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1.
Agricultural practice in the semi-arid region of Brazil is highly dependant on irrigation. As access to water is limited in
the region, there is a need to guarantee its efficient use, especially in small-scale farming schemes. Models adequately calibrated
for semi-arid conditions and for typical crops are useful tools for analysis of on-farm strategies to improve water use efficiency.
A physically based agrohydrological model, SALTMED, is calibrated and validated for carrots (Daucus carota L., Brasília variety) and cabbage (Brassica oleracea var. capitata), two of the main crops in small-scale irrigated agriculture in the northeast of Brazil. SALTMED is also calibrated for castor
beans (Ricinus communis L.) under rainfed conditions. The results demonstrated the suitability of the SALTMED model for simulating soil water dynamics
and crop yield in the area. Predicted time series of soil water content and matric potential of root zone showed good agreement
with observed values, as shown graphically and statistically. Using the calibrated and validated model, management scenarios
were analysed in terms of applied irrigation water, irrigation frequency, soil and crop types. Impact of climate change on
the irrigation water requirements was also briefly analysed for possible changes in annual temperature using two different
emission scenarios. Analysis of possible impact of climate change on temperature related to two emission scenarios on the
area showed an increase around 11% of the crop water requirement for carrots and cabbage, for the low emission scenario, and
around 17% for the high emission scenario. The analysis of management scenarios indicated possible over-irrigation in the
area. The simulation showed that the deficit irrigation was a useful water-saving strategy for the region. The simulations
also indicated that irrigation frequency affected crop water use and differed according to the soil type. 相似文献
2.
Genomic selection (GS) is a disruptive methodology that is revolutionizing animal and plant breeding. However, its practical implementation is challenging since many times there is a mismatch in the distribution of the training and testing sets. Adversarial validation is an approach popular in machine learning to detect and address the difference between the training and testing distributions. For this reason, the adversarial validation method in this research was implemented using probit regression to detect the mismatch in distributions and also to select an optimal training set. We evaluated the proposed method with 14 datasets, and the results were benchmarked regarding of using the whole reference population and simple random samples. We found that the proposed method is effective for detecting the mismatch in distributions and outperformed in prediction accuracy by 11.67% (in terms of mean square error) and by 5.35% (in terms of normalized mean square error) when the whole reference population was used as training sets. Also, in general, this outperformed some existing methods for optimal training designs in the context of GS. 相似文献
3.
Abelardo Gutiérrez Vicente Ruiz Enrique Moltó Gervasio Tapia Maria del Mar Téllez 《Crop Protection》2010
The Red Palm Weevil (Rhynchophorus ferrugineus Olivier) is one of the worst pests for palms, since it can completely destroy the plant. Its early detection is very difficult and when the action of the pest is discovered, normally it is too late for recovering the plant. Bioacoustic sensors provide a good alternative for early detection of this pest because larvae activity is audible while they excavate tunnels to feed. This work describes the different stages for the development of an original electronic device based on acoustic sensors for early detection of Red Palm Weevil larvae in the interior of palms. This device is based on characteristic frequencies possibly related to their feeding activity. The performed tests have demonstrated that is possible to detect two week old larvae activity studying the sound intensity around 2250 Hz in palms infested only with 5 individuals under controlled environmental conditions. The activity of other insects artificially situated in the interior of palms did not affect the response of the device, possibly because they produce different frequencies (in the range 5–7 kHz). Future work will be aimed at assessing the infestation levels. 相似文献
4.
Correa-Calderón Abelardo Angulo-Valenzuela Ismael Betancourth Fernando Oroz-Rojo Francisco Fierros-Castro Karina Macías-Cruz Ulises Díaz-Molina Raúl Avendaño-Reyes Leonel 《Tropical animal health and production》2020,52(1):203-209
Tropical Animal Health and Production - The objective of this study was to compare the fertility of Holstein heifers under cooling and inseminated with sexed semen during the summer versus winter... 相似文献
5.
Pedro Lopes Garcia Hugo Abelardo González-Villalba Renata Alcarde Sermarini Paulo Cesar Ocheuze Trivelin 《Archives of Agronomy and Soil Science》2013,59(14):1944-1962
ABSTRACTBlends of controlled-release urea (CRU) and conventional urea can be an alternative to conventional fertilization to improve nitrogen use efficiency (NUE) and reduce costs when applied as a single application to agricultural crops. Different indexes of NUE, grain yield, nutrient uptake and partitioning in maize (Zea mays L.) were investigated in field experiments. The treatments consisted of a single rate of 180 kg N ha?1 with different proportions of polymer-sulfur coated urea (PSCU) and conventional urea (U) applied incorporated at sowing (0.05 m below and 0.1 m to the side of the seed row) at two tropical sites (Site 1, Typic Haplustox; Site 2, Rhodic Haplustox) in Brazil. A control treatment (without urea-N) and a treatment with conventional urea management (UCM: 20% of urea-N applied as basal fertilizer and 80% of N applied as top dressing) were also included. This study demonstrates that blends of PSCU and U are efficient in supplying N throughout the maize cycle at a Typic Haplustox site when applied in a single application incorporated at sowing, resulting in high yields and adequate macronutrient uptake. PSCU improved NUE index compared to U and UCM. There was not response for N fertilization in the Rhodic Haplustox site. 相似文献
6.
In maize (Zea mays L.) breeding programs, selection among and within segregating progenies is based mainly on indirect selection criteria. A
better understanding of the environment influence on physiological attributes of maize inbred lines is important to the identification
and selection of superior inbred lines as well as to successful hybrid seed production. In this study, the size and form of
genotype (G) and genotype × environment (G × E) interaction effects for plant grain yield (PGY) and several physiological
attributes were examined for 12 maize inbred lines grown in four managed environments, represented by two seasons (Y) and
two nitrogen levels. Mixed model analysis revealed that the G effect was relatively high for attributes related to light capture,
phenology, early biomass production, and numerical components of PGY. The G × E interaction effect explained most of the variability
for PGY, harvest index (HI), and biomass production at maturity. Three-mode principal component analysis allowed us to: (1)
describe the associations among multiple attributes across environments, (2) reveal the form of the main patterns of G × E
interaction, (3) establish the importance of the genotype × year (G × Y) interaction for kernel number, HI, and biomass at
maturity in determining PGY, (4) identify promising genotypes of high-PGY across environments, and (5) detect genotypes of
similar response patterns for PGY but with a contrasting relative behavior for other attributes, which may permit the simultaneous
selection for grain yield and desired secondary traits. Such selection results would contribute greatly in the identification
of superior inbreds than selecting for grain yield alone.
相似文献
| Karina E. D’AndreaEmail: |
7.
Abelardo Aparicio Rafael G. Albaladejo Miguel Á. Olalla-Tárraga Laura F. Carrillo Miguel Á. Rodríguez 《Forest Ecology and Management》2008
While maximizing plant species richness continues to be central in the design, conservation and reforestation action plans, plant life histories are receiving increasing attention in assessments for the conservation of biodiversity in fragmented landscapes. We investigated the determinants of woody plant species (trees, shrubs and climbers) richness in the forest patches of the Guadalquivir river valley, a Mediterranean agricultural landscape with ∼1% forest cover. We analyzed three species richness variables, total, and those corresponding to species with short-distance (ballistic, barochorous, myrmecochorous and short-distance anemochorous) and long-distance (anemochorous, endozochorous, exozoochorous, hydrochorous and dyszoochorous) dispersal systems, which significantly characterize earlier and late successional stages, respectively. We selected eleven predictor variables related to habitat structure (patch area, shape, distances to the nearest patch and reserve, and general isolation), physical environment (temperature, precipitation, elevation, and lithological heterogeneity), and anthropogenic influences (disturbance and proportion of old-growth forest). We used ordinary-least-squares multiple regression (OLS) and the Akaike's information criterion (corrected for spatial autocorrelation) and derived indices to generate parsimonious models including multiple predictors. These analyses indicated that plant species richness increase primarily along with increasing patch area and decreasing disturbance, but also detected secondary effects of other factors when dispersal was considered. While the number of species with potential long-distance dispersal tended to increase in more isolated patches of areas with greater precipitation and lithological heterogeneity (e.g. highlands at the valley edges), the number of species with short-distance dispersal increased towards drier and less lithologically complex zones with shorter between-patch distances (e.g. central lowlands). Beyond emphasizing the need to consider dispersal in fragmentation studies, our results show that woody plant species richness would be favoured by actions that increase patch area and reduce anthropogenic disturbances particularly in lowland forests. 相似文献
8.
Luis Jimnez-Yan Abelardo Brito Gerard Cuzon Gabriela Gaxiola Toms García Gabriel Taboada Luis A. Soto Roberto Brito 《Aquaculture (Amsterdam, Netherlands)》2006,260(1-4):337-345
L. vannamei postlarvae are normally raised with a protein dense diet (50% protein) rich in fishmeal. Part of the protein is utilized for energy purpose instead of protein synthesis. Based on a previous energy partitioning study, the effects of two isoenergetic compounded feed treatments – animal protein (AP) and vegetable protein and carbohydrates (VPC) – upon growth efficiency and energy budget of shrimp postlarvae and early juveniles were determined. Recovered energy (RE) or production (P) after 50 days trial was similar (2 J day− 1) in both treatments, from PL14 to PL19. However, early juveniles discriminated between animal protein (116 J day− 1) and vegetable protein and carbohydrates (88 J day− 1). The difference in respiration indicated a higher heat increment with AP compared to VPC. At maintenance level, energy used was lower with AP than VPC treatment. Postlarvae and early juveniles employed protein as a main energy substrate (O:N < 20). Differences in the efficiencies observed in the calculated energy budget were attributed to the presence of carbohydrates in diet and not to the protein source. The advantage of incorporating vegetable protein source in the diet of harvesting shrimp may eventually contribute towards a reduction of fishmeal costs and waste products as well as to achieve sustainable shrimp farming. 相似文献
9.
Quintero-Elisea JA Macías-Cruz U Álvarez-Valenzuela FD Correa-Calderón A González-Reyna A Lucero-Magaña FA Soto-Navarro SA Avendaño-Reyes L 《Tropical animal health and production》2011,43(8):1567-1573
The aim of this study was to evaluate the effects of dose and application time of pregnant mare serum gonadotropin (PMSG)
on reproductive performance of hair sheep ewes synchronized with fluorogesterone acetate (FGA) under tropical conditions of
Northeastern Mexico. Ninety-nine hair ewes (63 Blackbelly and 36 Pelibuey) were treated with intravaginal sponges during 10 days.
After insertion of FGA sponges, ewes were divided into four groups, and PMSG was injected intramuscularly at doses of 100,
200, and 400 IU. Relative to FGA sponge removal, PMSG was administrated at −48 h, −24 h, and at sponge removal. PMSG was not
administered to the control group. Control ewes had similar (P > 0.05) lambing rate, fertility, and fecundity than those treated with 100 IU of PMSG, but lower (P < 0.05) percentages to these variables than those treated with 200 and 400 IU of PMSG. Time to estrus decreased linearly,
and ovulation rate increased quadratically as PMSG dose increased (0 to 400 IU). Administration of PMSG before sponge removal
increased (P < 0.01) response to estrus and decreased (P < 0.01) interval to estrus compared with control. Ovulation rate, lambing rate, fertility, and fecundity were not affected
(P > 0.05) by administration time of PMSG. Both dose and time of PMSG application did not affect (P > 0.05) pregnancy rate, percentage of single and multiple lambing, and prolificacy. In conclusion, results show that the
dose of 400 IU of PMSG administered before sponge withdrawal in an estrus synchronization protocol improved reproductive efficiency
of hair sheep ewes. 相似文献
10.
This paper applies linear mixed model analysis to 122 on-farm trials of commercial and near-commercial sunflower (Helianthus annuus L.) hybrids grown over 15 years in 32 locations of central Argentina to quantify increases in oil yield and to determine the contributions of change in both biotic stress resistance and yielding ability in favourable environments. The best linear unbiased predictors (BLUPs) from this analysis can be regarded as measures of ‘relative peak performance’ of hybrids in environments for which they were selected, and are a better measure of their adaptation compared to small trial sets of ‘historical’ hybrids. The BLUPs of 49 commercial hybrids released between 1983 and 2005 showed a genetic gain for oil yield of 11.9 kg ha−1 yr−1. Special purpose hybrids that were converted for single traits or that were developed for low-technology markets lagged by 5–15 years in terms of genetic gain. Genetic gains came about due to both an increase in the number of hybrids with resistance to the major biotic stress (Verticillium dahliae Klebahn) and a genetic gain in oil yield of 14.4 kg ha−1 yr−1 within these hybrids. Based on the data and the estimated time lag between commercial release and peak use, the improvement in oil and grain yield of conventional hybrids in central Argentina will be sustained until at least 2010, with evidence that the new germplasm pools still have substantial genetic variance to be exploited. 相似文献