covariate; in addition, the model included sire of the cow within breed group as a random effect. The lactation length of Brown Swiss × Zebu cows was greater (P<0.05) than that of Simmental × Zebu cows. Milk yield per lactation, per day and per calving interval of Simmental × Zebu and Brown Swiss × Zebu cows were similar. Third-parity cows yielded more milk (P<0.001) per lactation, per day and per calving interval than first- and second-parity cows. Second-parity cows yielded more milk (P<0.001) per lactation, per day and per calving interval than first-parity cows.

The objective of this investigation was to study greenhouse precocious spears yield of three genotypes of asparagus on its fifth harvest season. The trial was established at the Faculty of Agricultural, Pontifical Catholic University of Argentina, on November, 15, 2006. 19 different harvests were made from 04/09/2012 to 22/10/2012, one every two days. A multifactor ANOVA-LSD test (P>0.05) was performed. Variables analyzed were: total productivity and commercial productivity (PFT and PFC), total number of spears and commercial number of spears (NTT and NTC); caliber distribution (DC): Jumbo (J), Extra-Large (XL), Large (L), Medium (M) and Small (S) and finally, quality defects (D): spiked spears (TE); short spears (TC) and other defects (OD). During the post-harvest period, bundles (A), trays (BA) and polyethylene bags were used to study fresh weight evolution (EPF); daily fresh weight loss (PPFD) and average fresh weight during the post-harvest period (PPFP). Italian breeds yielded above 9 t/ha, twice the Argentinean national average. According to the production results, Giove stood out regarding PFT, PFC, NTT, NTC and a proper DC, where the 70% of spears measured L and XL. With regard to postharvest behavior, it was found that the lowest degree of dehydration was obtained by using bags and trays.