Scientific Journals of INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria)
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A new approach to assessing competition from trees on Nelder wheels
No full textAim of the study: To develop an index to describe the competition of trees of Eucalyptus spp. clones in different densities; also, to evaluate the productivity of the clones on Nelder wheels (NWs).
Area of study: Ten Eucalyptus spp. clones distributed in nine NWs, located in the northern state of Tocantins, Brazil.
Material and methods: A new competition index was formulated as the ratio of geometric areas and average cross-sectional areas of sampling units from different locations on the NW referenced to a unit taken in the center of it. Besides, two distance-dependent indices were tested to evaluate their performance in different spacings. The correlation between the competition indices and the variables height, diameter, volume and cross-sectional area, average distance and mortality percentage was evaluated. To check the difference in productivity between the clones we used MANOVA and discriminant analysis.
Main results: The Alba-Péllico index provides a better understanding of the competitive relationship between trees, as well as a better explanation of the competitive process in the NWs than the other indices evaluated. The variation in the basal area between the clones in the less dense locations, substantiates the characteristics of each clone or possible interferences of the location since in this condition they are free from the influence of spacing and competition. This shows that competition is more influential than other characteristics of sites and genotypes in the behavior in diameter, basal area and volume in the densest sites.
Research highlights: The characteristics of the Alba-Péllico index indicate good interpretation to understand the competitive relationship among trees since the results vary between 0 and 1, and the closer to zero the smaller or non-existence of competition
Effects of a megafire on the arbuscular mycorrhizal fungal community and parameters in the Brazilian Cerrado ecosystem
No full textAim of the study: To evaluate the effects of a mega-fire on the arbuscular mycorrhizal fungi (AMF) community and parameters in soils under Cerrado vegetation.
Study area: Chapada dos Veadeiros National Park, Goiás, Brazil. This site suffered the biggest fire in its history on October 10, 2017, with an affected area of 66,000 ha.
Material and methods: We analyzed AMF spore density, roots’ mycorrhizal colonization rate, easily extractable glomalin (EEG), as well as the AMF genera present. These parameters were evaluated in burned and unburned areas of five common phytophysiognomies of the region.
Main results: Fire presence immediately affected the mycorrhizal community parameters in Cerrado soils, which tended to increase afterwards. The presence of AMF genera did not differ between burned and unburned areas, with Acaulospora, Claroideglomus, Diversispora, Glomus, Funneliformis, Sclerocystis, and Gigaspora being present. The recovery of AMF community conditions in the Cerrado after fire events could also be observed in the mycorrhizal parameters evaluated, as the values of spore density, roots’ mycorrhizal colonization rate, and EEG were similar in the burned and unburned areas.
Research highlights: AMF diversity, and especially their community parameters, show great recovery after fire events, since they are crucial in processes like nutrient cycling and soil aggregation
Toxicological and ecotoxicological pressure due to pesticide use in Sancti Spíritus, Cuba
Full text linkAim of study: To quantify the toxicity and ecotoxicological pressure of pesticides in Sancti Spíritus province, Cuba, between 2011 and 2014.Material and methods: A longitudinal descriptive study was designed for the study period, to identify potential risks to the environment and human health associated with the use of pesticides. In order to determine the toxicity and ecotoxicity of pesticide use, ƩSeq (Spread equivalents), POCER (Pesticide Occupational and Environmental Risk) indicator, and the Toxic Load (TL) methodology of the Plant Health Cuban Institute were used.Main results: Corresponding to 62 chemical families, 124 active ingredients were applied in the province during the study period. Organophosphates, carbamates, pyrethroids, inorganic compounds (such as copper), dithiocarbamates, aryloxyphenoxypropionates, neonicotinoids, sulfonylurea, triazoles, and organochlorines predominated due to their frequency of use. Use of toxic-pesticides, lack of personal protection equipment amount others made workers, residents and applicators the toxicological modules with the highest risk of exposure. From the POCER results we found that aquatic organisms, persistence, and groundwater are the modules with the highest ecotoxicological pressure.Research highlights: With the use of the POCER indicator as well as ƩSeq, a more accurate assessment of toxicity and ecotoxicity from certain pesticide can be done instead of the TL equation currently used in Cuba. In addition substitution of the most toxic pesticides by less toxic ones could help to reduce synthetic pesticide pressure on humans and the environment. This study can help to develop policies and management practices to reduce the hazards of synthetic pesticide use in Cuba
Potential of VIS/NIR spectroscopy to detect and predict bitter pit in ‘Golden Smoothee’ apples
Full text linkAim of study: A portable VIS/NIR spectrometer and chemometric techniques were combined to identify bitter pit (BP) in Golden apples.Area of study: WorldwideMaterial and methods: Three different classification algorithms – linear discriminant analysis (LDA), quadratic discriminant analysis (QDA) and support-vector machine (SVM) –were used in two experiments. In experiment #1, VIS/NIR measurements were carried out at postharvest on apples previously classified according to 3 classes (class 1: non-BP; class 2: slight symptoms; class 3: severe symptoms). In experiment #2, VIS/NIR measurements were carried out on healthy apples collected before harvest to determinate the capacity of the classification algorithms for detecting BP prior to the appearance of symptoms.Main results: In the experiement #1, VIS/NIR spectroscopy showed great potential in pitted apples detection with visibly symptoms (accuracies of 75–81%). The linear classifier LDA performed better than the multivariate non-linear QDA and SVM classifiers in discriminating between healthy and bitter pitted apples. In the experiment #2, the accuracy to predict bitter pit prior to the appearance of visible symptoms decreased to 44–57%.Research highlights: The identification of apples with bitter pit through VIS/NIR spectroscopy may be due to chlorophyll degradation and/or changes in intercellular water in fruit tissue
The impact of tillage systems and crop residues on microbial mass and soil structure stability indices
Full text linkAim of study: This research investigated the effects of management practices, including plant residues and tillage practices, on soil stability indices, microbial biomass carbon, and the number of bacteria.Area of study: Northern Khorasan Province, Iran.Material and methods: This study explored the effects of the three year-old tillage systems of conventional tillage (CT), minimum tillage (MT), and no-tillage (NT) at three levels 0, 40, and 70% of plant residues on soil physical and microbiological properties for a rotation of three years (wheat, canola, and wheat). Variables measured in this study included the whole soil stability index, the normalized stability index, the percentage of aggregate destruction (PAD), the number of bacteria, and microbial biomass carbon.Main results: Management practices could affect variables, such as soil structure stability as well as the number of bacteria. The results also showed that soils of higher stability were more resistant to soil degradation. In addition, by reducing tillage and adding plant residues, the PAD index decreased significantly. NT and MT practices improved soil structure stability indices and significantly increased the number of bacteria as well as microbial biomass carbon in contrast to CT, what could be attributed to the increased soil organic matter.Research highlights: Reduced tillage practices showed the potential for enhancing soil physical quality only through improving aggregate stability. Therefore, NT with 70% residue retention was found to be suitable to improve soil sustainability indices and increased soil microbial population
Phenotypic diversity of horse breeds used in sports activities, employing multivariate analysis
Full text linkAim of study: Sports involving horses have notable financial importance. Breeds are evaluated to find the best-suited ones for a specific sport category. Phenotypic diversity using biometric markers was evaluated for Quarter Horse (QH), Arabic (AR), English Thoroughbred (ET), and Brazilian Equestrian (BE) horse breeds.Area of study: Mato Grosso do Sul-Brazil.Material and methods: Lengths, widths, and circumference measures of 268 horses were collected. These measures were used to estimate conformation indexes. The size-free canonical discriminant analysis was used to remove the size effect on the animal's shape. The similarity among breeds (by sex) was evaluated employing multivariate analysis (canonical analysis, MANOVA, principal components, Euclidean distances, and grouping through complete linkage), considering all linear measures and conformation indexes (included in the analysis of principal components).Main results: Four canonical variables (CANs), each one representing an equation to interpret the morpho-functionality of breeds “sustentation”, “structure”, “frame”, and “equilibrium”, were retained. The breeds presented differences when the CANs were simultaneously considered. Differences mainly were the size and the thickness of the body as well as the ability of the animal to move. ET, QH, and BE demonstrate a well-defined biometric profile. These three breeds clustered separately from AR breed.Research highlights: Canonical variables allow to verify the functional aptitudes since the responses were close to conformation indices commonly used as horse skill estimators. The implementation of these variables as selection criteria in horse breeding programs require further studies in larger populations of horses for a confirmation of the present results
Forage source (alfalfa hay vs wheat straw) and rumen undegradable to degradable protein ratio: Effects on growth performance, microbial protein yield, digestibility, blood metabolites, and behavior of Holstein dairy calves
Full text linkAim of the study: The effects of forage source (alfalfa hay; AH vs. wheat straw; WS) with rumen undegradable to degradable protein ratio [low ratio (LR) = 28:72; high ratio (HR) = 36:64] were evaluated in young dairy calves.Area of study: Arak, Iran.Material and methods: Forty-eight 3-d old female Holstein dairy calves (44.5 kg of BW) were allocated in four treatments: (1) AH with low dietary RUP:RDP ratio (AH-LR); (2) AH with high dietary RUP:RDP ratio (AH-HR); (3) WS with low dietary RUP:RDP ratio (WS-LR); and (4) WS with high dietary RUP:RDP ratio (WS-HR), being RDP and RUP rumen degradable and undegradable proteins, respectively. The calves weaned on d 53 of the experiment and remained in the study until d 73 of age.Main results: The average daily gain and feed efficiency were improved in dairy calves receiving HR diets compared to LR diets during the post-weaning period (p<0.05). The fecal score (p=0.03) and neutral detergent fiber digestibility (p=0.04) were improved when calves fed WS diets compared to AH diets. Feeding HR diets increased allantoin (p=0.04) and microbial protein yield, and reduced blood urea nitrogen concentration (p=0.03) compared to LR diets. Assessing the interaction effects of the experimental factors resulted that the greatest BW, wither height, and blood beta-hydroxybutyrate, and the lowest urinary N concentration were observed in the WS-HR treatment (p<0.05).Research highlights: Feeding WS with high RUP:RDP ratio is recommendable in dairy calves due to the improvement in gain and N efficiency
Development of a SNP parentage assignment panel in some North-Eastern Spanish meat sheep breeds
Full text linkAim of study: To validate two existing single nucleotide polymorphism (SNP) panels for parentage assignment in sheep, and develop a cost effective genotyping system to use in some North-Eastern Spanish meat sheep populations for accurate pedigree assignment.Area of study: SpainMaterial and methods: Nine sheep breeds were sampled: Rasa Aragonesa (n=38), Navarra (n=39), Ansotana (n=41), Xisqueta (n=41), Churra Tensina (n=38), Maellana (39), Roya Bilbilitana (n=24), Ojinegra (n=36) and Cartera (n=39), and these animals were genotyped with the Illumina OvineSNP50 BeadChip array. Genotypes were extracted from the sets of 249 SNPs and 163 SNPs for parentage assignment designed in France and North America, respectively. Validation of a selected cost-effective genotyping panel of 158 SNPs from the French panel were performed by Kompetitive allele specific PCR (KASP). Additionally, some functional SNPs (n=15) were also genotyped.Main results: The set of 249 SNPs for parentage assignment showed better diversity, probability of identity, and exclusion probabilities than the set of 163 SNPs. The average minor allele frequency for the set of 249, 163 and 158 SNPs were 0.41 + 0.01, 0.39 + 0.01 and 0.42 + 0.01, respectively. The parentage assignment rate was highly dependent to the percentage of putative sires genotyped.Research highlights: The described method is a cost-effective genotyping system combining the genotyping of SNPs for the parentage assignment with some functional SNPs, which was successfully used in some Spanish meat sheep breeds