ABSTRACT Irregular rainfall and the occurrence of droughts in tropical semi-arid regions have a negative impact on the quality and availability of water stored in reservoirs. The aim of this study was to evaluate the quality of water stored in an artificial reservoir in the tropical semi-arid region of Brazil during years of drought. The study area was the Pereira de Miranda reservoir, located in the district of Pentecoste, Ceará, Brazil. Seven water-sampling campaigns were carried out between April 2015 and September 2016. The variables to be analysed were chlorophyll-a (Cl-a), hydrogen potential (pH), electrical conductivity (EC), total nitrogen (Ntotal), total phosphorus (Ptotal), transparency (SD), fixed/volatile/total suspended solids (FSS/VSS/TSS), and temperature (T0); the trophic state index (TSI) was then calculated. The variables which better explained the variance in water quality were identified by principal component analysis (PCA). The waters of the Pereira de Miranda reservoir were classified as hyper-eutrophic throughout the study period and at each of the collection points. The PCA identified that the variability in water quality was determined by suspended sediment and nutrients, showing that the reduction in variables made it possible to obtain high explainability of the conditions of the reservoir during monitoring, saving time and resources on the analyses. In addition, the occurrence of severe drought resulted in low accumulated volumes, which intensified and made vulnerable the quality of the waters. As such, the Pereira de Miranda reservoir proved to be in a process of degradation, mainly due to anthropogenic action, intensified by climate factors.

RESUMO Objetivou-se com esse estudo caracterizar acessos de amendoim da coleção de germoplasma do CCA/UFC e verificar concordância entre os grupos botânicos preexistentes com as estimativas de diversidade genética. Para isso, foi conduzido um ensaio com 43 acessos de amendoim no delineamento em blocos casualizados com três repetições. Para caracterização dos acessos foram utilizados 21 descritores morfoagronômicos, os quais revelaram grande variação genética. O caráter massa de cem grãos se mostrou o principal fator discriminante, com porcentagem relativa de discriminação de 22,1%. Pelo agrupamento obtido com o método de ligação completa, foi possível visualizar no dendrograma a formação de sete grupos com base na distância generalizada de Mahalanobis. Pela análise dos componentes principais também foi constatada grande diversidade fenotípica entre os acessos da coleção. Os três primeiros componentes explicaram 81% da variação total. Posteriormente, foi construído um gráfico tridimensional para visualização da dispersão dos acessos, na qual se verificou a formação de oito grupos. Constatou-se concordância de média magnitude entre os grupos botânicos e diversidade genética, tanto pela classificação observada no dendrograma quanto pela dispersão gráfica, comprovando a dissimilaridade entre acessos de grupos botânicos distintos. Assim, cruzamentos entre acessos do grupo botânico Spanish ou Valência com aqueles pertencentes ao Virginia devem gerar populações-base com elevado potencial genético.

ABSTRACT The aims of this study were to characterize peanut accessions of germplasm collection of the CCA/UFC and check consistency between the pre-existing botanical groups to estimates of genetic diversity. For this were conducted a trial with 43 accessions of peanut in a randomized block design with three replications. To characterization were used 21 morphological descriptors, where revealed large genetic variation. The mass hundred grains trait showed the main discriminating factors, with relative percentage of 22.1%. The cluster obtained with the linkage complete method, it was possible to view the dendrogram the formation of seven groups based on the Mahalanobis distance. By principal components analysis was identified phenotypic diversity among genotypes. The first three components explained 81% of the total variation. Subsequently, built a three-dimensional scatter chart for access of visualization, eight groups being formed. There was medium magnitude of agreement between the botanical groups and genetic diversity, both by the dendrogram and graphic dispersion proving the dissimilarity between genotypes of different botanic groups. Therefore, crossings between group access botanical Spanish or Valencia with those belonging to the Virginia group should generate segregating populations with high genetic potential.