Wallace Gonçalves

Fenóis, peroxidase e polifenoloxidase na resistência do cafeeiro a Meloidogyne incognita

Seedlings of two coffee cultivars were inoculated with the nematode Meloidogyne incognita: cv. Mundo Novo (susceptible) of Coffea arabica and cv. Apoata (resistant) of C. canephora. During the larval penetration and adult female phases of the parasite, evaluations were made on phenol content, peroxidase and polyphenoloxidase activities. In the two evaluations, no differences were observed in roots and shoots growth among inoculated and non inoculated seedling. For both cultivars, only in the first phase infected seedlings showed an increase in phenols as compared to their counterparts not inoculated. However, phenol values were higher in the second than in the first phase. The cv. Mundo Novo had always higher phenols content than Apoata. Only inoculated seedlings of the cv. Mundo Novo showed an increase of peroxidase activities in the first phase; but, both cultivars presented higher peroxidase activities in the second phase as compared to the first. Apoata seedlings had always higher peroxidase and polyphenoloxidase activities than Mundo Novo. Infected seedlings of the cv. Apoata showed in the first phase, only, an increase in polyphenoloxidase activity. Thin-layer chromatograms of phenolic extracts did not present any difference among inoculated and non-inoculated seedlings. Twenty three spots on the chromatograms were common to both cultivars, except that Apoata had a further nine spots not found in Mundo Novo and the later had a further eleven not found in the former.

Flutuação populacional do bicho-mineiro em cultivares de café arábica resistentes à ferrugem

The intensity of infestation of leaf-miner, Leucoptera coffeella (Guerin-Meneville) was investigated in coffee cultivars Obata IAC 1669-20 and Tupi IAC 1669-33, both resistant to the leaf rust agent, Hemileia vastatrix Berk. et Br., and Ouro Verde Amarelo IAC 4397, susceptible to this coffee disease, at field assays in Campinas, SP, Brazil. The incidence of coffee rust and presence of natural enemies, as well as the plant leafiness, were also observed. In Obata IAC 1669-20 and Tupi IAC 1669-33 cultivars the curves of population fluctuation revealed high occurrence of the coffee leaf miner between April and November. However analysis in the Ouro Verde Amarelo IAC 4397 cultivar demonstrated the occurrence of two peaks of infestation, the first in April-May and the second in August-September. Also, a higher index of damaged leaves was observed in Tupi IAC 1669-33 and Obata IAC 1669-20 cultivars in comparison to Ouro Verde Amarelo IAC 4397. This result may not indicate a higher susceptibility to L. coffeella of those cultivars, but otherwise could be the result of a better leaf retention, as a consequence of the leaf rust resistance exhibited by both cultivars. On the other hand, the damage observed in leaves from Ouro Verde Amarelo IAC 4397 cultivar is less frequent, probably in consequence of the high rate of leaf falling. Based on these observed differences, distinct strategies for this pest management are suggested.

Avaliação de progênies dos cafés Catuaí Amarelo e Catuaí Vermelho na região de Pindorama (SP)

Four progenies of the Catuai Amarelo and three of the Catuai Vermelho cultivars of Coffea arabica L. were evaluated for yield, as well as fruits and seed characteristics in a trial carried out at Pindorama Experimental Station. Caturra Amarelo and Mundo Novo cultivars of the same specie were used as control. Latin square 9 x 9 design was used. Each plot had six double plants (two plants per hole) planted 3 x 2 m in apart. Individual plant yield was recorded throughout eighteen years (1971-1988). It was analysed also the relation of ripe fruit weight to clean coffee weight; percentage of empty fruits; percentage of flat, peaberry and elephant beans; seed size and weight of 100 seeds for each individual plant. The Catuai Amarelo progeny CH 2077-2-5-62 gave the highest total yield and Caturra Amarelo LC 476 the lowest one. Yield oscillation was similar for the highest yielding Catuai progenies and the Mundo Novo and Caturra Amarelo standards. The results indicated that the Catuai Amarelo and Catuai Vermelho can be successfully grown at the Pindorama region.

Patogenicidade de Meloidogyne exigua e M. incognita raça 1 a mudas de cafeeiros

O presente trabalho teve por objetivo avaliar os danos causados por Meloidogyne exigua e M. incognita raca 1 a mudas de cafeeiros (Coffea spp.) Coffea arabica cv. Mundo Novo (LCP 515-20) e de C. canephora cv. Robusta (C 2258). O ensaio foi desenvolvido em casa de vegetacao, em vasos de um litro, contendo uma plântula cada um. Aos vinte dias apos o transplante, as plântulas foram inoculadas separadamente com 0, 2.000, 4.000 e 8.000 ovos de cada nematoide. As populacoes dos parasitos nas raizes e alguns parâmetros de crescimento das plantas foram avaliados aos 150 dias da inoculacao. Verificou-se que M. incognita raca 1 foi mais patogenica que M. exigua ao cultivar Mundo Novo. O cafeeiro C 2258 comportou-se como hospedeiro nao eficiente (FR < 1) de M. incognita raca 1, embora o crescimento das plantas tenha sido significativamente reduzido. M. exigua mostrou-se incapaz de parasitar o cafeeiro C 2258.

Melhoramento do cafeeiro: XLIII. seleção de cafeeiros resistentes ao bicho-mineiro

Several agronomic characteristics were studied in progenies from open pollinations and hybridizations of coffee trees C1195-5-6-1 and C1195-5-6-2. Both, resistant to the leaf miner (Perileucoptera coffeella), bloom profusely and are early ripening, characteristics of Coffea racemosa from which they originated via backcross to C. arabica. Hybrids of these two individuals with Icatu, Catimor, Hibrido de Timor and Catuai cultivars were evaluated. The first three cultvars, C. canephora x C. arabica backcross derivatives, are resistant to the leaf rust (Hemileia vastatrix) and the last a leading C. arabica cultivar has short stature and high yield capacity. The study of the progenies, undertaken in four experiments revealed that all these attributes, of such a diverse germoplasm, are genetically inheritable and are present in the progenies in different associations. The yield data and the fact that there are no antagonistic correlations among those attributes suggest that is possible to develop high yielding leaf miner resistant cultivars with other additional favorable traits, mainly resistance to leaf rust.

Inseticidas sistêmicos granulados no controle das ninfas móveis das cigarras e seus efeitos na produtividade de cafeeiros

The present research was conducted to evaluate the efficiency and yield increase by granular systemic insecticides to control cicades, mostly Quesada gigas, in two infested coffee plantations: one grown in sandy and the other in clay soils in the State of Sao Paulo, Brasil. The active ingredients tested were aldicarbe, at 10%, carbofura, at 5% and dissulfotom, at 2.5 and 10%, applied once in dosages normally used for coffee leaf miner control. An average reduction of 67.5% on mobile nymphs population was observed in the sandy soil and 54.1% in the clay soil plantations. The effect of the above treatments on productivity of coffee was tested over a four year period (1981-1985), and the percent yield increase was on the average: 175, 227 and 246% from aldicarbe, carbofura and dissulfotom, respectively.

Wild Coffea arabica resistant to Meloidogyne paranaensis and genetic parameters for resistance

Arabica coffee production is based on highly productive cultivars; however, these cultivars are susceptible to infestation by several biotic agents, including root-knot nematodes. Collections of wild Coffea arabica germplasm represent an important source of genetic variability for resistant cultivar development. In this study, 1046 plants derived from 71 wild coffee trees were evaluated with respect to Meloidogyne paranaensis resistance. In addition to information on plants reactions, we also evaluated the genetic parameters related to resistance. Progenies from the five most promising plants were also evaluated regarding resistance to M. incognita and M. exigua. The yield potential of selected plants was estimated through analysis of data for fruits harvested in 4 different years. Forty-seven plants were considered resistant based on reproduction factor values. The estimated heritability was high for all analyzed variables leading to substantial selection gain, mainly at the progeny mean level. On the basis of heritabilities and genetic correlations, we conclude that selection could be performed based on values of the gall and egg mass index. However, higher genetic gain could be obtained based on nematode count variables. A second experiment confirmed the reactions of the selected five plants to M. paranaensis, and multiple resistance was detected in three of them. The resistant accessions also have yield potential.

Antixenosis resistance to leaf miner Leucoptera coffeella in Coffea species

The coffee leaf miner, Leucoptera coffeella, is the most important pest of Coffea arabica plantations in Brazil, and all cultivars are susceptible to the insect. However, distinct reactions have been observed in other species, such as C. congensis and C. canephora. In this work, the occurrence of antixenotic response was surveyed in individuals of Coffea species, selected for resistance to the leaf miner at both field and laboratory conditions. Tests performed on young plants from C. arabica cultivars Icatu Precoce IAC 3282, Mundo Novo IAC 515-20, Tupi IAC 1669-33 and Catuaí Amarelo IAC 62 demonstrated that these were preferred for oviposition when pooled with seedlings from C. canephora cv. Apoatã IAC 2258. Apoatã was also preferred over C. racemosa for oviposition. Similar results were observed in tests using detached leaves, and higher amount of eggs was counted in the cv Obatã IAC 1669-20 and Catuaí Vermelho IAC 81, and lower oviposition frequency was observed in C. canephora cv. Guarini IAC 1598. C. congensis showed an oviposition frequency between C. arabica and C. canephora. Also, the results suggest that the frequency of oviposition is co-related with the plant resistance level, during larvae infection.

Coffee breeding: XLIII. selection of coffee trees resistant to the leaf miner (Perileucoptera coffeella)

Several agronomic characteristics were studied in progenies from open pollinations and hybridizations of coffee trees C1195-5-6-1 and C1195-5-6-2. Both, resistant to the leaf miner (Perileucoptera coffeella), bloom profusely and are early ripening, characteristics of Coffea racemosa from which they originated via backcross to C. arabica. Hybrids of these two individuals with Icatu, Catimor, Hibrido de Timor and Catuai cultivars were evaluated. The first three cultvars, C. canephora x C. arabica backcross derivatives, are resistant to the leaf rust (Hemileia vastatrix) and the last a leading C. arabica cultivar has short stature and high yield capacity. The study of the progenies, undertaken in four experiments revealed that all these attributes, of such a diverse germoplasm, are genetically inheritable and are present in the progenies in different associations. The yield data and the fact that there are no antagonistic correlations among those attributes suggest that is possible to develop high yielding leaf miner resistant cultivars with other additional favorable traits, mainly resistance to leaf rust.

Coffee breeding: XLIII. Selection of coffee trees resistant to the leaf miner.

Several agronomic characteristics were studied in progenies from open pollinations and hybridizations of coffee trees C1195-5-6-1 and C1195-5-6-2. Both, resistant to the leaf miner (Perileucoptera coffeella), bloom profusely and are early ripening, characteristics of Coffea racemosa from which they originated via backcross to C. arabica. Hybrids of these two individuals with Icatu, Catimor, Hibrido de Timor and Catuai cultivars were evaluated. The first three cultvars, C. canephora x C. arabica backcross derivatives, are resistant to the leaf rust (Hemileia vastatrix) and the last a leading C. arabica cultivar has short stature and high yield capacity. The study of the progenies, undertaken in four experiments revealed that all these attributes, of such a diverse germoplasm, are genetically inheritable and are present in the progenies in different associations. The yield data and the fact that there are no antagonistic correlations among those attributes suggest that is possible to develop high yielding leaf miner resistant cultivars with other additional favorable traits, mainly resistance to leaf rust.