Brazilian Semiarid Region Research Articles

Litter decomposition and nutrient release in different land use systems in the Brazilian semi-arid region

Climate and litter quality change the dynamics of soil organic matter (SOM) in agricultural systems, directly influencing the soil biological activity and, consequently, energy and nutrient cycling. This work evaluated the dynamics of organic carbon decomposition and nutrient release in litter in three land use management systems. The study was carried out under semi-arid conditions in Minas Gerais State, Brazil, using decomposition bags arranged in a randomized block design and four replications. The treatments consisted of three land use systems (native forest, corn, and cocoa) and seven evaluation times: 0, 30, 90, 150, 210, 270, and 330 days. Was evaluated dry matter production, litter decomposition in polyamide bags, and nutrient release (N, P, K, S, Ca, and Mg). Systems with native forest, cocoa and maize had similar average monthly litter production, a fact linked to the climate conditions. While in the semi-arid climate, the full-sun cocoa system showed a sudden oscillation in relation to the organic carbon content up to 330 days, the native forest and corn systems were more balanced, whitout significant changes. The higher litter C/N ratio in relation to the native and corn systems favors the maintenance of organic C levels in the soil. K release has a similar behavior in cultivated soils and occurs more quickly when compared to the native system. Regarding the other macronutrients, the soil in the cocoa production system showed the highest mineralization. Periods of accumulated precipitation accelerate litter decomposition and macronutrient release. The results of this study give more insight into the carbon dynamics and nutrient release from litter as a function of land use systems in a semi-arid region.

Coexistence and Spatial Distribution of Invasive and Sylvatic Container-Breeding Mosquitoes in City–Forest Ecotone within the Brazilian Semi-arid

Aedes species are vectors of the most significant arboviruses in Brazil with the greatest health and economic impact in the country. However, little is known about the factors that influence the distribution of Aedes, as well as other container-breeding mosquitoes, especially on the border between urban and forest environments. Here, we tested the effect of three phytophysiognomies within the city–forest ecotone in the Brazilian semi-arid region on the spatial distribution of vector mosquitoes. We also investigated the effect of rainfall on the spatial distribution and abundance of mosquitoes and described the interspecific interactions between invasive and native mosquito species. Immatures were sampled during the rainy seasons of 2019–2020 (October 2019 to February 2020) and 2020–2021 (November 2020 to February 2021). In each sampled location, 30 ovitraps were installed in shaded areas. There was a predominance of the Aedes mosquitoes, especially Ae. albopictus and Ae. aegypti, while three species of Haemagogus (Hg. spegazzinii, Hg. janthinomys and Hg. leucocelaenus) were rarely found. The sylvatic mosquito Ae. terrens was abundant in areas with lower anthropic influence and during higher rainfall regimes with minimal pluviometric variation. This rainfall was also favorable for the presence of the predatory mosquito larvae Toxorhynchites theobaldi. The abundance of invasive Aedes species showed positive correlations with each other and negative correlations with the sylvatic Ae. terrens. Our results demonstrate that human occupation and the rainfall regime affect the interactions between invasive and sylvatic species of container mosquitoes.

Cactus–sorghum intercropping combined with management interventions of planting density, row orientation and nitrogen fertilisation can optimise water use in dry regions

Some strategies can optimise the use of water in crops under deficit, either by increasing yield or by reducing actual crop evapotranspiration (ET), to promote the sustainable intensification of production systems. The objective was to evaluate how the spacing, planting orientation, nitrogen fertilisation and intercropping strategies impact the dynamics of water in the soil, ET partitioning, and water use indicators for forage cactus and cactus–sorghum intercropping. Four experiments were conducted between 2018 and 2020 in the Brazilian semi-arid region. In the first two sites (I and II), the cladodes of the intercropped forage cactus and sorghum were spaced at 0.10, 0.20, 0.30, 0.40 and 0.50 m with rows-oriented east–west and north–south. In site III, the intercropped rows were spaced at 1.00, 1.25, 1.50 and 1.75 m. Site IV, which contained the forage cactus crop exclusively, was treated with four nitrogen levels (50, 150, 300 and 450 kg N ha−1). The management interventions improved water use more by increasing dry matter than by reducing ET in the cropping system. Intercropping promoted the greatest increase in water productivity (130 %). Increasing N doses in the forage cactus-only crop reduced ET by up to 39 % but increased deep drainage losses by up to 365 %. The most promising management practices for optimising water resources were as follows: spacing of 0.10 m between cactus plants in the intercropping trial under east–west row orientation, as it promoted greater water use efficiency (76 %); spacing of 0.30 m in the north–south orientation; and row spacing of 1.50 m, as it improved water productivity (6.89 kg m−3). Thus, interventions in management should be adopted to optimise water use in intercropping systems with forage cactus, aiming at sustainable intensification in dry environments.

Mapping of aridity and its connections with climate classes and climate desertification in future scenarios – Brazilian semi-arid region

Brazil has the most populous and biodiverse semi-arid region in the world (Brazilian Semi-arid - SAB). However, in recent decades, clusters of desertification have emerged, a problem that could intensify from climate change. The objective of this study was to elaborate on the spatial distribution of areas susceptible to climatic desertification in the SAB, considering future climate change scenarios. Understanding this dynamic is essential for SAB's agri-environmental management. Aridity indices and proposition of climate classes for current condition (1970-2000) and future scenarios (2061-2080) of the Intergovernmental Panel on Climate Change (IPCC) were prepared, considering scenarios from Shared Socioeconomic Pathways: Optimistic (SSP 126) and pessimists (SSP 585). The results indicate that by the end of the century, the climate in the SAB should become significantly drier (Kruskal-Wallis = p-value < 0.05), with an intensification of the aridity index in SSP 585. In the scenarios, the expansion of more arid areas over humid climates could reach 56,500 km² (10%) in SSP 126 and 140,400 km² (24%) in SSP 585. Consequently, areas with high (622,400 km² to 706,300 km²) and very high (622,400 km² to 706,300 km²) are expected to expand. 4,400 to 21,700 km²) susceptibility to climate desertification in the SAB, respectively in scenarios SSPs 126 and 585. Confirming these projections would imply socioeconomic and ecological risks in the SAB.

Soil chemical attributes under west indian cherry fertigated with nitrogen and humic substances

The use of humic substances (HS) in the soil can increase the efficiency of nitrogen fertilizers and contribute to the increment in soil organic matter and plant nutrient availability. Hence, this study aimed to evaluate, in two production cycles, the effect of applying HS and different nitrogen (N) doses on the chemical attributes and organic matter fractions of a soil cultivated with West Indian cherry in the Brazilian semiarid region. The experiment was set up in split plots, arranged in strips with four replicates. The absence or presence of HS using KS100 as the source was tested in the plots, and N fertilization (50; 75; 100; 125 and 150% of the recommended dose), using urea, was tested in the subplots. Soil pH, H+Al, Al3+, and Na+, K+, P, Ca2+, Mg2+, Fe2+, Mn2+ and Zn2+ contents were determined, and cation exchange capacity and bases saturation (V %) in the 0-0.2 and 0.2-0.4 m layers were calculated. Analyses of stocks of total organic carbon and carbon (C) of the humic acid, fulvic acid and humin fractions, and humic substances were performed. It was possible to observe that, in the second production cycle of West Indian cherry, the soils showed higher contents of nutrients available to plants. Increase in N availability did not enable a clear trend in the behavior of chemical attributes and organic C stocks in the soil. Under the studied conditions, KS100 application allowed a reduction in the C stocks of the HS of the soil.

Antibacterial activity and anxiolytic-like effect of Ziziphus joazeiro Mart. leaves in adult zebrafish (Danio rerio)

Ziziphus joazeiro Mart. is an endemic plant of the Caatinga that presents a great socioeconomic importance for the Northeast and Semiarid Region of Brazil. In view of this, this study aimed to evaluate the antibacterial activity and anxiolytic-like effects of Ziziphus joazeiro Mart leaves in adult zebrafish (Danio rerio). The characterization of the main classes of metabolites was performed through chemical reactions. The antibacterial and antibiotic potentiating activity was evaluated by broth microdilution assays. The 96 h acute toxicity, open field test and anxiety models test was evaluated in vivo on adult zebrafish. The results obtained in the phytochemical prospection evidenced the presence of flobabenic tannins, leucoanthocyanidins, flavonois, flavonones, catechins, alkaloids, steroids, and triterpenoids. EEFZJ did not show antibacterial activity for all microorganism tested (MIC ≥ 1024 µg/mL), but reduced the concentration required for bacterial growth inhibition in combination with gentamicin and norfloxacin against multidrug-resistant strains of S. aureus (SA10) and E. coli (EC06), exhibiting synergistic effect with these antibiotics (p<0.0001). In the tests in vivo, EEFZJ was found to be nontoxic, performing reduced locomotor activity and demonstrated an anxiolytic-like effect in adult zebrafish via GABAergic and Serotoninergic systems (5-HT1, 5-HT2A/2C and 5-HT3A/3B).

Mammalian Roadkill in a Semi-Arid Region of Brazil: Species, Landscape Patterns, Seasonality, and Hotspots

Roadkill is one of the principal causes of the loss of biodiversity around the world. The effects of roads on mammals are still poorly understood in regions with a semi-arid climate, where many knowledge gaps persist. The present study provides an inventory of the mammalian species affected on highways in northeastern Brazil, as well as identifying roadkill hotspots and contributing to the understanding of how seasonality and the landscape may influence the roadkill patterns of wild mammals. A total of 6192.52 km of road were sampled in 53 field surveys conducted between 2013 and 2017. Landsat 8 satellite images and data from the MapBiomas platform were used to classify land use and cover for analysis. Buffers of 1 km, 5 km, and 10 km were created around the study roads to identify the landscape variables associated with roadkill events. Ripley’s 2D K-Statistics and the 2D HotSpot test were used to identify roadkill aggregations and hotspots; GLMMs were generated for the landscape variables and evaluated using the Akaike Information Criterion. The Kruskal–Wallis test was applied to investigate the potential effects of seasonality. A total of 527 wild animal carcasses were recorded as a result of vehicular collision. The species with the highest roadkill records were Cerdocyon thous, Euphractus sexcinctus, and Procyon cancrivorus, while two species—Leopardus emiliae and Herpailurus yagouaroundi—are considered to be under threat of extinction. For mammals in general, the best GLMM indicated an increase in roadkills with increasing density of local vegetation areas, and a decrease as urban areas increased. The model also found that the mammals were less impacted in the vicinity of a protected area. In the specific case of C. thous, the roadkill rate was lower when urban infrastructure was more common than dense vegetation; the rate increased as areas of dense vegetation increased. In the case of P. cancrivorus and E. sexcinctus, the best models of roadkill patterns included an area of exposed soil and sparse vegetation, respectively. Roadkill rates were higher in the rainy season for all the mammals, with the exception of C. thous. These results reflect the ecological characteristics of the species with the highest roadkill rates. The findings of the present study raise concerns with regard to the impact of highways on the populations of C. thous, as well as the region’s most threatened species. They also indicate the potential functionality of the local protected area, as well as identifying roadkill hotspots, which will support the development of effective mitigation measures.

Wild fauna as roadkill on a highway in the semiarid region of northeastern Brazil

The death of wild vertebrates run over by motor vehicles on highways is one of the main causes of the loss of wildlife diversity. The aim of the present study was to investigate the diversity of wild fauna in roadkill incidents on a stretch of highway in the semiarid region of Brazil. The survey was conducted between March 2020 and May 2021 through active searches using a motorcycle. Killed vertebrates were analyzed and photographed in situ. Wild fauna was studied based on ecological descriptors, speed of movement and average rate of roadkill incidents. We compared total observed richness to that expected using nonparametric estimators. A total of 464 road-killed vertebrates were represented by two species of amphibians, 17 reptiles, 17 birds and 10 mammals. Amphibians were the most affected, totaling 245 individuals. Colubridae was the family with the largest number of species affected. Boiruna sertaneja and Boa constrictor were the only medium-size to large snakes killed. Herpailurus yagouaroundi and Leopardus tigrinus are respectively categorized as “least concern” and “vulnerable” according to the IUCN. The species accumulation curves continued to rise, showing no sign of approaching to an asymptote. Chao 2 and Jack 2 were the main estimators for road-killed wild vertebrates considering total richness. The diversity reported here is considered to be underestimated and greater monthly sampling efforts are required. Conservation strategies are urgently needed for the protection of wild vertebrate fauna to mitigate the staggering loss of biodiversity caused by the construction and operation of roads and highways in Brazil.

Bioecological representations and social characteristics of students influence their attitudes toward wild vertebrates

BackgroundThe origin of different human emotions directed towards animals (whether in the utilitarian, affective, conflictual, or cosmological context) is strongly influenced by sociocultural factors, although our genetic predispositions also play an important role in the origin of these emotions. Such emotions guide people’s representations of different species, which in turn affect their attitudes toward them. For this reason, understanding the factors that guide such attitudes becomes a key element in making conservationist decisions. In this sense, the main objective of this study was to analyze how sociocultural characteristics and bioecological representations can influence students’ attitudes of empathy or antipathy towards vertebrate species; as well as which classes and species are related to greater and lesser support in people for their conservation.MethodsTo do so, 667 interviews were conducted with students from urban (n = 1) and rural (n = 2) schools in the Brazilian semi-arid region. We used mixed generalized linear models (GLMM) to examine the effect of social factors and bioecological representations on empathy and antipathy attitudes and multiple factor analysis (MFA) to examine the relationship between the biological characteristics of the animals (positive or negative) and the attitudes toward them (antipathetic or empathetic).ResultsThrough GLMM, we found that students from the urban area and from lower school levels are more extreme in their responses, more frequently expressing both empathy and antipathy towards wild animals. Regarding gender, women had a higher frequency of responses associated with aversion than men for species perceived as dangerous and poisonous (p < 0.001). Through the MFA, we found greater support (empathy) for the conservation of fish species (31.56%), birds (29.37%) and mammals (25.94%), with emphasis on the Red-cowled cardinal (Paroaria dominicana) and clownfish (Amphiprion ocellaris) species, and less support (antipathy) for reptile and amphibian species such as rattlesnakes (Crotalus durissus) and horned frogs (Ceratophrys joazeirensis).ConclusionsThe attitudinal ambivalence reflected by varying empathy for certain species and antipathy to others has important implications for wildlife conservation. Understanding the socioeconomic factors and emotions that influence attitudes towards animals can enable integrating educational strategies for the conservation of species, especially those which are culturally important.

Can the traditional use of native plant species in rural communities in the Brazilian semi-arid region be affected by global warming?

Extreme climate change events are capable of modifying the physiognomy of landscapes, impacting millions of people around the world. Consequently, the traditional knowledge of people residing in these regions about local natural resources may also be affected. To identify how the traditional use of native plant species can be influenced by a change in the availability of these species in a rural community in a semi-arid region, in a scenario of climatic extremes, we developed a Pressure Indicator for Use Preference (PIUP), seeking to identify the species under the greatest pressure of use. The study was carried out in the São Francisco Rural Community, in the Cabaceiras Municipality, in the semi-arid region of the Paraíba State, with 42 local informants. The species with the highest PIUP had their potential distribution for the year 2050 modeled using the HadGEM2-ES climate model under the RCP4.5 scenario, as an optimistic forecast, and the RCP8.5 scenario, as a pessimistic forecast. The construction of the models identified a potential increase in the coverage area of ​​all analyzed species, with a greater territorial extension for the RCP8.5 scenario. Myracrodoun urundeuva, Mimosa tenuiflora and Croton blanchetianus were the species with the lowest potential area growth for the year 2050. The high use of species, especially M. urundeuva, associated with reduced growth in a more arid environment is a worrying factor for the population structure of the species, as well as for rural communities that make representative use of the species.

Wind farm noise and anuran diversity patterns: a case study in Brazilian seasonal dry tropical forest

ABSTRACT Noise pollution contributes to the global biodiversity crisis, however the consequences of this pollution on anuran diversity patterns are poorly understood. This is especially true of less evident sources of noise like wind farms and highly exploited areas, as in the Brazilian semi-arid region. Here, we evaluated the influence of wind farm noise on anuran assemblages’ diversity at the Caatinga, a seasonal dry tropical forest in Brazil. We tested the hypothesis that wind farm noise negatively affects the diversity of anuran assemblages in terms of abundance, species richness and composition. Anurans were sampled in 19 temporary ponds along a noise gradient in two wind farms over a rainy season (March to August). A total of 2,047 individuals belonging to 20 species were recorded. Our results suggest that wind farm noise has a non-significant relationship with anuran diversity patterns (species richness, composition and abundance). To our knowledge, this is the first investigation into the effects of wind farm noise on anuran assemblages in the Caatinga dry forest. Despite our results suggesting that anuran diversity is insensitive to noise pollution caused by wind farms, identification of emerging threats is essential to mitigate impacts on anuran populations which are declining globally.

Method of 210Pb geochronological to estimate sedimentation rate in water reservoir in the Brazilian semiarid region

Dams are important reservoirs in semiarid regions providing the needs of the population and agricultural activities in an area in which intermittent rivers predominate. These reservoirs are subject to erosion processes that can cause sedimentation and affect the quality of the water in them. The method of dating sediments using 210Pb is well known and is used to establish a precise chronology of the sediments in places where abrupt changes in sedimentation conditions do not occur. The work aims to determine the sedimentation rate in five main tributary points of the dam located in the semiarid region of the state of Pernambuco, Brazil, using the geochronologic dating of the sediments by measuring 210Pb activity. The method used was the Constant Rate of Supply (CRS) model. Dating coincides with the date of the conclusion of the construction of the dam. The sedimentation rate grew with the increase in depth and presented a decline in both the rate and flow of the sediments over time. The most recent results presented a decrease in sedimentation rates. The greatest occurrence of the sedimentation rate was identified at points located at the entrance of the dam, which could be justified by the reduction in the average speed of final drainage due to the existence of the reservoir itself.

Diversidade morfoagronômica e identificação botânica de acessos de melão do nordeste brasileiro

ABSTRACT Melon (Cucumis melo L.) crops are grown in the Semiarid region of Brazil by small, medium, and large farmers, focused on domestic and international markets. However, melon is also grown by family farmers using their own seeds, which are important germplasm for melon breeding programs. Samples of these seeds were collected and stored in the Active Germplasm Bank of Cucurbitaceae from the Northeast Region at the Brazilian Agricultural Research Corporation (Embrapa Semiarid), and require more thorough studies for a better understanding of the existing variability. Thus, the objective of this work was to characterize sub-accessions and their respective endogamic progenies to assess the genetic variability between and among these accessions. Two experiments were conducted in a randomized complete block design, with three replications, using 11 quantitative and 8 qualitative descriptors: the first using seeds from 17 accessions from natural pollination, and the second using seeds from S1 progenies. Morphological data were used for comparisons between generations. The 17 accessions evaluated originated 24 sub-accessions, denoting variability between and among accessions and sub-accessions. A dendrogram developed based on the Unweighted Pair Group Method with Arithmetic Mean (UPGMA) showed the existing variability and, according to the newest melon classification, the groups identified were: makuwa, subgroup nashi-uri; and momordica and cantalupensis, subgroup prescott. The results showed a probable existence of introgression of alleles between different botanical groups, and some sub-accessions were not identified regarding their group by presenting variations in morphological characteristics, indicating the presence of new botanical groups.

Indicadores técnicos e econômicos do mamoeiro aos fatores de produção água e composto orgânico

ABSTRACT The objective of this study was to analyze technical and economic indicators of responses of papaya (Carica papaya L.) to the production factors water and organic compost, in a rural property with characteristic of family farming in the Semiarid region of Brazil. The study was conducted from August 2019 to July 2020, in the first crop cycle, in the municipality of Pentecoste, Ceara, Brazil. A Formosa papaya crop (cultivar Tainung 1) was established with spacing of 2.5 × 2.5 m, and irrigated by a micro-sprinkler localized system. A randomized block design was used, with a split-plot arrangement and four replications. The primary treatments consisted of four irrigation water depths (60%, 80%, 100%, and 120% of the crop evapotranspiration), and the secondary treatments consisted of four organic compost rates (0%, 50%, 100%, and 150% of the required rate for the crop). The irrigation water productivity of 5.38 R$ (BRL) m-3, related to the requirements of the production factors, on average, is five-fold the reference value for papaya crops under conventional production system. Rural credit allows the farmer to reach a social reproduction level with a papaya crop area that can be, on average, half of that needed under conditions without financing.

Implications of climate change on water availability in a seasonally dry tropical forest in the Northeast of Brazil

Climate change is already affecting life on Earth and mitigation measures must be taken, which require proper identification of the regions most vulnerable to these changes. This study assesses the impact of climate change on water availability (water surplus, water deficit and precipitation minus evapotranspiration) and climate classification across the Caatinga biome, located within the Brazilian semiarid region. To obtain the water surplus and water deficit, the water balance of Thornthwaite & Matther (1955) was applied considering the current scenario (historical series from 1961 to 2015); the optimistic scenario, considering the Representative Concentration Pathway (RCP) for a radiative forcing of 4.5 W.m-2 (RCP4.5), i.e., considering a temperature increase of 1.5 ºC and a reduction in rainfall from 15%; and pessimistic, considering a radiative forcing of 8.5 W.m-2 (RCP8.5), i.e. taking an increase in temperature of 4.0 ºC and a reduction in rainfall from 20%. The results showed that the Caatinga was strongly impacted, especially in the pessimistic scenario, with no water surplus and a negative water balance. For the optimistic scenario, only a small portion presented a water-surplus and a positive water balance. Projections also showed that a large part of the Caatinga changed from semiarid to arid climate.

Economic viability of irrigated cultivation of table cassava cultivars under phosphate fertilization

Phosphate fertilization of cassava cultivars leads to increased production costs that may be economically viable depending on the quantity used and the corresponding productivity. In this sense, the objective of the work was to analyse the economic viability of the irrigated cultivation of table cassava cultivars in response to the application of phosphorus doses in the Brazilian semiarid region. Two agricultural crops were conducted at the Experimental Farm Rafael Fernandes, Mossoró, RN, from June 2018 to April 2019 and from June 2019 to April 2020. The experimental design was in randomized blocks arranged in subdivided plots, with four replications. The doses of phosphorus (0, 60, 120, 180, and 240 kg ha-1 of P2O5) were applied to the plots and the table cassava cultivars (Água Morna, BRS Gema de Ovo, Recife and Venâncio) arranged in the subplots. The total costs for one hectare of cultivation were estimated and the gross income, net income, rate of return, and profitability index were calculated. The use of phosphate fertilizer was economically viable for the cassava cultivars studied in the two crops. The cultivars Água Morna, BRS Gema de Ovo, and Recife are the best cultivation options for the semiarid region of Rio Grande do Norteas they give high yields with the highest profitability. The Recife cultivar was the region's most profitable cultivation, with a profit ranging from R$ 40,331.07 ha-1 to R$ 57,603.46 ha-1 in both seasons, with an average recommendation of 120 kg ha-1 of P2O5.

Ecophysiology of Mentha piperita under saline stress and biostimulant in the Brazilian semiarid region

Brazilian semiarid region has water with high levels of salts that limit its use in agriculture, necessitating the adoption of strategies to reduce the impact of salinity. The objective of this study was to assess the effect of a biostimulant as a attenuating of mitigate saline stress on the growth, gas exchange, chlorophyll indices, and chlorophyll a fluorescence of Mentha piperita. The experiment was performed using a randomized block design, employing a 5 × 5 incomplete factorial schemes. This involved five different electrical conductivities of the irrigation water (ECw = 0.5, 1.01, 2.25, 3.49, and 4.00 dS m-1) and five doses of the biostimulant (Stimulate® = 0.0, 1.45, 5.00, 8.55, and 10.0 mL L-1). In total, nine combinations were generated using the Central Composite Design. Growth, gas exchange, chlorophyll indices, and chlorophyll a fluorescence were evaluated 45 days after irrigation with saline water. The results indicated that saline stress hindered the growth, gas exchange, chlorophyll indices, and photochemical efficiency of M. piperita. However, the biostimulant mitigated the adverse effects of salinity on the growth, gas exchange, and photochemical efficiency of M. piperita.

Socio-Environmental Vulnerability to Drought in the Seridó Potiguar, Brazil: Building Indicators

Imprecise in space-time and with damaging effects, drought as a historical-natural phenomenon of high complexity has been afflicting the population of the Seridó Potiguar Region, located in the state of Rio Grande do Norte, Northeast Brazil. For centuries, the region, of state relevance, is part of the Brazilian semiarid region. This reality produces socio-spatial, socio-economic, and political-institutional conflicts. Considering this, and the fact that drought in the 21st century continues to reach disastrous proportions and cause harm to human systems, this research aimed to offer a partial overview of the socio-environmental vulnerability of the Seridó region to drought, focusing on seven key municipalities: Bodó, Caicó, Currais Novos, Ipueira, Jardim de Piranhas, Jucurutu, and Parelhas. The Drought Vulnerability Index (DVI) was applied to these municipalities, composed of the sub-indices of Exposure, Susceptibility, and Adaptive Capacity, based on socio-economic and physical-environmental variables, which were calculated, classified, and cartographically represented using the RGB color composition. After analyzing the results, it was found that the municipalities ranged from low to moderate vulnerability, which can be justified by the compensation between the variables themselves and the good indicators regarding social assistance, mixed economy, hydraulic infrastructure, and means of coping with the semiarid region.

Yield and Quality of Naturally Colored Cotton Fiber Fertilized with Phosphorus Rates in the Brazilian Semiarid

ABSTRACT Cultivating naturally colored fiber cotton has excellent potential for the Northeast of Brazil. However, its cultivation in the semiarid occurs with low use of technology and inputs in soils with the low phosphorus content. This work evaluated the productivity and fiber quality of naturally colored cotton cultivars under phosphorus fertilization in the Brazilian semiarid region. The experimental design was randomized blocks, with treatments arranged in split plots and four replications. The five P doses were allocated in the main plot, and four cotton cultivars were in the subplots. Variance analyses were performed for the characteristics evaluated in each agricultural harvest. Tukey test was used to compare the averages for cultivars and agricultural harvests. Increased P availability increased productivity and fiber quality of naturally colored cotton cultivars. Maximum fiber yield was obtained at 240; 240; 199.11, and 60 kg ha−1 in the first crop, respectively. The maximum fiber length was reached at 80.86 kg ha−1 in the BRS Verde cultivar. The maximum uniformity was obtained with the 138.49 kg ha−1, and the cultivar BRS Topázio obtained greater uniformity. Fiber strength increased with the application of P2O5.

Multitrait selection in seedless grape hybrids in semiarid regions of Brazil

AbstractThe absence of seeds has been one of the most valued traits in grapes (Vitis spp.) for fresh consumption. However, the simultaneous selection of superior genotypes for multiple traits is complex. The objective of this study was to select genotypes of superior seedless table grapes in semiarid regions of Brazil. Multiple traits were considered by using the factor analysis and genotype–ideotype best linear unbiased prediction (FAI‐BLUP) selection index. A total of 110 grape progenies from 24 crosses were evaluated for traits of agronomic interest. Each hybrid was represented by a single vine plant, without experimental design or repetition. The mixed‐model methodology was used to predict the breeding values. The FAI‐BLUP index was used to select superior genotypes based on factor analysis and the genotype–ideotype distance. Four factors explained the 11 characteristics studied, with a variability of 81.84%. Desirable gains were observed for 10 of the 11 traits evaluated. The FAI‐BLUP index allowed the selection of superior seedless table grape hybrids, which can be used in the genetic improvement of grapevines. In conclusion, we report the selection of seedless table grape hybrids for our study to advance in the table grape breeding program in Brazilian semiarid regions.