Scientific Journals of INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria)
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Diameter growth performance of tree functional groups in Puerto Rican secondary tropical forests
Get PDFAim of study: Understanding the factors that control tree growth in successional stands is particularly important for quantifying the carbon sequestration potential and timber yield of secondary tropical forests. Understanding the factors that control tree growth in successional stands is particularly important for quantifying the carbon sequestration potential and timber yield of secondary tropical forests. Yet, the high species diversity of mixed tropical forests, including many uncommon species, hinders the development of species-specific diameter growth models.Area of study: In these analyses, we grouped 82 species from secondary forests distributed across 93 permanent plots on the island of Puerto Rico.Material and Methods: Species were classified according to regeneration strategy and adult height into six functional groups. This classification allowed us to develop a robust diameter growth model using growth data collected from 1980-1990. We used mixed linear model regression to analyze tree diameter growth as a function of individual tree characteristics, stand structure, functional group and site factors.Main results: The proportion of variance in diameter growth explained by the model was 15.1%, ranging from 7.9 to 21.7%. Diameter at breast height, stem density and functional group were the most important predictors of tree growth in Puerto Rican secondary forest. Site factors such as soil and topography failed to predict diameter growth.Keywords: Caribbean forests; growth model; tropical forest succession; Puerto Rico
A mathematical model to estimate the volume of grey water of pesticide mixtures
Get PDFThe usual method to calculate grey water footprint does not take into account the volume of water required to dilute concentrations of pesticide mixtures in freshwater and it also depends on maximum concentration limit acceptable in water. We propose a model to estimate the grey water footprint of crops by calculating the volume of water necessary to dilute pesticide mixtures reaching freshwaters. The model requires short-term toxicity data from aquatic organisms based on EC50 values, soil pesticide half-life and soil sorption coefficient values, and does not require maximum concentration limit acceptable in water. The lixiviation rate and runoff rate of each pesticide was estimated by attenuation factor and by Soilfug model, respectively. The usefulness of the proposed model was illustrated by estimating the volume of grey water required to dilute the 17 most widely used herbicides in sugarcane crops of Brazil. The grey water footprint corresponding to the recommended agronomic dose for each herbicide varied between 4.20×106 m3 yr-1 and 1.20×1012 m3 yr-1 and the grey water footprint of the mixture of herbicides was 2.36×1012 m3 yr-1 in a cultivated area of 8.4×106 ha. These results establish the ranking position of each herbicide in the composition of the grey water footprint of mixture of herbicides. The rank of each herbicide could be used to create a label to be placed on the package of the pesticide, thus informing farmers about the volume of grey water per hectare due to the use of this herbicide
Leaf blade and petiole nutritional diagnosis for Vitis vinifera L. cv. Tempranillo by deviation from optimum percentage method
Get PDFDeviation from optimum percentage (DOP) is a diagnosis methodology for leaf analyses which expresses the deviation for each element with respect to its optimal concentration. This deviation is an individual index for each nutrient and allows the sorting of all the analyzed nutrients according to their limitations. A nutritional survey was undertaken over eleven years in La Rioja (Spain), to establish reference concentrations for the nutritional diagnosis of Vitis vinifera L., cv. ‘Tempranillo’ grafted on Richter-110. Reference concentrations for DOP methodology are proposed, and sensibility for the nutritional diagnosis was evaluated for blade and petiole analysis of N, P, K, Ca, Mg, Fe, Mn, Zn, Cu, and B at flowering and veraison phenological stages by comparison between DOP and sufficiency ranges (SR) methods. Results suggest that petiole has lower sensibility than blade to detect deficiencies or excesses of N, P, K, Ca, Mg, Zn, and Mn at veraison. In addition, petiole is a better tissue than blade to detect Fe and B deficiencies or excesses. Therefore, our results make possible the right choice between tissues, leaf blade or petiole, for a general nutritional diagnosis of ‘Tempranillo’ grapevines. On the other hand, it is possible to evaluate the status of each nutrient in each phonological stage analyzing both tissues and comparing the nutrient status to its references, DOP or SR, in the most adequate tissue
Development of virulence to Meloidogyne incognita on resistant pepper rootstocks
Get PDFThe root-knot nematode (RKN) Meloidogyne incognita is a major soil parasite of pepper crops in greenhouses in Southeast Spain. Due to the limitations of the use of soil fumigants, grafting plants on resistant rootstocks (R-rootstocks) has become an important alternative to chemical nematicides. The repeated use of R-rootstocks can bring about the selection of virulent populations capable of overcoming resistance. We carried out a six-year investigation on resistant rootstocks in a naturally M. incognita infested greenhouse, and found that two successive years of growing plants grafted on R-rootstocks Atlante (ATL) were sufficient to overcome resistance (galling index 1.5 and 5.6 in the first and second years respectively). A large variability was observed between several R-rootstocks. Two R-rootstocks (C19 and Snooker) behaved like ATL while two others (Terrano and DRO 8801) were not infected by RKN. Laboratory studies with the same R-rootstocks, inoculated with two nematode isolates (avirulent and virulent against ATL) confirmed the greenhouse results, indicating that some rootstocks may be infested by virulent populations and others may not. It suggests that different R-genes, which are differentially overcome by RKN, have been introgressed into the rootstocks. This may have consequences for the management of resistant rootstocks in the field
Genetic relationships between conformation characteristics and abilities for Menorca Dressage Movements in a Menorca horse population
No full textFunctional conformation and performance in Classic and Menorca Dressage are the main selection criteria in the Menorca Horse breeding program. Menorca Dressage is an alternative Classical Dressage discipline which is exclusive of the Menorca Island, but including a series of movements that the animals perform in the traditional festivities called “Jaleo Menorquín”. One of these movements involves the horse raising its forelimbs and standing or walking on its hindlimbs, which is called “el bot”. To make the Menorca horse breed more competitive in the equestrian market, it is necessary to understand the genetic background that characterizes the aptitude for Menorca Dressage and its relationship with conformation traits. The analysed data consisted of 15 conformation traits from 347 Menorca horses (200 males and 147 females), with 1,550 performance records in Menorca Dressage competitions. Genetic parameters were estimated using linear and threshold animal models. The heritabilities for heights and lengths were high (0.45-0.76), those for angulations and binary conformation traits were low to moderate (0.10-0.36) as were the scores for dressage performance (0.13-0.21). The results suggest that the analyzed traits could be used as an efficient tool for selecting breeding horses.Functional conformation and performance in Classic and Menorca Dressage are the main selection criteria in the Menorca Horse breeding program. Menorca Dressage is an alternative Classical Dressage discipline which is exclusive of the Menorca Island, but including a series of movements that the animals perform in the traditional festivities called “Jaleo Menorquín”. One of these movements involves the horse raising its forelimbs and standing or walking on its hindlimbs, which is called “el bot”. To make the Menorca horse breed more competitive in the equestrian market, it is necessary to understand the genetic background that characterizes the aptitude for Menorca Dressage and its relationship with conformation traits. The analysed data consisted of 15 conformation traits from 347 Menorca Horses (200 males and 147 females), with 1,550 performance records in Menorca Dressage competitions. Genetic parameters were estimated using linear and threshold animal models. The heritabilities for heights and lengths were high (0.45-0.76), those for angulations and binary conformation traits were low to moderate (0.10-0.36) as were the scores for dressage performance (0.13-0.21). The genetic correlations between the analyzed conformation and performance traits were null to high, ranging between -0.51 to 0.54, although they showed a high standard deviations of their marginal posterior distribution. The results suggested that shoulder angle and hindlimb traits may be the most important characteristics for horse ability in dressage, thus suitable for indirect selection especially for Menorca movement
Development of new gene-specific markers associated with salt tolerance for mungbean (Vigna radiata L. Wilczek)
Get PDFThirty eight novel microsatellite markers (SSRs) specific to candidate genes involved in salt tolerance were developed for detection of genetic variations in 12 mungbean genotypes variably adapted to salt stress. A 100 out of 124 putative alleles were found polymorphic between wild and cultivated genotypes (inter-specific, 80.65%), 65 were within cultivars of mungbean (intra-specific, 52.42%) and 52 were within wild genotypes (inter-specific, 41.94%). The polymorphism varied from 86.84% to 100%, while the number of polymorphic alleles ranged from 1 to 4 with an average value of 2.63 per locus. The polymorphism information content (PIC) values ranged from 0.326 to 0.875 with an average value of 0.671, which shows their effectiveness in genetic analysis. Cluster analysis resulted in the distribution of salt tolerant and susceptible genotypes in separate groups which revealed the presence of inherent variations among mungbean cultivars. These variations were explored effectively for SSR markers studies. The developed SSR markers may help along with already available markers to execute further research on mungbean. The markers may be coupled with specific loci linked with salt tolerance. The developed markers will help to identify the QTLs (quantitative trait loci) or other important genes. These markers can also be utilized for testing the purity of hybrids or diversity assessment of Vigna species for important agronomic traits
Feed prices and production costs on Spanish dairy farms
Get PDFThis paper analyses the impact of livestock feed prices and pasture quality on the long and short-term costs of milk production in a region of Spain (Navarre). The empirical results are obtained from the estimation of a flexible short-run cost function, followed by the approximation of long-run equilibrium based on the quasi-fixed factors adjusted to their optimal levels. The results reveal a high sensitivity of milk production costs to changes in livestock feed prices due to two reasons. One is that, as milk production expands, it tends to become technologically more intensive. The other is that, in the current structure of dairy farming, land input is suboptimal, particularly in the case of large farms and areas of poor pasture. The results reveal that short-run substitution between feed and livestock is a potential strategy for farms to respond to feed price increases. They also suggest that structural policies designed to strengthen the dairy sector’s competitiveness should vary according to agro-climatic conditions. In areas of poor pasture, herd growth might be used as a long-term measure to increase competitiveness through economies of scale; while the alternatives for farms in better-endowed regions also include extensification of dairy production.This paper analyses the impact of livestock feed prices and pasture quality on long and short-term milk production costs in a region in Spain (Navarre). The empirical results are obtained by estimating a flexible short-run cost function and then approximating long-run equilibrium by adjusting the quasi-fixed factors to their optimal levels. The results reveal a high sensitivity of milk production costs to changes in livestock feed prices due to two reasons. One is that milk production tends to become technologically more intensive as milk production expands. In optimum conditions, large dairy farms appear to become less land-dependent and to rely more heavily on purchased livestock feed. The other is that the current dairy farm structure shows suboptimal quantity of land, particularly by large farms and in areas with poor pasture quality. The results reveal that short-run substitution between feed and livestock is a potential strategy for farms to respond to feed price increases. The results also suggest that structural policies to strengthen the dairy sector’s competitiveness could be made to vary across agro-climatic areas. In poor pasture areas, herd growth might be used as a long-term measure to increase competitiveness through economies of scale; while the alternatives for farms in better-endowed regions also include extensification of dairy production
Impact of water temperature and structural parameters on the hydraulic labyrinth-channel emitter performance
Get PDFThe effects of water temperature and structural parameters of a labyrinth emitter on drip irrigation hydraulic performance were investigated. The inside structural parameters of the trapezoidal labyrinth emitter include path width (W) and length (L), trapezoidal unit numbers (N), height (H), and spacing (S). Laboratory experiments were conducted using five different types of labyrinth-channel emitters (three non-pressure compensating and two pressure-compensating emitters) commonly used for subsurface drip irrigation systems. The water temperature effect on the hydraulic characteristics at various operating pressures was recorded and a comparison was made to identify the most effective structural parameter on emitter performance. The pressure compensating emitter flow exponent (x) average was 0.014, while non-pressure compensating emitter’s values average was 0.456, indicating that the sensitivity of non-pressure compensating emitters to pressure variation is an obvious characteristic (p<0.001) of this type of emitters. The effects of water temperature on emitter flow rate were insignificant (p>0.05) at various operating pressures, where the flow rate index values for emitters were around one. The effects of water temperature on manufacturer’s coefficient of variation (CV) values for all emitters were insignificant (p>0.05). The CV values of the non-pressure compensating emitters were lower than those of pressure compensating emitters. This is typical for most compensating models because they are manufactured with more elements than non-compensating emitters are. The results of regression analysis indicate that N and H are the essential factors (p<0.001) to affect the hydraulic performance
Effects of Patagonian pine forestry on native breeding birds
Get PDFAim of the study: The objective is to assess the influences of the tree stand age and other forestry management practices on species richness, composition, and distribution of the Patagonian pine plantation bird assemblages. Area of Study: The work was carried out in forested plots of Ponderosa pine located at the Lanín National Park (Patagonia, Argentina).Material and Methods: Birds were sampled using 25 m fixed radius point counts, at four plots varying in age, management, and forest structure. Main Results: A total of 2090 individuals belonging to 34 bird species were observed, their numbers vary significantly depending on the different modes of plantation management. The population density of the 14 most abundant bird species was compared among the four plantation plots and ten species don’t show statistically significant differences in their population density among the different forest plots. The California Quail, the White-Crested Elaenia and the Southern House Wren showed higher densities in pine plantations with lower tree densities and fewer cutting treatments. The Diuca Finch had high densities in the younger plantations not subjected to any treatment. Research highlights: Most of these bird species are opportunistic and a few are found more regularly in these non-native woods than in other native forested or afforested areas. Our data suggest that a mixed scenario based on a mosaic of plantation with patches of native deciduous forest may help maximize the bird diversity in the management of northwestern Patagonian plantation landscapes.Keywords: Bird population; diversity; exotic plantations; Patagonia; tree-age
Natural production of Tuber aestivum in central Spain: Pinus spp. versus Quercus spp. brûlés
Get PDFAim of study: Tuber aestivum is the most widespread edible truffle, with increasing commercial interest. This species can produce carpophores with conifer hosts, in contrast with the inability of Pinus spp. to induce fruiting in other truffle species such as Tuber melanosporum. Therefore the objective is to compare the characteristics and carpophore production of T. aestivum brûlés associated with Pinus spp. versus Quercus spp.Area of study: We studied the natural habitats of T. aestivum in the Alto Tajo Nature Reserve in central Spain.Material and methods: During 5 years, we monitored the production of carpophores and brûlé size of 145 T. aestivum brûlés associated with Pinus nigra subsp. salzmanni and P. sylvestris and Quercus ilex subsp. ballota and Q. faginea hosts. Statistical treatment was performed using the Statistica Program v. 6.Main Results: The size of brûlés associated with Pinus was significantly smaller than that of brûlés associated with Quercus. However, carpophore production per brûlé, and especially for brûlés of similar size, was greater when the host plant was a pine. After accounting for brûlé size, the production of brûlés associated with Pinus spp. was 2.23 (95% CI, between 1.35 and 3.69) and 1.61 (95% CI, between 1.02 and 2.54) times greater than the production of brûlés associated with Quercus faginea and Q. ilex subsp. ballota, respectively.Research highlights: The considerable ability of Pinus nigra subsp. salzmanni and P. sylvestris to form effective brûlés and to produce carpophores of Tuber aestivum in natural conditions was clearly demonstrated, and suggest that those species can be of use in the culture of T. aestivum.Key words: Summer truffle; Tuber aestivum; truffle culture; truffle ecology; Pinus spp.; Quercus spp