Navegando por Autor "Oliveira, Claudio Marcelo Gonçalves"

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Clonal Arabica coffee resistant to Meloidogyne paranaensis and damage threshold on plants development
(Escola Superior de Agricultura "Luiz de Queiroz", 2019-05) Fatobene, Bárbhara Joana dos Reis; Gonçalves, Wallace; Oliveira, Claudio Marcelo Gonçalves; Guerreiro Filho, Oliveiro
Plants of Coffea arabica Icatu IAC 925 germplasm show resistance to Meloidogyne paranaensis under field conditions, but with variable rates of segregation. One mother plant, IAC 3, of Icatu IAC 925 was evaluated under controlled conditions through the reaction of its clones, obtained by somatic embryogenesis. Reproduction of nematodes in clones were compared with an open-pollinated progeny from the same mother plant, C. arabica cultivar Mundo Novo IAC 515-20, susceptible to nematodes, and Clone IAC 1, also susceptible and obtained by somatic embryogenesis. Open-pollinated progeny showed segregation to resistance and was classified as susceptible according to the reproduction factor. The average number of nematodes (eggs and J2) per gram of roots in clones was eight fold lower than that of open-pollinated progeny, and 51 fold lower than Mundo Novo IAC 515-20. Based on Seinhorst model, IAC 3 clone showed a tolerance limit of 7.7 nematodes per cm3 of soil, while in Mundo Novo the tolerance limit was 3.9 nematodes per cm3 of soil. These results revealed that clonal Arabica coffee nematode- resistant trees represent an alternative to the time consuming and expensive process inherent to conventional breeding strategies.
Parasitism of Meloidogyne exigua races 1 and 2 in coffee plants derived from Timor Hybrid
(Universidade Federal de Santa Maria, 2021) Pereira, Antonio Alves; Caixeta, Larissa de Brito; Fatobene, Bárbhara Joana dos Reis; Oliveira, Claudio Marcelo Gonçalves; Gonçalves, Wallace; Guerreiro Filho, Oliveiro
To investigate the degree of parasitism of two populations of Meloidogyne exigua, the gall index (GI) and the reproduction factor (RF) of M. exigua races 1 (Est E2) and 2 (Est E1) were analyzed in 47 progenies on F3:4 or F4:5 generation derived from the crossing between Coffea arabica cv. Catuaí Amarelo and Timor Hybrid. C. canephora cv. Apoatã IAC 2258 and C. arabica cv. Catuaí Vermelho IAC 144 were used as resistance and susceptibility checks, respectively. The genotypes that were classified as resistant or susceptible by RF were similarly classified by GI, showing a close relationship between both methodologies. The data also indicated no differences in virulence between the nematode populations, since the progenies showed similar resistance reactions to the M. exigua races 1 and 2. According to GI from the 47 mother plants evaluated, 27 progenies (57.4%) were classified as resistant to M. exigua races 1 and 2, with GI ranging from 0.0 to 1.4 and 20 progenies (42.6%) were susceptible with GI from 2.6 to 4.4. These results showed that most of the evaluated germplasm was very promising in relation to the development of new Arabica coffee cultivars with resistance to M. exigua.