Root-knot nematodes (RKN), Meloidogyne spp., have major economic impact on coffee production in Central and South America. Genetic control of RKN constitutes an essential part for integrated pest management strategy. The objective of this study was to evaluate the resistance of Coffea canephora genotypes (clones) to Meloidogyne spp. Sensitive and drought-tolerant coffee genotypes were used to infer their resistance using nematode reproduction factor and histopathology. Eight clonal genotypes were highly resistant to M. paranaensis. 'Clone 14' (drought-tolerant) and 'ESN2010-04' were the only genotypes highly resistant and moderately resistant, respectively, to both M. incognita races 3 and 1. Several clones were highly resistant to both avirulent and virulent M. exigua. Clone 14 and ESN2010-04 showed multiple resistance to major RKNs tested. Roots of 'clone 14' (resistant) and 'clone 22' (susceptible) were histologically studied against infection by M. incognita race 3 and M. paranaensis. Reduction of juvenile (J2) penetration in clone 14 was first seen at 2 to 6 days after inoculation (DAI). Apparent early hypersensitive reaction (HR) was seen in root cortex between 4 and 6 DAI, which led to cell death and prevention of some nematode development. At 12 to 20 DAI, giant cells formed in the vascular cylinder, besides normal development into J3/J4. From 32 to 45 DAI, giant cells were completely degenerated. Late, intense HR and cell death were frequently observed around young females and giant cells reported for the first time in coffee pathosystem. These results provide rational bases for future studies, including prospection, characterization, and expression profiling of genomic loci involved in both drought tolerance and resistance to multiple RKN species.

Mudanças climáticas e ilhas de calor urbanas | 7 ApresentaçãoO presente e-book busca contribuir para a discussão do fenômeno das Ilhas de Calor Urbanas (ICU's) no cenário nacional, utilizando, como pano de fundo, estudos desenvolvidos por pesquisadores da Universidade de Brasília com apoio da Fundação de Apoio à Pesquisa do Distrito Federal -FAP-DF pelo edital 06/2017. Dado o processo de urbanização acelerado e concentrado, é de fundamental importância colocar em pauta os impactos advindos das ICU's, tanto no meio acadêmico quanto no universo dos tomadores de decisão que modificam a paisagem urbana constantementepolíticos, empresários e a sociedade organizada.