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

The objective of the study was to determine the productivity of experimental hybrids of grain sorghum group in the Huastecas region, contrasting with commercial checks and parents. At Estación Cuauhtémoc, Tamaulipas, Mexico, three trials with 49 experimental and commercial hybrids were established during the spring-summer cycles 2005, 2006 y 2007 in dry land conditions. In 2008 in dry land, a trail was established with 28 hybrids and parents. In all cases we used a randomized block design with four replications. Experimental hybrids were identified as agronomically similar to commercials. One of the best hybrids was RB-104xRTx437, which produced 6403 kg/ha of grain. It was equal (p≤0.05) to: RB-Patron (6288 kg/ha), A. Amber (6028 kg/ha), DK-65 (5763 kg/ha) and RB-4000 (5700 kg/ha) was superior to Pioneer 82G63 (4796 kg/ha), Pioneer 84G62 (4256 kg/ha) and Z-400 (4218 kg/ha). The hybrid was also (p≤0.05) the earliest to flower (62 d) compared to to A. Ambar (65 d) and DK-65 (66 d). The experimental hybrids were higher yielding (2924 kg/ha), taller (17 cm), more precocious (-4.5 DF), had longer panicle length (0.9 cm) and exsercion (3,5 cm), and lower foliar diseases incidence (-0.24) than their parents. RTx437 was the best parent with grain yield (3598 kg/ha) equal (p≤0.05) to the hybrids.

The objective of this study was to select the most optimal statistic to estimate the experimental accuracy and to assess the Coefficient of Variation often used to estimate the validity of experiments. For the analysis, 406 trials were included; from research conducted at El Ejido Experimental Station and at cornfields of contributing producers of Azuero Region, Panama, during 2000-2013. To each trial it was calculated the various components of variance or Mean Square (MS), Coefficient of Variation (CV), Repeatability, Rank, Least Significant Differences (LSD), Standard Error (SE), Coefficient of determination (R2) of treatment and residual. We found that the CV is more related than repeatability with the overall mean of the experiment (correlation index of 0.57 vs. 0.24), thus being less robust to indicate experimental accuracy. Increasing the number of repetitions of experiments with the same MS Error reduced the SE and increased accuracy. The repeatability of the experiment was highly related to both treatments R2 (0.93) and the unexplained fraction model (0.87), in contrast with the CV (0.23 and 0.23, respectively). When repeatability and CV were linked to the DMS/Range ratio, it was found that repeatability is highly correlated (R2 = 0.76) with this ratio, while the CV provided an R2 of 0.18. This result suggests that the repeatability is a better indicator than the CV for good experimental accuracy.

The objective of this study was to determine the relationship between foliar emission and floral differentiation in False Horn plantains. Four studies were carried out on the Caribbean coast of Costa Rica between November 2000 and January 2014. Recoded variables were type and number of emitted leaves. In Study I (tall and dwarf cultivars, first ratoon) leaf emission was similar among tall (P=0.2417) and dwarf (P=0.5735) cultivars and between both of them (P=0.4170). In Study II (cv. Harton tall, plant crop) the vegetative phase of the meristem was observed in 100% of plants until the emission of leaf 21. The highest percentages of plants in which the meristem was in transition stages was 55%, 60%, 72% and 60%, and occurred in plants with 24, 25, 26 and 27 leaves, respectively. In Study III (cvs. Hartón tall and Hartón dwarf, second ratoom) differentiation was observed from leaf 20 in 10% and 60% of plants of tall and dwarf cultivars, respectively. A 100% of the dissected plants were in transition or at different stages of the reproductive phase by the time they reached leaf 24. In Study IV (Harton tall, second ratoon) it was not possible to find a relationship between the floral differentiation phase

The objective of this work was to describe the main histopathological results obtained from the different immune responses in L. vannamei after infection induced with V. parahaemolyticus. Inoculation bacterial was conducted in the Research Center for Ocean Sciences and Limnology at the University of Costa Rica betwen june to august 2011. The research used 40 shrimp of farms located in the Nicoyan Peninsula; each was injected an average of 2,0x106 CFU of V. parahaemolyticus. At the end of the period of infection, histopathological analysis were conducted on gills, subcuticular epithelium, hepatopancreas, intestine, gut lymphoid organ, hematopoietic tissue, striated muscle, nervous tissue, heart, among others. The main histological findings were melanized hemocytes, haemocyte infiltration, melanosis, spheroids type A, B and C, coagulative myonecrosis, pyknosis, among others, useful to determining in the health status of shrimp in particular, cytopathic effect of V. parahaemoltycus in systemic infections.

The aim of this study was to evaluate the effect of different soil humidity levels on the production of onion bulbs. Research was conducted at the Jorge Dimitrov Agricultural Research Institute, in the Bayamo municipality, Granma province, Cuba, during 2009-2010. Three soil moisture levels were evaluated: 100%, 75% and 50% of field capacity. Fifteen treatments and five varieties were used and were distributed in a complete randomized design. Twenty plants were selected at random from each treatment. The indicators that were evaluated in the bulbs were: mean weight (g), equatorial diameter (cm) and polar diameter (cm). Our results indicate that soil water deficit causes a significant reduction on bulbing size and bulbing mass, with the greater impact at 50% soil humidity.

The aim of this work was to characterize 111 native avocado (Persea americana Mill) cultivars with molecular and morphological markers. This study was carried out from 2009 to 2011 at Antioquia Department, Colombia, South America. The molecular analysis was performed with 38 AFLP (amplified fragment length polymorphism) and the primers E-ACT/M-CTC and E-AAC/M-CAA, that produced high levels of expected hetorozygocities for avocado from the municipalities of Valparaíso, Santa Bárbara and La Ceja. The native cultivars obtained from these places showed 100% genetic similarity with Hass. Twenty three shared AFLP loci where observed among all native genetic material and Hass, Fuerte and Reed from Antioquia. A UPGMA (Unweighted Pair Group Method with Arithmetic Mean) dendrogram constructed with the AFLPs and Nei genetic distance produced three clusters that grouped individuals that are geographically close and in places climatically similar. In addition, a principal components analysis (PCA) based on morphological traits produced three groups that are coincident with the dendrogram. The AMOVA (Analysis of Molecular Variance) estimated a significant but low Phipt (Fst analogous) value, indicating genetic differentiation among the Antioquia avocados. The results obtained in this work identified zones of Antioquia with native material that could potentially be used as injertation for the Hass variety, as a first step towards certification of avocado vegetative material in Colombia.

 The aim of this study was to determine the survival of pre-parasitic stages (eggs and larvae) of gastrointestinal nematodes (GN) in Bocashi made from cattle manure. The study was conducted at the facilities of the National University of Costa Rica (UNA) during 2010. Bocashi was made from cattle manure collected from a dairy farm located in Poasito de Alajuela, Costa Rica. Cattle manure contained 600 eggs from the Strongolyda suborder per gram (epg), specifically < 50 epg from Strongyloides papillosus, and < 50 epg from Trichuris spp. Approximately 20 random samples were taken from finished Bocashi and processed using the qualitative method of Sheater and the quantitative method of McMaster in order to identify and quantify eggs from GNs. Additionally, coprocultures were performed and total nematodes were extracted from Bocashi samples to determine the presence of GN larvae. Eggs from GNs were observed in Bocashi samples at very low concentrations, so quantification by the standard parasitological method was not possible. In all cases the eggs showed signs of degradation. No larvae from GNs were observed in coprocultures or in the total nematode extraction. In contrast, large numbers of bacterial-feeding nematodes were observed in Bocashi samples, whose presence is considered positive. We conclude that the conditions present during the preparation process of Bocashi substantially reduce the number of GNs at pre-parasitic stages and promote an increase in the number of beneficial organisms.

The objective of this study was to evaluate the effectiveness of two broadcast sowing of seeds equipments. The research was conducted on Ochomogo of Cartago in 2010. Seeds of canary (Phalaris canariensis) and linseed (Linum usitatissimum L) were used. The statistical model used was a model three-way classification. Measured variables were time spent to travel the stretch of work, quantity of seed sown broadcast per second, number of seeds dispersed and peso/m2. The seed distribution was 5.14 mg/sec in both species. Significant differences (p <0.05) between equipments and within them, show very difference download (p <0.01) between the different levels of acceleration and between the opening volley. Was significant (p<0.01) the effect of the addition of aggregates in the seed mix in the order of 21, 14 and 9 kg/ha of pure seed, mixed with 25% and 50% of aggregates, respectively. An analysis of response surface to determine the degree of acceleration required by the pump motor or the level of openness of the broadcast seed handy, along with the level of aggregates in the mix needed to achieve densities of 6, 8 and 10 kg/ha, in each broadcast equipments employee.

The aim of this study was to identify culinary practices associated with bean consumption in families from one rural population (Jesus of Atenas) and one urban (La Union of Tres Rios) of Costa Rica. The study was developed in 2005, in a sample of 475 families that usually prepare and eat beans (223 rural and 252 urban). In this families, the person responsible for the preparation of food was interviewed. The study showed a per capita beans consumption of 37.5 g/person/day (g/p/d) of raw weight. This consumption differs by geographic condition, being higher in rural area (46.8 + 25 g/p/d) than in urban areas (37.5 + 23 g/p/d) (F= 18.031, p= 0.000). The factors that were associated with consumption are different by area; in the rural area the factors were some characteristics of the person preparing bean, some preparation practices and the reasons manifested for consumption, whereas in urban areas the associated factors were only related to preparation practices.

The objective of this work was to identify the culinary and preservation practices for beans in a population rural (Jesus of Atenas) and an urban (La Union of Tres Rios) of Costa Rica. The study was developed in 2005, in a sample 475 families that prepare and consume beans (223 rural and 252 urban). In each of these homes, the person responsible for food preparation was interviewed and it is the key informant. The soaking beans before cooking was used mostly in the rural area (x2=14.435, p<0,001) and cooking methods employed in this area differ significantly from those used in the urban area (x2=28.535, p<0,001). In the rural area the most used cooking methods were conventional cooking and pressure cooking, but in the urban area the most common method was pressure cooking. The beans preservation methods applied to cooked beans do not different by area, the most common method found was refrigeration (x2=3.722, p=0.293).