Cultivars Of Coffea Arabica Research Articles

Biochemical responses of coffee resistance against Meloidogyne exigua mediated by silicon

Coffea arabica cultivars Catuaí 44 and IAPAR 59, susceptible and resistant, respectively, to the root knot nematode Meloidogyne exigua, were grown in pots containing Si‐deficient soil amended with either calcium silicate (+Si) or calcium carbonate (−Si). There was an increase of 152 and 100%, respectively, in Si content of root tissue of cvs Catuaí 44 and IAPAR 59 in the +Si compared to the −Si treatment, but no significant difference between Si treatments for calcium content. Plants, assessed 150 days after inoculation (d.a.i.) showed that the number of galls (NG) and number of eggs (NE) significantly decreased by 16·8 and 28·1% respectively, for susceptible cv. Catuaí 44 in the presence of Si, whilst both NG and NE were significantly lower for cv. IAPAR 59 compared to the susceptible cultivar regardless of Si treatments. In a separate experiment, biochemical assays were carried out 5 and 10 d.a.i. There was no significant difference between Si treatments and cultivars for concentration of total soluble phenolics. The concentration of lignin‐thioglycolic acid (LTGA) derivatives significantly increased by 11·5% in roots of nematode‐inoculated plants of susceptible cv. Catuaí supplied with Si. In roots of inoculated plants of resistant cv. IAPAR 59, the increase was 23 and 10%, respectively, for treatments with and without silicon. Peroxidase (POX), polyphenoloxidase (PPO) and phenylalanine ammonia lyase (PAL) activities significantly increased in roots of inoculated plants compared with roots of non‐inoculated plants, regardless of cultivar or Si treatment. In +Si treatments at 10 d.a.i., POX activity in roots of nematode‐inoculated plants of cvs Catuaí 44 and IAPAR 59 increased by 39·9 and 31·3%, respectively; PPO increased by 54·9 and 56·1%; and PAL activity was also higher at 26·6 and 62·9%. It was concluded that supplying Si to coffee plants increases root resistance against M. exigua by decreasing its reproductive capacity.

Atributos fenológicos e agronômicos em cultivares de cafeeiro arábica

O objetivo deste trabalho foi avaliar o efeito do ano agrícola sobre os atributos fenológicos e agronômicos em diferentes cultivares de cafeeiro arábica. Os atributos fenológicos determinados foram estádios de frutificação, de gema dormente até fruto seco e duração do ciclo. Como atributos agronômicos, foram avaliados o rendimento, a produtividade, os tipos e o tamanho de grãos. O período entre antese até fase chumbinho não variou entre as cultivares para o ano agrícola 2004/2005, já para o ano agrícola seguinte a cultivar 'Icatu Precoce' apresentou antecipação da fase chumbinho, e a cultivar 'Obatã' atrasou o início do ciclo fenológico em relação às demais cultivares estudadas. A duração do ciclo variou com o ano agrícola, o que possibilitou a confirmação da influência dos efeitos ambientais nessa característica. Os atributos agronômicos (produtividade, rendimento, tipo e tamanho de grãos), independentemente das cultivares, também variaram com o ano agrícola.

Autonomy and network modulation of photosynthesis and water relations of Coffea arabica in the field

The degree of connection between leaf gas exchange and leaf water potential, and the autonomy of these variables in relation to meteorological conditions were determined in three cultivars of Coffea arabica during clear and cloudy days. High values of vapor pressure deficit, air temperature and photosynthetic photon flux density resulted in low leaf autonomy during a clear day, irrespective the degree of connection among leaf physiological variables. Tight synchronization between physiological and meteorological variables was considered one important cause of net photosynthesis (P N) decreasing during a clear day. In contrast, diurnal P N was around three times higher on a cloudy day, when all cultivars presented high autonomy. Principal component analyses corroborated autonomy results revealing unambiguous opposition between leaf physiological and meteorological vectors, besides less leaf physiological variability throughout the clear day. Despite these general responses during clear and cloudy days, there were significant differences among studied cultivars. Leaf autonomy was an important reference to evaluate C. arabica under environmental stress and should be taken into account when selecting cultivars under field conditions.

Selection for durable resistance to leaf rust using test-crosses on IAPAR-59 and Tupi IAC 1669-33 cultivars of Coffea arabica

The aim of this study was to identify plants of the IAPAR-59 and Tupi IAC 1669-33 coffee cultivars with less defeated resistance genes by the rust races present at IAPAR (Londrina, Paraná State, Brazil) using test-crosses. Eighteen test-crosses derived from hybridizations between 'IAPAR-59' or 'Tupi IAC 1669-33' with susceptible coffee to the rust disease were evaluated. Six hybrids were used as susceptible standards originated from hybridizations between two susceptible coffee plants. Many parental plants of the 'IAPAR-59' and 'Tupi IAC 1669-33' presented more defeated resistance genes against rust races present at IAPAR than others of these cultivars or the genes were in heterozygous, because of segregant susceptible plants observed in some test-crosses. The test-crosses were very efficient to identify plants with less defeated resistance genes to the H. vastatrix. Coffee plants considered resistants would must be made test-crosses to verify which plants presented less and/or more defeated genes in homozygous.

Susceptibilidade de seis cultivares de café arábica às moscas-das-frutas (Diptera: Tephritoidea) em sistema orgânico com e sem arborização em Valença, RJ

The infestation indices by fruit flies were determined for six cultivars of Coffea arabica L. in shaded and unshaded systems under organic management. The experiment was set in a completely randomized design with a split-split-plot arrangement and four replicates. A 250g-sample of maturing fruits per plot was harvested in May 2005. The cultivars Icatu Amarelo and Catucaí Amarelo were the least susceptible to attack by tephritids in both systems. As for lonchaeids, Oeiras, Catucaí Amarelo and Catuaí Vermelho were the least susceptible cultivars in the shaded system, and there was no difference among the cultivars in the unshaded system. The following tephritid species were obtained: Ceratitis capitata (Wiedemann), Anastrepha fraterculus (Wiedemann) and A. sororcula Zucchi (Tephritidae). Lonchaeids were represented by Neosilba bifida Strikis & Prado, N. certa (Walker), N. glaberrima (Wiedemann), N. pendula (Bezzi), N. pseudopendula (Korytkowski and Ojeda), Dasiops rugifrons Hennig, Neosilba n.sp.10 and Neosilba n.sp.14.

Changes in content and biosynthetic activity of caffeine and trigonelline during growth and ripening of Coffea arabica and Coffea canephora fruits

Caffeine and trigonelline are major nitrogenous alkaloids found in coffee seeds. Accumulation of these alkaloids in two cultivars of Coffea arabica and in a cultivar of Coffea canephora seeds was monitored. Growth stages are specified by letters, A to G. They correspond to the pinhead and small (A), rapid expansion and pericarp growth (B), endosperm formation (C), early dry matter accumulation (D), mature (green) (E), ripening (pink) (F) and fully ripened (red) (G) stages. Caffeine and trigonelline content increased at stages D and E. The concentrations of caffeine in ripe seeds (stage G) of the two cultivars of C. arabica and C. canephora seeds were respectively 1.0% and 1.9% dry weight. A high biosynthetic activity of caffeine, which was estimated via the incorporation of [8- 14C]adenine into purine alkaloids, was found in whole fruits (perisperm and pericarp) in stages B and C, and in developing seeds (endosperm) in stages D and E. The biosynthetic activities of caffeine were reduced in both pericarp and seeds in stages F and G. In C. arabica cv. Mokka and in C. canephora, the transcripts of CmXRS1, CTS2 and CCS1, three N-methyltransferase genes for caffeine biosynthesis, and of methionine synthase gene ( MS) were detected in every stage of growth, although the amounts of these transcripts were significantly less in stage G. The pattern of expression of genes for caffeine synthesis during growth is roughly related to the in situ synthesis of caffeine from adenine nucleotides, although exceptions were found in the very early and later stages of fruit growth. The amounts of the transcripts of CmXRS1, CTS2 and CCS1 were higher in seeds than in pericarp, but reverse was true for MS transcripts in developing coffee fruits. Similarly, caffeine synthase ( N3-methyltransferase) activity was also higher in seeds than in pericarp. Concentrations of trigonelline in ripe seeds (stage G) of C. arabica cv. Mokka, C. arabica cv. Catimor and C. canephora were ca. 1.3%, 1.0% and 1.4% of dry weight, respectively. High biosynthetic activity of trigonelline was found in young fruits (stages A–C) and in the pericarp of developing fruits (stage E). The biosynthetic activity was reduced markedly in seeds at stages F and G. These results suggest that active trigonelline biosynthesis occurs in the pericarp of coffee fruits. Although the final concentration of caffeine and trigonelline varies in the three Coffea plants, the patterns of fluctuations of the caffeine and trigonelline biosynthetic activity in all Coffea plants are all similar.

CARBON GAIN IN COFFEA ARABICA DURING CLEAR AND CLOUDY DAYS IN THE WET SEASON

Three cultivars of Coffea arabica, Catuaí Vermelho IAC 81, Icatu Amarelo IAC 2944 and Obatã IAC 1669–20, were evaluated in relation to leaf gas exchange and potential photochemical efficiency of photosystem II under field conditions on clear and cloudy days in the wet season in southeast Brazil. Independent of levels of irradiance, leaf water potential (υleaf) values were always higher than the minimum required to affect daily net photosynthesis (PN). PN, stomatal conductance (gs), leaf transpiration (E) and the index of photochemical efficiency (Fv/Fm) declined on a clear day in all cultivars. The depression of leaf gas exchange and Fv/Fm (specially around midday) caused a strong decrease (about 70 %) in daily carbon gain on a clear day. Under cloudless conditions, gs and PN were correlated with the air vapour pressure deficit (VPDair), but not with photosynthetic photon flux density (PPFD) values. On a cloudy day, the daily carbon gain was barely limited by PPFD below 800 μmol m−2 s−1, the Fv/Fm values showed a slight decrease around midday, and gs and PN were positively correlated with PPFD but not with VPDair. By contrast, irrespective of the contrasting irradiance conditions during the day, PN and E were correlated with gs.

Estimativa do teor de cafeína nas sementes de café baseada na sua concentração nas folhas de mudas e de plantas adultas

This work was conducted in the Iapar Experimental Station at Londrina, state of Paraná, Brazil. Leaf, fruit peel and seed samples were collected in an experimental site of Coffea Arabica cultivars Mundo Novo, Catuaí, Icatu, Sarchimor and Laurina and of Coffea canephora, cultivar robusta. The objective was to save time in the plant selection with different caffeine content with previous determination of the alkaloid in the leaf. Samples composed by the first, third, and sixth pair of leaves counted from the lateral branch in the following coffee fruit stages: initial growth, fruit filling, green formed gram and full maturation. Fruit samples were collected in the bearing stage. Part of the fruits were sown to obtain seedlings from which were colleted the first and third pair of leaves. Plant materials were dried, ground and then used for the caffeine termination. Caffeine was extracted by the hot water method and determined by spectrophotometry at 273nm. The results showed that for the both coffee species the caffeine content in the first and third pair of leaves of the seedlings increased linearly with increasing caffeine content in the seeds of the plants from the same variety in the field. Therefore, the first and the third pair of leaves of the seedlings were considered to be efficient to estimate of the caffeine content in the seeds of the mature plants. Under field conditions the first pair of leaves showed caffeine content higher than older leaves, mainly for the Coffea canephora. Coffee fruit in the maturation stage presented the lowest caffeine content in the leaves. The first pair of leaves sampled in the beginning of fruit growth was the most efficient plant material to estimate the caffeine content in the seeds as compared with the older leaves and with the more advanced time of the fruit development. The alkaloid contents were slightly lower in the fruit peel (shell + parchment) as compared with seeds. The caffeine content in the seeds increased linearly with increasing N content

Genetic polymorphism among 14 elite Coffea arabica L. cultivars using RAPD markers associated with restriction digestion

Knowledge of the genetic variability among genotypes is important for the transfer of useful genes and to maximize the use of available germplasm resources. This study was carried out to assess the genetic variability of 14 elite Coffea arabica cultivars using random amplified polymorphic DNA (RAPD) associated with a prior digestion of genomic DNA with restriction endonucleases. The accessions were obtained from the Coffea collection maintained at the Instituto Agronômico do Paraná (IAPAR), located in Londrina, Paraná, Brazil. Twenty-four informative RAPD primers, used in association with restriction enzymes, yielded 330 reproducible and scorable DNA bands, of which 224 (68%) were polymorphic. The amplified products were used to estimate the genetic variability using Dice's similarity coefficient. The data matrix was converted to a dendrogram and a three-dimensional plot using principal coordinate analysis. The accessions studied were separated into clusters in a manner that was consistent with the known pedigree. The associations obtained in the dendrogram and in the principal coordinate analysis plot suggest the probable origin of the Kattimor cultivar. The RAPD technique associated with restriction digestion was proved to be a useful tool for genetic characterization of C. arabica genotypes making an important contribution to the application of molecular markers to coffee breeding.

Detection by simple sequence repeat markers of introgression from Coffea canephora in Coffea arabica cultivars

AbstractMicrosatellites or simple sequence repeats (SSR) were used to assess polymorphism among 16 Coffea arabica and four Coffea canephora accessions, and to identify DNA introgression fragments from C. canephora in four C. arabica lines. Thirty‐one primer pairs allowed for the identification of 92 polymorphic alleles distributed over 37 loci. The C. arabica accessions derived from the genetic bases ‘Typica’ and ‘Bourbon’ were grouped separately according to their genetic origin. Two genotypes derived from a spontaneous hybrid (C arabica×C. canephora) were classified with the C. canephora accessions from Central Africa. Coffea canephora from West Africa were separated from the other accessions studied. Four alleles related to introgression (i.e. present in C. canephora and introgressed lines, and absent in C. arabica) were identified. The SSR markers were used successfully for characterization of a particular cultivar (‘Veranero’) from Costa Rica, which is known for its late maturity.

AFLP analysis of genetic diversity within and among Coffea arabica cultivars.

Genetic diversity of Coffea arabica cultivars was estimated using amplified fragment length polymorphism (AFLP) markers. Sixty one Coffea accessions composed of six arabica cultivars, including Typica, Bourbon, Catimor, Catuai, Caturra and Mokka Hybrid, plus two diploid Coffea species, were analyzed with six EcoRI- MseI primer combinations. A total of 274 informative AFLP markers were generated and scored as binary data. These data were analyzed using cluster methods in the software package NTSYSpc. The differences among cultivars at the DNA level were small, with an average genetic similarity of 0.933. Most accessions within a cultivar formed a cluster, although deviant samples occurred in five of the six cultivars examined due to residual heterozygosity from ancestral materials. Among the six cultivars fingerprinted, the highest level of genetic diversity was found within the cultivar Catimor, with an average genetic similarity of 0.880. The lowest level was found within Caturra accessions, with an average genetic similarity of 0.993. Diversity between C. arabica and two other Coffea species, Coffea canephora and Coffea liberica, was also estimated with average genetic similarities of 0.540 and 0.413, respectively, suggesting that C. canephora is more closely related to C. arabica than is C. liberica. The genetic variation among arabica cultivars was similar to the variation within cultivars, and no cultivar-specific DNA marker was detected. Although arabica cultivars appear to have a narrow genetic base, our results show that sufficient polymorphism can be found among some arabica cultivars with a genetic similarity as low as 0.767 for genetic/QTL mapping and breeding. The assessment of genetic diversity among arabica cultivars provided the necessary information to estimate the potential for using marker-assisted breeding for coffee improvement.

GAS EXCHANGE, GROWTH, YIELD AND BEVERAGE QUALITY OF COFFEA ARABICA CULTIVARS GRAFTED ON TO C. CANEPHORA AND C. CONGENSIS

Gas exchange, leaf carbon isotope discrimination, growth, yield and beverage quality were evaluated for two Coffea arabica cultivars (Catuai and Mundo Novo), grafted on to C. canephora and C. congensis progenies growing in open fields. During the years 1994 to 1997, grafting resulted in an average increase in bean yield of 151 and 89% for Catuai and Mundo Novo respectively. As analysed by sensory analyses and by the ratio between the mono-isomers and di-isomers of caffeoylquinic acid, beverage quality of the C. arabica was not altered by grafting. Shoot growth was significantly greater in grafted plants, showing an increase of 52% in total leaf area compared with the non-grafted plants. Under conditions of water excess in the soil there was little difference in the transpiration and stomatal conductance rates between the grafted and non-grafted plants, but the net photosynthesis was higher in grafted plants. With an accentuated water deficit in the soil in the dry period, the grafted plants showed significantly higher transpiration and stomatal conductance rates than the non-grafted plants, and similar values to those of C. canephora. Carbon isotope discrimination was greater in the grafted plants, suggesting greater root hydraulic conductance. The results suggest that the better performance of the grafted plants during the dry period was due to the greater capacity of the root system of C. canephora to provide water to the shoot thereby maintaining greater gas exchange in the leaves and consequently a greater carbon gain.

Influence of coffee pruning on the severity of frost damage

Frost damages in a field experiment of pruning types and systems for the cultivars of Coffea arabica Catuaí and Mundo Novo, were evaluated at Londrina (23º22’S, 52º10´W), State of Parana, southern Brazil, during the winter of 1990 and 1994. Pruning types evaluated were ‘esqueletamento’ (cutting off all plagiotropic branches at 20-30 cm from the orthotropic branch), ‘decote’ (cutting off the orthotropic branch at 1.5 m and 2.0 m above ground) and ‘recepa’ (cutting off the orthotropic branch at 0.8 m above ground), performed on all rows and on alternate rows, and on different sections of the plant. Results indicated that frost damage could increase according to the type and height of pruning. The pruning type ‘esqueletamento’ and prunings at higher levels were more suitable for regions with frost risk. Under severe frost condition, pruning type did not affect the damage in anyone of the treatments evaluated.

Changes to the content of sugars, sugar alcohols, myo-inositol, carboxylic acids and inorganic anions in developing grains from different varieties of Robusta ( Coffea canephora) and Arabica ( C. arabica) coffees

Changes in concentration of mono- and oligosaccharides, sugar alcohols, myo-inositol, carboxylic acids and inorganic anions in coffee grains were analysed during grain development in three cultivars of Coffea arabica L (Arabica) and two of C. canephora L var. Robusta (Robusta) by high performance anion exchange chromatography coupled to pulsed electrochemical detection (HPAE-PED). The majority of the components analysed either decreased in concentration during the first half of the development period or accumulated steadily during the latter half of the period. The profiles are taken to indicate relationships between the perisperm, the principal tissue in the young grain and the endosperm during maturation. While most of the free sugar in the mature grain is accounted for by sucrose, fructose and glucose are both at higher concentrations in the perisperm. Considerable amounts of myo-inositol (3–4% dry weight (DW)) are found in young grains, while only the phosphorylated form phytic acid occurs in mature grains (0.3–0.6% DW). Quinic acid, which is present in very low amounts in mature endosperm, represents between 6 and 16% DW in young grains, this possibly being the major precursor pool for the high amounts of chlorogenic acids (5–10% DW) which are a characteristic of mature coffee grains. Of the other organic acids analysed, citric and malic acids are dominant in the mature grain, with higher concentrations in Arabica than Robusta. The results are discussed with respect to the potential implications for transport mechanisms in developing coffee grains and also the importance of the compounds analysed for industrial quality and flavour.

250 Using Leaf Area Devices (LADS) to Estimate Total Leaf Area of Coffee Plants

It is difficult to estimate the total leaf area of coffee plants with accuracy due to the large number of leaves and the high leaf density of the plant canopy. In 1996, on Maui, Hawaii, 98 leaves of various sizes were randomly collected for each of five cultivars of Coffea arabica L. The cultivars used were `Guadalupe', `Guatemalan', `Mokka', `Red Catuai', and `Yellow Caturra'. Leaf length, width, and area were measured. Seventy-five leaves were used to develop leaf area models, and the remaining leaves were used to test the accuracy of the models using a 1:1 line. We then developed leaf area devices (LADs), which were made of sheet plastic and shaped to resemble coffee leaves. There were three groups of areas in the leaf area devices, based on leaf sizes. Total leaf area (TLA) contained three components. Each component related to the mean leaf area (k) and the number of leaves (n) in that group. The model for the total leaf area was: TLA = k1n1 + k2n2 + k3n3, where k is a constant in each group. The estimation errors for the different cultivars ranged from 5.6% to 12.3% for 1-year-old plants (four cultivars) and from 1.9% to 7.8% for mature plants (five cultivars). By using the LADs and counting the number of leaves, we can obtain the total leaf area for coffee plants in the field.

ASPECTOS ESTRUTURAIS DE CAFEEIRO INFECTADO COM XYLELLA FASTIDIOSA

Estudaram-se as alterações anatômicas em folhas e caules de ramos de cafeeiros infectados com X. fastidiosa visando compreender as causas dos seus distúrbios fisiológicos. Analisaram-se amostras dos cultivares comerciais de Coffea arabica L. - Catuaí Vermelho IAC H 2077-25-81 e Mundo Novo 515-20 enxertados sobre a progênie IAC 2258 de C. canephora - e de Catuaí Vermelho IAC H 2077-25-81 sem enxertia (pé franco). As amostras foram coletadas no campo, no Núcleo Experimental de Campinas, IAC, em cafezais onde foi detectada a presença da bactéria. Analisou-se também a estrutura da folha e do caule de ramos com e sem sintomas visuais da bactéria, sendo estimada a porcentagem de obstrução dos vasos do xilema do caule. Os ramos infectados apresentaram um encurtamento dos entrenós e, com o agravamento da doença, senescência foliar precoce na sua base, resultando em pequeno número de folhas no ápice. O número e a posição dos ramos por indivíduo com tais sintomas variaram entre as plantas, sendo mais freqüentes na região basal. Esses ramos também mostraram pecíolos e área foliar reduzidos e frutos menores e agrupados, em vista de um encurtamento dos pedicelos e dos entrenós, além de uma deposição de "goma" nos vasos do xilema do caule, pecíolo e folha, assim como divisões celulares anormais no xilema, floema e córtex daquelas partes. As células do mesofilo das folhas afetadas apresentaram número reduzido de cloroplastos, associado a maior concentração de cristais de oxalato de cálcio. Sugere-se que a presença da bactéria esteja induzindo a senescência foliar que se relaciona a um ou mais fatores de estresse.

AVALIAÇÃO DE PROGÊNIES DERIVADAS DO HÍBRIDO DE TIMOR COM RESISTÊNCIA AO AGENTE DA FERRUGEM

A ferrugem alaranjada das folhas (Hemileia vastatrix Berk. & Br.) é a principal moléstia do cafeeiro (Coffea arabica) no Brasil. Numerosos híbridos portadores de fatores genéticos que conferem resistência às raças desse fungo foram sintetizados e testados no Centro de Investigação das Ferrugens do Cafeeiro (CIFC) em Oeiras, Portugal. Dentre esses híbridos, destacam-se os derivados do cruzamento entre as variedades Caturra Vermelho x Híbrido de Timor (CV x HT) e Vila Sarchi x Híbrido de Timor (VS x HT). A partir de 1968, progênies de Caturra Vermelho x Híbrido de Timor e Vila Sarchi x Híbrido de Timor foram enviadas pelo CIFC ao Instituto Agronômico e, posteriormente, a vários outros centros experimentais para fins de seleção. Em 1982, instalou-se no Centro Experimental de Campinas um experimento (EP299), contendo 30 progênies de CV x HT, 12 de VS x HT e 15 de `Catuaí', sendo 9 de `Catuaí Amarelo' e 6 de `Catuaí Vermelho'. Nenhum tratamento fitossanitário foi feito para controlar o agente da ferrugem. O mate-rial foi avaliado quanto à produção, colhendo-se as plantas individualmente em 1984-89, e quanto ao aspecto vegetativo associado à produção, maturação dos frutos, altura e diâmetro da copa e incidência da ferrugem. A progênie de Catuaí Vermelho LCH2077-2-5-81-2 foi utilizada como testemunha. Verificou-se a existência de alta correlação positiva entre todas as variáveis estudadas. Os tratamentos puderam ser classificados em dois grupos, segundo a análise em componentes principais (ACP). O primeiro grupo é representado pelas linhagens dos cultivares Catuaí Vermelho e Catuaí Amarelo e o segundo grupo, pelos derivados de CV x HT e VS x HT. As plantas pertencentes ao primeiro grupo são mais produtivas, têm maior índice de avaliação visual (IAV), são mais tardias e suscetíveis ao agente da ferrugem, são mais altas e apresentam maior diâmetro da copa do que as do segundo grupo. Material bastante promissor foi observado na população C2591-5 derivada de CV x HT, que além de produtivo apresenta resistência ao agente da ferrugem.

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

Objetivou-se, com o presente estudo, avaliar o comportamento de quatro progênies do cultivar Catuaí Amarelo e três do Catuaí Vermelho de Coffea arabica em relação aos cultivares Caturra Amarelo e Mundo Novo da mesma espécie, na Estação Experimental do Instituto Agronômico, em Pindorama. Analisaram-se a produção total e as produções acumuladas a cada dois anos e os valores de rendimento (relação café cereja/beneficiado), a peneira média, a porcentagem de frutos desprovidos de sementes (porcentagem de chochos), o tipo das sementes e o peso de cem sementes tipo chato (grãos normais). Os resultados da produção total em um período de dezoito anos consecutivos indicaram que a progênie de Catuaí Amarelo CH 2077-2-5-62 se revelou a mais produtiva, superando inclusive o padrão Mundo Novo. A linhagem de Caturra Amarelo (LC 476) apresentou as mais baixas produções. Analisando-se as produções acumuladas a cada dois anos e a total, verificou-se a possibilidade de uma avaliação precoce nesse material. As características de frutos e sementes analisadas forneceram valores considerados normais para um café de bom padrão, possibilitando a recomendação do plantio dos cultivares Catuaí Amarelo e Catuaí Vermelho na região nordeste do Estado de São Paulo.

Susceptibility to chilling of some central-African cultivars of Coffea arabica

Abstract This study was aimed at identifying cultivars of coffee plants with a low susceptibility to chilling, on the basis of laboratory measurements of various types of impairment in response to low temperature. The chilling susceptibility of nine central-African cultivars of Coffea arabica was determined using juvenile and adult potted plants. The above-ground parts were exposed for 12 h during the night to temperatures of +4°C. After rewarming, the changes in and recovery of both photosynthetic CO 2 uptake and the variable fluorescence of chlorophyll- a were measured and the extent of leaf necrosis recorded. All cultivars were damaged by the chilling stress, the juvenile plants clearly being more susceptible than the adults. However, statistically significant differences were found between the individual cultivars with respect to maximal depression and speed of recovery in photosynthetic activity and extent of leaf necrosis. No clear correlation could be shown between the various parameters measured. Therefore, an index for the susceptibility to chilling was calculated from the loss in photosynthetic productivity and the extent of necrosis. The resulting appraisal of the susceptibility of cultivars with a normal growth habit was in good agreement with recordings of survival after a cold spell in coffee plantations in Chipinge, Zimbabawe (relatively resistant: K7, SL28, K33; intermediate: Mundanova; most susceptible: Agaro, Geisha). The dwarf cultivars (Caturra, Red Catuai, Catuai Yellow) suffereds relatively more damage in the laboratory experiment than in plantations, where the plants were probably exposed to less-extreme temperatures on account of their low habit of growth.

Melhoramento do cafeeiro: XLII. Produtividade de progênies derivadas de hibridação dos cultivares Laurina e Mundo Novo

O cultivar Laurina de Coffea arabica L. caracteriza-se pelo pequeno porte, folhas de dimensões reduzidas, frutos afilados na base, sementes pequenas e afiladas, pequeno rendimento e reduzida produção. Apresenta, no entanto, bebida de boa qualidade e baixo teor de cafeína nas sementes. Suas principais características são controladas pela ação de um par de alelos recessivos lrlr, de acentuado efeito pleiotrópico. Devido ao atual interesse do comércio por produto de baixo teor de cafeína, iniciaram-se pesquisas tendo em vista principalmente aumentar a produtividade do 'Laurina'. Para esse fim, realizaram-se numerosas hibridações de cafeeiros do 'Laurina' com os do 'Mundo Novo' (Coffea arabica) e, posteriormente, retrocruzamentos com o 'Mundo Novo'. Estudaram-se as progênies F2 e retrocruzamentos com o 'Mundo Novo' (RC) em Campinas, em um experimento, anotando-se as produções por oito anos consecutivos. Separaram-se algumas progênies F2 em dois grupos, antes do plantio: normais (LrLr,Lrlr) e laurina (Irlr). Como testemunhas, usaram-se progênies do 'Mundo Novo' e 'Catuaí Amarelo' de C. arabica. O conjunto de plantas F2 do grupo laurina e os retrocruzamentos tiveram produção média maior do que as plantas F2 normais, porém menor do que as testemunhas. Alguns retrocruzamentos e progênies F2 apresentaram plantas com razoável produtividade, indicando que, através de retrocruzamentos com o 'Mundo Novo', podem-se obter novos tipos comerciais com as características morfológicas do 'Laurina'. Fizeram-se considerações sobre a melhor capacidade de combinação do 'Laurina' com algumas seleções do 'Mundo Novo'.