Validação de marcadores microssatélites e diversidade genética de genótipos de Coffea arabica provenientes da Etiópia.

O café é uma valiosa commodity agrícola, sendo sua bebida uma das mais populares do mundo. Apesar do sucesso dos programas de melhoramento em Coffea arabica, o desenvolvimento de novas cultivares é demorado, podendo levar mais de 20 anos. Além disso, a estreita base genética de C. arabica pode dificultar a obtenção de cultivares resistentes a pragas e a doenças ou tolerantes a estresses abióticos. Os acessos selvagens de C. arabica geneticamente distantes das variedades cultivadas proporcionam novos alelos para enriquecer sua variabilidade genética. O objetivo deste trabalho foi validar marcadores moleculares do tipo SSR em um painel de 24 acessos de C. arabica da coleção da Etiópia, realizar um estudo da diversidade , estrutura e seleção de genótipos Para futuros trabalhos de introgressão no melhoramento. Neste trabalho foram utilizados 58 marcadores microssatélites (SSR) obtidos de análises in silico a partir de dados de RNA-seq da cultivar Iapar 59 e de sequências de BACs de Hibrido de Timor 832/2, e 77 SSR obtidos de uma extensa revisão bibliográfica em C. arabica e/ou C. canephora. Dos 135 SSR utilizados, 122 resultaram em produtos de amplificação e 31 foram polimórficos no painel. Desses, 20 SSR foram altamente informativos com valores de PIC acima de 0,7, e sete são descritos pela primeira vez. Um total de 165 alelos foram obtidos com média de 5,3 alelos por loco. O estudo de diversidade e estrutura genética dos acessos separou os genótipos em três principais grupos. A utilização de marcadores SSR informativos assim como o estudo de diversidade e estrutura genética destes e dos demais acessos permitirá a criação de uma coleção nuclear, facilitando a conservação, acessibilidade e uso de recursos genéticos de cafeeiros da Etiópia

Protocolos para experimentação, identificação, coleta e envio de amostras da cigarrinha Dalbulus maidis e de plantas com enfezamentos em milho.

Diante do alto risco de ocorrência dos enfezamentos e da crescente demanda por padronização nas pesquisas que favoreçam o avanço de estratégias de manejo dos enfezamentos e controle eficiente da cigarrinha, este protocolo foi elaborado por pesquisadores da Embrapa com a colaboração Agropecuária do Paraná - ADAPAR. Quatro protocolos descrevem metodologias e recomendações para experimentação de campo, identificação de sintomas dos enfezamentos e da cigarrinha, identificação molecular dos patógenos, coletas, amostragem e envio de cigarrinhas e partes das plantas de milho para análises. Espera-se assim que as pesquisas ocorram de forma padronizada, fornecendo dados robustos que permitam o avanço de conhecimento baseado em critérios que favoreçam a elaboração de estratégias de manejo da cigarrinha e dos enfezamentos.bitstream/item/223514/1/Cartilha-Manejo-das-cigarrinhas-e-enfezamentos.pdfCartilha

Soluble sugars, enzymatic activities and gene expression during development of coffee fruits submitted to shade condition.

Effects of shade (50% light) condition on development and sugar metabolism was analyzed in fruits of Coffea arabica L. var. IAPAR 59. Fresh weight measurements of separated tissues (pericarp, perisperm and endosperm) showed that the increased size observed in beans of shaded plants was correlated with high perisperm development. Reducing sugar contents in the pericarp and endosperm of fruits from shaded plants appeared higher than in the same tissues of control (?full-sun?) plants. On the contrary, sucrose content was slightly lower in shade than in control beans. At the enzymatic level, sucrose synthase activities detected in the latest stages (197-231 DAF) of perisperm development from shaded plants were higher than from of control, confirming the importance of this tissue in coffee fruit development. At the molecular level, the CaSUS1 and CaSUS2 gene expression was also analyzed in the endosperm from control and shaded fruits. Expression level of CaSUS2 was higher in mature beans (260 DAF) of shaded plants than in control plants (231 DAF). These results showed that light condition affect sucrose metabolism of coffee beans

Population structure and genetic relationships between Ethiopian and Brazilian Coffea arabica genotypes revealed by SSR markers.

genotypes is highly relevant to optimize the use of genetic resources for breeding purposes. In this study, we evaluated genetic diversity, clustering analysis based on Jaccard?s coefficient and population structure in 33 genotypes of C. arabica and of three diploid Coffea species (C. canephora, C. eugenioides and C. racemosa) using 30 SSR markers. A total of 206 alleles were identified, with a mean of 6.9 over all loci. The set of SSR markers was able to discriminate all genotypes and revealed that Ethiopian accessions presented higher genetic diversity than commercial varieties. Population structure analysis indicated two genetic groups, one corresponding to Ethiopian accessions and another corresponding predominantly to commercial cultivars. Thirty-four private alleles were detected in the group of accessions collected from West side of Great Rift Valley. We observed a lower average genetic distance of the C. arabica genotypes in relation to C. eugenioides than C. canephora. Interestingly, commercial cultivars were genetically closer to C. eugenioides than C. canephora and C. racemosa. The great allelic richness observed in Ethiopian Arabica coffee, especially in Western group showed that these accessions can be potential source of new alleles to be explored by coffee breeding programs.Made available in DSpace on 2019-12-09T18:11:08Z (GMT). No. of bitstreams: 1 PopulationStructureandGenetic.pdf: 1219836 bytes, checksum: 4bb6b53cab12112c70e2b26787419f78 (MD5) Previous issue date: 2019bitstream/item/206427/1/Population-Structure-and-Genetic.pd

Population structure and genetic relationships between Ethiopian and Brazilian Coffea arabica genotypes revealed by SSR markers.

genotypes is highly relevant to optimize the use of genetic resources for breeding purposes. In this study, we evaluated genetic diversity, clustering analysis based on Jaccard?s coefficient and population structure in 33 genotypes of C. arabica and of three diploid Coffea species (C. canephora, C. eugenioides and C. racemosa) using 30 SSR markers. A total of 206 alleles were identified, with a mean of 6.9 over all loci. The set of SSR markers was able to discriminate all genotypes and revealed that Ethiopian accessions presented higher genetic diversity than commercial varieties. Population structure analysis indicated two genetic groups, one corresponding to Ethiopian accessions and another corresponding predominantly to commercial cultivars. Thirty-four private alleles were detected in the group of accessions collected from West side of Great Rift Valley. We observed a lower average genetic distance of the C. arabica genotypes in relation to C. eugenioides than C. canephora. Interestingly, commercial cultivars were genetically closer to C. eugenioides than C. canephora and C. racemosa. The great allelic richness observed in Ethiopian Arabica coffee, especially in Western group showed that these accessions can be potential source of new alleles to be explored by coffee breeding programs

Effects of shade on the development and sugar metabolism of coffee (Coffea arabica L.) fruits.

Coffee fruits grown in shade are characterized by larger bean size than those grown under full-sun conditions. The present study assessed the effects of shade on bean characteristics and sugar metabolism by analyzing tissue development, sugar contents, activities of sucrose metabolizing enzymes and expression of sucrose synthase-encoding genes in fruits of coffee (Coffea arabica L.) plants submitted to full-sun (FS) and shade (SH) conditions. Evolution of tissue fresh weights measured in fruits collected regularly from flowering to maturation indicated that this increase is due to greater development of the perisperm tissue in the shade. The effects of light regime on sucrose and reducing sugar (glucose and fructose) contents were studied in fresh and dry coffee beans. Shade led to a significant reduction in sucrose content and to an increase in reducing sugars. In pericarp and perisperm tissues, higher activities of sucrose synthase (EC 2.4.1.13) and sucrose-phosphate synthase (SPS: EC 2.4.1.14) were detected at maturation in the shade compared with full sun. These two enzymes also had higher peaks of activities in developing endosperm under shade than in full sun. It was also noted that shade modified the expression of SUS-encoding genes in coffee beans; CaSUS2 gene transcripts levels were higher in SH than in FS. As no sucrose increase accompanied these changes, this suggests that sucrose metabolism was redirected to other metabolic pathways that need to be identified.200

Crescimento inicial do cafeeiro Rubi em resposta a doses de nitrogênio, fósforo e potássio e a regimes hídricos Initial growth of Rubi coffee plant in response to nitrogen, phosphorus and potassium and water regimes

O objetivo deste trabalho foi avaliar o crescimento da parte aérea do cafeeiro (Coffea arabica L.) cultivar Rubi MG 1192 submetido a três doses de N, P e K e dois regimes hídricos durante o primeiro ano após o transplante, em 20 de novembro de 2000. O crescimento da planta foi avaliado aos 134, 196, 236, 284, 334 e 383 dias após o transplante (dat). Houve resposta ao N e ao K no crescimento em número de ramos plagiotrópicos por planta, ao passo que no número de nós com gemas por planta, observou-se resposta apenas ao nitrogênio. Não houve resposta ao N, P e K no aumento da massa seca da parte aérea e no índice de área foliar. Além de mostrar efeito significativo no crescimento do cafeeiro, a irrigação antecipou o rápido crescimento para julho (236 dat) proporcionando plantas mais vigorosas. Nas plantas não-irrigadas, o rápido crescimento ocorreu em meados de outubro (334 dat). Entretanto, a irrigação não impediu a queda na taxa de crescimento durante o inverno. O desenvolvimento das gemas em frutos ou ramos secundários nas plantas não-irrigadas alterou a distribuição de matéria seca e reduziu o crescimento do caule, ramos e folhas.<br>The objective of this work was to evaluate shoot growth of coffee trees (Coffea arabica L.) cultivar Rubi MG 1192 under three N, P and K doses and two water regimes during the first year after transplanting, starting on the 20th November 2000. The growth was evaluated at 134, 196, 236, 284, 334 and 383 days after transplanting (DAT). Nitrogen and K affected the number of plagiotropic branches per plant. Nevertheless, only N affected the number of nodes with axillary buds. There was no growth response to N, P, and K in terms of the total shoot dry mass and leaf area index during the experimental period. Irrigated treatments presented the best plant growth results, provided more vigorous plants and anticipated the fast growth phase to July (236 DAT), but could not avoid growth rate decrease during the winter. The fast plant growth phase of non-irrigated plants occurred by the middle of October (334 DAT); in these treatments, the development of buds into fruits or secondary branches altered the dry matter distribution and reduced stem, branches and leaves growth