Search

Recent outbreaks of Verticillium wilt diseases in various vegetable crops have been reported in Brazil. This fact was our initial stimulus to carry out a nationwide survey aiming to determine their causal agent(s). Thus far, Verticillium dahliae has been reported as the predominant species based solely on morphological traits. As other Verticillium species can be associated with wilt diseases, we characterized a collection of 80 isolates, collected across 10 agricultural Brazilian regions, by combining morphological, biological, and molecular traits. A multilocus approach was employed for identification of Verticillium species with information from three genomic regions (ribosomal internal transcribed spacer region, glyceraldehyde-3-phosphate dehydrogenase, and actin genes). Only 21 out of the 80 isolates were unable to produce microsclerotia in culture. The analyses of all genomic regions indicated V. dahliae as the sole species associated with vascular wilt of distinct hosts, including major solanaceous vegetables and other hosts such as trawberry, okra, and cacao. Pathogenicity tests confirmed the infection by the V. dahliae isolates and the development of typical disease symptoms on their original hosts. This is the first nationwide characterization of Verticillium isolates associated with major vegetable crops in Neotropical areas. This provides valuable information to design sound management strategies for these diseases, mainly for establishing efficient rotation systems and for the development of resistant cultivars. Made available in DSpace on 2022-07-10T04:00:32Z (GMT). No. of bitstreams: 1 Plant-Pathology-2022-Suaste8208Dzul-Verticillium-diseases-of-vegetable-crops-in-Brazil-Host-range-microsclerotia.pdf: 2203711 bytes, checksum: 174ffb030b398d1f1c1fc7fd72b1fe7f (MD5) Previous issue date: 2022

Septoria leaf spot is a severe disease of lettuce in tropical and subtropical regions, inducing yield/quality losses and increasing production costs. Globally, Septoria lactucae has been reported as the major pathogen associated with this disease. However, a complex of Septoria species has been also reported in association with lettuce crop around the world. Extensive surveys of Septoria species associated with this disease have not been conducted in the Neotropics. Therefore, the objective of the present study was to undergo a phenotypic and genetic characterization of a collection of 32 Brazilian Septoria isolates causing lettuce leaf spot. Morphometrical characterization of conidia and pycnidia was conducted with ten isolates obtained from three lettuce-producing regions in Brazil. In addition, partial sequences of four gene regions (β-tubulin, RPB2, actin, and calmodulin) were used in phylogenetic analyses of all 32 Septoria isolates. All tested isolates were pathogenic to two lettuce cultivars and morphometrically similar to each other. These isolates grouped together into a single monophyletic clade composed exclusively by genuine S. lactucae isolates. Therefore, S. lactucae was found to be the sole species associated with the Septoria leaf spot of lettuce in Brazil. The number of polymorphic sites (n = 27), mutations (n = 190), the level of nucleotide diversity (0.00262), and the average number of nucleotide differences (2.961) were relatively low. Notwithstanding, this genetic variability allowed the identification of 17 haplotypes amongst the 32 Brazilian isolates. This information will help to guide resistance breeding programs and establish more effective management strategies of this disease. Made available in DSpace on 2022-08-15T20:22:58Z (GMT). No. of bitstreams: 1 Cabral-et-al-2022-Journal-of-Plant-Diseasees-and-Protection-129-p-53-62-2022.pdf: 1727558 bytes, checksum: 5ea0e8c3e2f883bfc7a249e1f0b8f6c4 (MD5) Previous issue date: 2022

Reverse transcription-quantitative PCR (RT-qPCR) is an analytical tool for gene expression quantification. Reference genes are not yet available for gene expression analysis during interactions of Ralstonia solanacearum with ‘Hawaii 7996’ (the most stable source of resistance in tomato). Here, we carried out a multi-algorithm stability analysis of eight candidate reference genes during interactions of ‘Hawaii 7996’ with one incompatible/avirulent and two compatible/virulent (= resistance-breaking) bacterial isolates. Samples were taken at 24- and 96-h post-inoculation (HPI). Analyses were performed using the ∆∆Ct method and expression stability was estimated using BestKeeper, NormFinder, and geNorm algorithms. TIP41 and EF1α (with geNorm), TIP41 and ACT (with NormFinder), and UBI3 and TIP41 (with BestKeeper), were the best combinations for mRNA normalization in incompatible interactions at 24 HPI and 96 HPI. The most stable genes in global compatible and incompatible interactions at 24 HPI and 96 HPI were PDS and TIP41 (with geNorm), TIP41 and ACT (with NormFinder), and UBI3 and PDS/EXP (with BestKeeper). Global analyses on the basis of the three algorithms across 20 R. solanacearum-tomato experimental conditions identified UBI3, TIP41 and ACT as the best choices as reference tomato genes in this important pathosystem.

Aim Physiological race determination of 143 Fusarium oxysporum f. sp. lycopersici (FOL) isolates collected along 30 years in major tomato-producing regions of Brazil. Made available in DSpace on 2021-08-10T02:07:11Z (GMT). No. of bitstreams: 1 jam.14966.pdf: 573920 bytes, checksum: 929ad03882c7bfebc86e1a67aa04999d (MD5) Previous issue date: 2021

In a systematic field survey for plant-infecting viruses, leaf tissues were collected from trees showing virus-like symptoms in Brazil. After viral enrichment, total RNA was extracted and sequenced using the MiSeq platform (Illumina). Two nearly full-length picorna-like genomes of 9534 and 8158 nucleotides were found associated with Hovenia dulcis (Rhamnaceae family). Based upon their genomic information, specific primers were synthetized and used in RT-PCR assays to identify plants hosting the viral sequences. The larger contig was tentatively named as Hovenia dulcis-associated virus 1 (HDaV1), and it exhibited low nucleotide and amino acid identities with Picornavirales species. The smaller contig was related to insect-associated members of the Dicistroviridae family but exhibited a distinct genome organization with three non-overlapping open reading frames (ORFs), and it was tentatively named as Hovenia dulcis-associated virus 2 (HDaV2). Phylogenetic analysis using the amino acid sequence of RNA-dependent RNA polymerase (RdRp) revealed that HDaV1 and HDaV2 clustered in distinct groups, and both viruses were tentatively assigned as new members of the order Picornavirales. HDaV2 was assigned as a novel species in the Dicistroviridae family. The 5&prime, ends of both viruses are incomplete. In addition, a nucleotide composition analysis (NCA) revealed that HDaV1 and HDaV2 have similarities with invertebrate-infecting viruses, suggesting that the primary host(s) of these novel virus species remains to be discovered.

Made available in DSpace on 2020-12-17T09:02:43Z (GMT). No. of bitstreams: 1 viruses-12-00819-v2.pdf: 1225454 bytes, checksum: 3470370ee0837471d9b4357b8faf5448 (MD5) Previous issue date: 2020

Brazil and Argentina have a combined soybean area of 53.6 million hectares, which accounts for over half of the total global production. The soybean crop in South America extends from latitude 8&ndash, 10&deg, S to 32&ndash, 36&deg, S. Such a vast, almost contiguous area imposes a serious sanitary risk to the crop. Currently, the prevalence of anthracnose is increasing, with recurring reports of severe epidemics and expressive yield losses. Soybean anthracnose is mainly associated with Colletotrichum truncatum, although other Colletotrichum species have also been reported as causal agents of this disease. Knowledge about the morphological, cultural, and molecular variability of C. truncatum in South America is crucial for disease management. Here, we present data on the molecular, morphological, biological, cultural, and pathogenicity of C. truncatum isolates collected in Brazil and Argentina. Light microscopy and randomly-amplified polymorphic DNA (RAPD) analysis were used for estimating the variability of isolates. Colletotrichum truncatum displayed three types of conidiogenesis, viz. conidial formation from conidiogenous cells on hyphal extremities, in conidiomas in acervuli, and directly from fertile setae (a mechanism yet-unreported for C. truncatum). RAPD profiling was effective in revealing the genetic diversity among C. truncatum isolates. The intra-group similarity was greater among the Argentinian isolates when compared to the Brazilian group. Furthermore, the results indicated a strong correlation between geographical origin and molecular grouping, with the exclusive or semi-exclusive assembling of Brazilian and Argentinian isolates in distinct clades. Finally, a preliminary account of the reaction of soybean accessions to C. truncatum is also included.

Snap and common beans (Phaseolus vulgaris L.) are severely affected by Bean golden mosaic virus (BGMV) infection, so far the only begomovirus reported on these crops in Brazil (1). Samples of snap and common beans colonized by the whitefly Bemisia tabaci biotype B and displaying golden mosaic, chlorotic spots, and leaf distortion were collected in three production regions in Goiás State (Goianápolis, Luziânia, and Itaberaí) between 2003 and 2007. Total DNA extracted from leaf samples was used as template in PCR assays using universal primers targeting conserved regions of the DNA-A and DNA-B genomes (3). Begomovirus-specific amplicons were observed only with DNA template from symptomatic plants. Two single amplicons were observed for both genomic segments, indicating the presence of bipartite species in all samples. Sequence analysis of four isolates (named as GO-176, GO-260, GO-354, and GO-368) obtained from common bean samples indicated identity levels of approximately 95% with the DNA-A segment of BGMV (GenBank Accession No. FJ665283). However, the complete DNA-A sequence (GenBank Accession No. HM357459.1) of the GO-060 isolate (from a symptomatic snap bean plant collected in Goianápolis) displayed 76% identity with BGMV (GenBank Accession No. FJ665283) and 95% identity with the DNA-A of a Sida micrantha mosaic virus (SimMV) isolate (GenBank Accession No. EU908733.1) reported to be infecting okra (Abelmoschus esculentus L.) and 94.8% with a SimMV isolate reported to be infecting soybean (GenBank Accession No. FJ686693) in Brazil (2). Koch's postulates were fulfilled for the isolate GO-060 by inoculating a set of soybean and bean accessions via a biolistic approach. The ratio of positive PCR amplicons per total of inoculated plants were 15 of 16 for snap bean cv. Trepador, 9 of 10 for snap bean cv. Fartura, 18 of 24 for common bean cv. Olate Pinto, and 19 of 25 for common bean cv. Carioca. The isolate was also able to infect eight of nine soybean ‘Doko’ plants. Sequence analysis using symptomatic leaf samples (15 days after inoculation) confirmed SimMV as the causal agent. To our knowledge, this is the first report of a SimMV isolate infecting P. vulgaris. This virus is apparently fast expanding its host range from Malvaceae to Solanaceae species and leguminous hosts after the introduction of B. tabaci biotype B (2). More extensive surveys are necessary to access the current epidemiological importance of SimMV in both snap and common beans in Brazil. References: (1) J.C. Faria and D. P. Maxwell. Phytopathology 89:262, 1999. (2) F. R. Fernandes et al. Arch. Virol. 154:1567, 2009. (3) M. R. Rojas et al. Plant Dis. 77:340, 1993.

A survey of viral diseases was carried out during 2012 to 2013 in two major tomato (Solanum lycopersicum L.) producing regions in Uruguay (Salto and Canelones). Lower leaves of fruit-bearing plants were observed displaying yellowing and interveinal chlorosis under greenhouse conditions. The symptoms were similar to those associated with magnesium deficiency. However, the chlorosis displayed a tendency to move up affecting medial and apical leaves and prevailed even after supplementary magnesium applications to the soil, indicating potential infection by either Tomato chlorosis virus (ToCV) or Tomato infectious chlorosis virus (TICV) (3). Four leaf samples were collected from two sites in Canelones and 28 samples were collected from distinct commercial fields in Salto. Whiteflies (Bemisia tabaci biotype Q and Trialeurodes vaporariorum) were present in all sampling sites. Total RNA was extracted from symptomatic and healthy (control) plants and used for cDNA preparation with the HS-11/HS-12 primer pair followed by PCR amplification using the same primer pair. The 587-bp amplicon, corresponding to a highly conserved region of the heat shock protein (HSP-70) homolog gene reported in both TICV and ToCV genomes, was observed only in the symptomatic samples. These PCR products were then subjected to nested PCR using the ToCV specific primer pair (ToC-5/ToC-6) and TICV specific primer pair (TIC-3/TIC-4) (1). The expected 463-bp ToCV-specific amplicon was observed in all symptomatic plants but not in the healthy controls. The 223-bp amplicon corresponding to TICV was not observed in any sample, indicating the sole presence of ToCV. The amplicon of one Uruguayan ToCV isolate from Salto (named as CRS03) was purified and directly sequenced (GenBank KC626018). BLAST analysis revealed 99% identity of CRS03 with one Spanish isolate (AF233435.1) (2). Virus-free B. tabaci biotype Q adults were exposed to symptomatic plants infected with the CRS03 isolate for a 24-h period and then cage-confined with 10 healthy tomato plants (line ‘LT17’) for a 48-h period. Symptoms were reproduced in all tested plants after a 65-day period and ToCV infection was confirmed via PCR assays and by sequence analysis of the gel-purified amplicons. This is the first formal report of ToCV infecting tomatoes in Uruguay. Incidence of symptomatic plants in tomato crops varied from 30 to 100%, even under low whitefly pressure. Epidemiological information needs to be generated in order to evaluate the impact of ToCV in the fresh-market tomato yield and quality. References: (1) C. I. Dovas et al. Plant Dis. 86:1345, 2002. (2) G. Lozano et al. Arch. Virol. 151:581, 2006. (3) G. C. Wisler et al. Arch. Virol. 151:409, 2006.

The main objective of the present work was to evaluate a large Solanum (section Lycopersicon) germplasm (comprising nine species and one botanic variety) aiming to identify useful sources of resistance to M. enterolobii. Made available in DSpace on 2019-07-30T00:56:48Z (GMT). No. of bitstreams: 1 ArtigoHBSearchfoursourcesM.enterolobii20191.pdf: 719186 bytes, checksum: 152fb5e19b37b9cc7ddb324c1dc85925 (MD5) Previous issue date: 2019

Made available in DSpace on 2019-05-02T00:35:18Z (GMT). No. of bitstreams: 1 FONSECAPlantDiseasev103p7772019.pdf: 289683 bytes, checksum: b1286d112f280e88bbe1827e432c84b9 (MD5) Previous issue date: 2019

The objective of the present study was to evaluate the growth and development of seedlings, tomato hybrid ‘BRS Nagai’, in substrates containing different amendments of hydrogel NC-MMt. Made available in DSpace on 2019-08-02T01:14:24Z (GMT). No. of bitstreams: 1 18069991hb3702199.pdf: 561104 bytes, checksum: 11765eaa01ef3ab7924c65ce92d655a9 (MD5) Previous issue date: 2019

A new bipartite begomovirus (family Geminiviridae) was detected on cowpea (Vigna unguiculata) plants exhibiting bright golden mosaic symptoms on leaves under field conditions in Brazil. Complete consensus sequences of DNA-A and DNA-B components of an isolate of the virus (PE?088) were obtained by nanopore sequencing and confirmed by Sanger sequencing. The genome components presented the typical genomic organization of New World (NW) begomoviruses. Pairwise sequence comparisons revealed low levels of identity with other begomovirus species previously reported infecting cowpea around the world. Phylogenetic analysis using complete sequences of DNA-A components revealed that the closest relatives of PE?088 (85-87% nucleotide sequence identities) were three legume-infecting begomoviruses from Brazil: bean golden mosaic virus, macroptilium common mosaic virus and macroptilium yellow vein virus. According to the current classification criteria, PE?088 represents a new species in the genus Begomovirus, tentatively named as cowpea bright yellow mosaic virus (CoBYMV). Made available in DSpace on 2020-02-13T18:16:37Z (GMT). No. of bitstreams: 1 NanoporesequencingofanovelbipartiteNewWorldbegomovirusinfectingcowpea.2019.pdf: 698810 bytes, checksum: 04996c44ec3b021cc5633c257679e0b6 (MD5) Previous issue date: 2019

Made available in DSpace on 2019-02-23T00:33:41Z (GMT). No. of bitstreams: 1 estimateofnaturalcrosspollinationrateofcapsicumannuumusingacodominantmolecularmarkerassociatedwithfruitp.pdf: 501099 bytes, checksum: d5c55231d1f72edbe550d086a736a622 (MD5) Previous issue date: 2019-02-22 Na publicação: M.E.N. Fonseca, P.P. Silva.

RESUMO O cultivo de abóboras (Cucurbita moschata) e morangas (Cucurbita maxima) apresenta grande importância econômica e social no Brasil. Nas últimas décadas, a região do Brasil Central tem se consolidado como um polo emergente de cultivo e comercialização dessas hortaliças. Dentre as cultivares mais comercializadas no país se destaca o híbrido interespecífico conhecido como ‘Tetsukabuto’ ou ‘Cabotiá’ originado entre o cruzamento de uma linhagem feminina de C. maxima com uma linhagem masculina de C. moschata. O objetivo do trabalho foi avaliar o desempenho agronômico de híbridos experimentais interespecíficos tipo Tetsukabuto em condições do Planalto Central do Brasil por meio da avaliação direta e a correlação entre as características dos frutos. Foi avaliado um conjunto de 35 combinações híbridas interespecíficas (C. maxima x C. moschata), empregando como linhagem maternal elite a moranga CNPH 0739 que foi cruzada com uma coleção de 35 linhagens de abóboras. O experimento foi conduzido em condições de campo em Brasília-DF. Foram avaliados a produtividade total de frutos, o número de frutos por planta, massa média de frutos, comprimento e largura dos frutos, teor de sólidos solúveis, espessura da polpa e da casca dos frutos. O rendimento foi positivamente correlacionado com maior número de frutos por planta, maior massa, maior espessura de polpa e maior largura de frutos. Plantas com frutos de maior massa apresentaram menores teores de sólidos solúveis. O híbrido experimental CNPH 2377 destacou-se para as características avaliadas e apresentou alta produtividade de frutos com 21,98 t/ha, com peso médio acima de 3 kg, cerca de 4 frutos por planta, com polpa espessa (34,41 mm), casca fina (2,17 mm) e razoável teor de sólidos solúveis (17,01°Brix). Assim, a maior produtividade foi cerca de duas vezes superior àquela do híbrido Jabras (testemunha comercial). Neste contexto, os resultados, obtidos no presente experimento, indicam boas perspectivas no sentido de se obter materiais genéticos do segmento varietal Tetsukabuto, combinando características agronômicas de interesse e melhor aptidão para o cultivo no Brasil Central.

Made available in DSpace on 2019-05-02T00:34:50Z (GMT). No. of bitstreams: 1 DescriptionofGolovinomycesorontiiastheCausalAgentofLettuceLactucasativaPowderyMildewinBrazilPlantDisease.pdf: 579258 bytes, checksum: 3325fbc811be48c023780e56bd8cf9cc (MD5) Previous issue date: 2019

O cultivo comercial do maracujá é afetado por diversos problemas fitossanitários, os quais contribuem para quebras de produção e significativa redução da vida útil dos plantios. Em algumas situações, a incidência de doenças pode inviabilizar o cultivo do maracujá. Fontes de resistência a distintas doenças têm sido identificadas em acessos de espécies de Passiflora. Neste trabalho, buscou-se avaliar a diversidade genética de acessos de oito espécies silvestres (P. setacea, P. nitida, P. serratodigitata, P. caerulea, P. gibertii, P. odontophyla, P. edulis e P. coccinea) e de um híbrido interespecífico (P. setacea x P. coccinea), utilizando marcadores moleculares análogos a genes de resistência (RGAs). Verificou-se uma grande diversidade no perfil eletroforético de RGAs nos acessos de Passiflora, permitindo a anotação de 96 amplicons polimórficos entre, pelo menos, um par de acessos. Os níveis de dissimilaridade genética (calculados exclusivamente com os marcadores RGAs) variaram entre 0,40 e 0,89 nos acessos das espécies de Passiflora avaliadas. A análise de sequência de um subgrupo destes amplicons obtidos com primers RGAs indicou que estas bandas correspondem a regiões genômicas que contêm segmentos (motivos) com identidade aos encontrados em genes de resistência previamente caracterizados em outras espécies vegetais. Desta forma, os dados indicam a existência de um repertório variado de marcadores do tipo RGA em Passiflora que podem ser potencialmente úteis em sistemas de caracterização molecular de germoplasma e em programas de melhoramento genético visando à resistência a doenças nesta cultura. The commercial cultivation of passion fruit can be affected by many diseases, which might induce sever fruit yield losses and significant life cycle reduction of the crop. In some situations disease incidence can make the passion fruit production not economically viable. Sources of resistance against several pathogens have been identified in accessions of Passiflora germplasm. In the present research we evaluate by using RGAs ("resistance gene analogs") markers the genetic diversity of accessions belonging to eight wild species (P. setacea, P. nitida, P. serratodigitata, P. caerulea, P. gibertii, P. odontophyla, P. eduli, and P. coccinea) as well as one interspecific hybrid (P. setacea. x P. coccinea). A remarkable diversity was observed among the RGA eletrophoretic profiles of the accessions, allowing the annotation of 96 polymorphic amplicons able to discriminate at least one pair of accessions. The levels of genetic dissimilarity in this group of Passiflora accessions (using exclusively this collection of RGA markers) ranged from 0.40 to 0.89. The sequence analysis of a subgroup of RGA amplicons indicated that they correspond to genomic regions that encompass typical disease resistance gene motifs described in other plant species. Our results indicate a quite variable structural repertoire of RGA segments in Passiflora species with many of them being potentially useful as molecular markers for germplasm fingerprinting systems and also for assisted selection strategies in disease resistance breeding programs in this crop.

'Brasileirinha' é uma cultivar de abóbora (Cucurbita moschata) com frutos bicolores que foi desenvolvida com o objetivo de disponibilizar um produto diferenciado devido ao aspecto ornamental e a composição nutricional de seus frutos. Esta cultivar foi selecionada na geração F7, sendo obtida via cruzamentos convencionais entre um acesso de frutos bicolores, provavelmente devido à presença de um alelo do gene B, e a cultivar Mocinha (com frutos imaturos de cor verde uniforme). A característica peculiar da cultivar Brasileirinha é a produção de frutos com casca apresentando uma marcante coloração bicolor (coloração amarela na região proximal e verde na posição distal dos frutos). A polpa apresenta coloração amarela-esverdeada em frutos colhidos imaturos e, à medida que o fruto amadurece, intensifica-se uma coloração alaranjada. Beta-caroteno e luteína são os principais carotenóides presentes em frutos para consumo verde. Em frutos em completo estádio de maturação (polpa laranja intensa) verifica-se a acumulação de beta-caroteno e alfa-caroteno (precursores da vitamina A) em torno de 243 mg g-1. A cultivar Brasileirinha tem apresentado boa resistência de campo a diferentes raças de oídio (Podosphaera xanthii). Esta cultivar é preferencialmente recomendada para consumo como abobrinha verde (no estádio de fruto imaturo) e para fins ornamentais (frutos em todos os estádios). Uma opção é o uso de frutos jovens em conservas. A cultivar Brasileirinha é recomendada para plantio em todas as tradicionais regiões produtoras do país. O sistema de produção para esta cultivar tem sido o mesmo adotado para outros tipos de abóboras. 'Brasileirinha' is a squash (Cucurbita moschata) cultivar developed by Embrapa Vegetable Crops, with a appealing ornamental appearance and carotenoid composition of its fruits might provide raw material for the development of value-added products targeting new market niches. This cultivar is an F7 line obtained by conventional crosses between an accession with bicolor fruits, more likely due to the presence of an allele of the B gene, and cultivar Mocinha (with uniform green fruits). The presence of bicolor fruits is the peculiar characteristic of cultivar Brasileirinha. The proximal portion of the fruit skin has a bright yellow color, while the distal portion has an intense green color. The fruit flesh has a uniform light yellow (cream) color when harvested at the immature stage, whereas at the ripe stage its flesh is orange. Beta-carotene and lutein are the predominant carotenoids at the immature stage. In fully mature fruits, the predominant pigments are beta-carotene and alfa-carotene (two pro-vitamin A carotenoids), with average values reaching 243 mg g-1. Cultivar Brasileirinha displayed good levels of field resistance to distinct powdery mildew (Podosphaera xanthii) races. This cultivar is recommended for consumption at immature fruit stage, for ornamental purposes (all fruit stages) and it might also be suitable for pickles (young fruits). Cultivar Brasileirinha might be used in all the traditional squash-producing areas of Brazil. The cropping system recommended for this cultivar is the ordinarily used for squash production.

Um aspecto ainda pouco estudado, mas de grande relevância no processo produtivo de sementes de pimenta do tipo dedo de moça (Capsicum baccatum var. pendulum) é a determinação tanto da maturidade fisiológica quanto do momento mais adequado para a colheita. Neste contexto, o objetivo deste trabalho foi avaliar a qualidade fisiológica de sementes de pimenta da espécie C. baccatum var. pendulum obtidas de frutos em diferentes estádios de maturação. O experimento foi realizado nas instalações do campo experimental e laboratórios de sementes e de pós-colheita da Embrapa Hortaliças, Brasília-DF. Para a determinação da maturidade fisiológica foi utilizada a cultivar BRS Mari. As sementes foram obtidas de frutos colhidos em diferentes estádios de maturação (20, 30, 40, 50, 60, 70 e 80 dias após antese). Foram determinados a coloração dos frutos, comprimento longitudinal, teor de clorofila e de capsaicina. Nas sementes, foram determinados o teor de água, a massa de 100 sementes, a germinação, a emergência de plântulas em casa de vegetação e o vigor, estimado pela primeira contagem de germinação e teste de envelhecimento acelerado. Foi utilizado o delineamento inteiramente casualizado. A maturidade fisiológica das sementes ocorreu aos 70 dias após a antese, onde os frutos apresentavam coloração vermelha, teores mínimos de clorofila e maiores picos de capsaicina. Neste estádio, as sementes apresentam valores máximos de germinação, vigor e matéria seca e teor de água de 39%. The determination of the physiological seed maturity as well as the most appropriate harvest time are important aspects to achieve high quality seeds. This information is still not available for seed production of "dedo de moça" pepper (Capsicum baccatum var. pendulum) accessions. Thus the objective of the present study was to evaluate the physiological seed quality of C. baccatum var. pendulum cv. BRS Mari from fruits harvested in different physiological maturity stages. The experiment was carried out at the experimental field and laboratories at Embrapa Hortaliças in Brasília Brazil. Seeds were obtained from fruits harvested at different maturation stages (20, 30, 40, 50, 60, 70 and 80 days after anthesis). We determined fruit color length chlorophyll and capsaicin contents seed moisture content 100 seed weight germination seedling emergence under greenhouse conditions and accelerated aging test. A completely randomized design (CRD) was used in this study. Physiological seed maturity of 'BRS Mari' occurred at 70 days after anthesis when fruits presented red color lower chlorophyll content and highest capsaicin accumulation. At this stage seed moisture content was 39% and the seed mass germination and vigor were the highest

A murcha-bacteriana causada por Ralstonia solanacearum é uma das principais doenças das solanáceas em climas tropicais. Historicamente limitante à produção de tomate na Região Norte do Brasil, passou a ser uma séria ameaça ao tomateiro também nas Regiões Sul e Sudeste após a expansão do cultivo protegido. Embora fontes de resistência à doença tenham sido identificadas em germoplasma de tomateiro, cultivares comerciais resistentes ainda não estão disponíveis no mercado. O uso de porta-enxerto comerciais de tomate tem se popularizado pelo fato de, além de proteger a planta contra a doença, reduzir o problema de incompatibilidade associada ao uso de espécies/gêneros diferentes. O objetivo deste trabalho foi avaliar, em casa de vegetação, os níveis de resistência à murcha bacteriana dos principais porta-enxertos comerciais de tomateiro, levando em conta a variabilidade patogênica de um conjunto de isolados de R. solanacearum. Foi observada uma clara distinção na incidência da doença entre os genótipos, e a reação foi do tipo isolado-dependente. Os porta-enxertos mais resistentes foram os híbridos 'Muralha' e 'Guardião', que não diferiram, para a maioria dos isolados, da linhagem 'Hawaii 7996' (padrão internacional de resistência) e apresentaram comportamento superior em relação aos híbridos 'Magnet' e 'Protetor'. Entretanto, todos os porta-enxertos avaliados sucumbiram à alta virulência do isolado CNPH 488 (Raça 1 / Biovar 2, coletado no estado do Paraná), que provocou a morte da totalidade das plantas. Quando avaliados em solo artificialmente infestado, com menor pressão de inóculo, 'Guardião' e 'Muralha' apresentaram, novamente, um desempenho significativamente superior ao de outros porta-enxertos. Os resultados obtidos reforçam que alguns porta-enxertos oferecem boa proteção do tomateiro contra a murcha-bacteriana sob condições normais de cultivo. Entretanto, em condições ambientais muito favoráveis à doença e/ou na presença de isolados muito virulentos, dificilmente o sistema de enxertia de tomateiro em tomateiro per se protegerá adequadamente a planta enxertada. Tal cenário exige medidas complementares e antecipadas de controle que visem a reduzir a população de R. solanacearum no solo ou escolha de ambiente menos propício à sua multiplicação. Bacterial wilt, caused by Ralstonia solanacearum, is one of the main diseases of solanaceous crops in Tropical regions, being the major limiting factor for tomato production in the North Region of Brazil. The disease has also been a constraint to tomato production under protected cultivation, which had solid expansion in the South and Southeast regions in the last decades. Although sources of resistance to bacterial wilt have been identified in S. lycopersicum germplasm, no resistant cultivars are available to growers. However, commercial rootstocks are available to protect scions against the disease, thus reducing the incompatibility associated to the use of different Solanaceae species/genera. The main objective of the present work was to evaluate the levels of resistance of a group of commercial hybrid/inbred tomato rootstocks to a diverse array of five R. solanacearum isolates (all obtained from infected tomato plants). A clear discrimination was observed among the evaluated rootstocks in relation to disease incidence. The phenotypic reaction of the tomato rootstocks was isolate-specific. The tomato hybrids 'Muralha' and 'Guardião' and the inbred line 'Hawaii 7996' (international resistance standard) were the rootstocks with best performance against the majority of the five R. solanacearum isolates, displaying significantly better resistance when compared with the hybrids 'Magnet' and 'Protetor'. However, all rootstocks were highly susceptible (100% mortality) to the R. solanacearum CNPH 488 isolate (classified as race 1 / Biovar 2, collected in Paraná State, Brazil). The same set of rootstocks was also evaluated under artificially infested soil (with less intense inoculum pressure). The hybrids 'Guardião' and 'Muralha' repeated their good performance when compared with 'Magnet' and 'Protetor'. Our results reinforce the notion that under favorable environmental conditions and/or in the presence of highly virulent strains, the system based upon tomato scion grafted onto tomato rootstock might provide unsatisfactory levels of bacterial wilt control. Therefore, complementary and preemptive control measures will be necessary in order to reduce the initial inoculum pressure in the soil.

O presente trabalho teve o objetivo de estimar o potencial de cultivo de grão de bico quando submetido a regime de baixa umidade no solo (sequeiro) e identificar genótipos com melhores características morfoagronômicas e de rendimento.

Cowpea crop, through combining a range of essential minerals with high quality proteins, plays an important role in providing nutritional security to human population living in semi-arid regions. Studies on genetics of biofortification with essential minerals are still quite scarce, and the major objective of the present study was to provide genetic information on development of cowpea cultivars with high seed mineral contents. Genetic parameters heritability and minimum number of genes were estimated for seed accumulation of zinc (Zn), iron (Fe), calcium (Ca), phosphorus (P), potassium (K), and sodium (Na). Generation mean and variance analyses were conducted using contrasting parental lines, F1, F2, and backcross populations derived from IT97K-1042-3 x BRS Tapaihum and IT97K-1042-3 x Canapu crosses. High narrow-sense heritability (h2) values were found for accumulation of Fe (65-86%), P (74-77%), and K (77-88%), whereas moderate h2 values were observed for accumulation of Ca (41-56%), Zn (51-83%), and Na (50-55%) in seeds. Significant additive genetic effects as well whereas epistasis was important genetic component in Zn content. The minimum number of genes controlling the accumulation of minerals ranged from two (K) to 11 (P). Transgressive segregation was observed in F2 populations of both crosses for all minerals analyzed. The results suggest that, although under either oligogenic or polygenic control, the seed content of these six minerals in cowpea can be improved via standard breeding methods largely used for self-pollinated crops. Made available in DSpace on 2018-01-12T23:14:00Z (GMT). No. of bitstreams: 1 gmr5063Boiteux9.pdf: 371839 bytes, checksum: f215bad515580b4f95de73d8f9ecfc82 (MD5) Previous issue date: 2015-12-01

The tomato yellow leaf curl disease (TYLCD) causes severe damage to tomato (Solanum lycopersicum L.) crops throughout tropical and subtropical regions of the world. TYLCD is associated with a complex of single-stranded circular DNA plant viruses of the genus Begomovirus (family Geminiviridae) transmitted by the whitefy Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae). The tomato inbred line TX 468-RG is a source of monogenic recessive resistance to begomoviruses derived from the hybrid cv. Tyking F1. A detailed analysis of this germplasm source against tomato yellow leaf curl virus-Israel (TYLCV-IL), a widespread TYLCD-associated virus, showed a significant restriction to systemic virus accumulation even under continuous virus supply. The resistance was effective in limiting the onset of TYLCV-IL in tomato, as significantly lower primary spread of the virus occurred in resistant plants. Also, even if a limited number of resistant plants could result infected, they were less efficient virus sources for secondary spread owing to the impaired TYLCV-IL accumulation. Therefore, the incorporation of this resistance into breeding programs might help TYLCD management by drastically limiting TYLCV-IL spread. © 2015 by the authors; licensee MDPI, Basel, Switzerland., This work was supported by grant AGL2013-48913-C2-1 from the Ministerio de Economia y Competitividad (MINECO) with assistance from the European Regional Development Fund (FEDER), Bilateral CSIC-CNPq project 2011BR0035, and agreement MINECO-CSIC RECUPERA 2020 financed by FEDER. We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI).

In the present work, we report for the first time the occurence of M. enterolobii infecting Capsicum annuumplants carrying the Me1 and Me3/Me7 genes under plastic house systems in Brasília-DF (Central Brazil).

Crinivírus, transmitidos por mosca-branca, engrossam a lista de viroses enfrentadas pelos produtores de tomate no Brasil e se somam a desafios como a incidência de Begomovírus e Tospovírus. A busca por cultivares resistentes tem se mostrado indispensável diante da ampla gama de hospedeiros e das limitações no controle do inseto-vetor.

Carrot powdery mildew was first detected in seed production fields of the cultivar Brasília in Brasília-DF in 2008. White cottony growth was observed on leaves, petioles, and floral stalks. In 2014 to 2016, powdery mildew outbreaks were observed (100% incidence) in carrot fields in Brasília-DF, São Gotardo-MG, São Miguel Arcanjo-SP, and Cristalina-GO. Made available in DSpace on 2017-10-14T10:32:38Z (GMT). No. of bitstreams: 1 Diseasesnotes.pdf: 457807 bytes, checksum: 25ce0da729061c7aa084ec73afbe48f0 (MD5) Previous issue date: 2017-10-13

Advances in tomato breeding for pest resistance have been achieved via gene introgression from wild Solanum (section Lycopersicon) species (Solanaceae). Ninety-nine F3 families derived from an interspecific cross using as parental lines Solanum lycopersicum L. ‘LAM-148’ (susceptible standard) and Solanum pimpinellifolium L. ‘TO-937-15’ (multiple pest resistance accession with type IV glandular trichomes and acylsugar accumulation) were evaluated for their resistance against the whitefly Bemisiatabaci(Gennadius)(Hemiptera:Aleyrodidae)biotypeBinfree-choiceandno-choicetestsforoviposition and adult colonization. The parental lines and eight F3 families with contrasting levels of resistance against the whitefly were selected and investigated in additional assays, which included the estimation of trichome densities and foliar acylsugar levels. The F3 families BTR-302 and BTR-331 exhibited low amounts of eggs of whitefly and transgressive segregation for type IV glandular trichome density with values greater than that of TO-937-15 plants. However, the tested families did not surpass the total foliar acylsugar content found in TO-937-15. BTR-331 exhibited low colonization in the free-choice test and it was the least preferred F3 family in the no-choice test. The higher resistance levels of BTR-331 were associated with a positive combination of higher type IV trichome density and higher acylsugar levels. Some F3 families displayed reduced fruit set due to the presence offlowerswithstyleexertionoftheantheridial-cone.Fruit weightat harvest stageoftheselectedfamilies (from 4.9 to 14.5 g) was lower than that of LAM-148 (139.5 g) but higher than that of TO-93715 plants (1.3 g). Therefore, although difficult to reach due to the simultaneous segregation of many polygenic traits, the combination of high B. tabaci resistance levels with superior horticultural traits is feasible. These results confirm TO-937-15 as a source of biotype B resistance. From the breeding standpoint, the genetic similarity between S. lycopersicum and S. pimpinellifolium would allow a more efficient resistance introgression by facilitating recombination and minimizing the potentially undesirablelinkagedragassociatedwiththistrait.

Leonurus sibiricus L. (Lamiaceae) is a subtropical weed frequently found with golden mosaic symptoms. Leonurus mosaic virus (LeMV) was the first begomovirus reported on L. sibiricus in Brazil (3). Later, a new bipartite species (Tomato yellow spot virus, ToYSV) was reported affecting tomatoes, beans, and also L. sibiricus (1,2). A survey of begomovirus isolates was conducted within tomato fields also displaying high incidence of plants with begomovirus-induced symptoms. Thirty L. sibiricus and 33 tomato samples were collected (2007 to 2012) in nine districts in Paraná State, Brazil. Two L. sibiricus isolates were also obtained within citrus orchards in Major Otaño, Itapúa, Paraguay. Total DNA was extracted from all 65 isolates and PCR assays were conducted with primers for conserved DNA-A (PAL1v1978/PAR1c496) and DNA-B (PBL1v2040/PCRc1) regions (3). Nucleotide sequence identity of the 1,193-bp DNA-A amplicons of our L. sibiricus isolates ranged from 93.4 to 98.2% with LeMV (GenBank Accession No. U925321) and from 92.4 to 94.8% with ToYSV isolates from tomato (DQ336350.1) and bean (FJ538207). None of the 33 tomato samples was found to be infected by ToYSV, with all having high nucleotide sequence identity (92 to 99%) only with Tomato severe rugose virus (GU358449). Complete DNA-A genome sequence was obtained via a rolling circle amplification-based strategy for one Brazilian L. sibiricus isolate (PR-088) and one isolate from Paraguay (PAR-07). The entire DNA-A genome of PR-088 (JQ429791) had 96.8% nucleotide sequence identity with PAR-07 (KC683374) and ranged from 95.6 to 96.3% with ToYSV isolates from bean, tomato, and L. sibiricus (JX513952). The nucleotide sequence identity of the 487-bp DNA-B amplicon ranged from 87 to 92% among PR-088 (KC 683374); PAR-07 (KC740619) and ToYSV isolates from tomato (DQ336351.1) and L. sibiricus (JX513953.1). Leonurus cuttings infected with the ToYSV (PR-088) were caged together with healthy L. sibiricus and tomato ‘Alambra’ seedlings. Hybridization assays with ToYSV-specific probes (2) and sequencing of PCR amplicons indicated that Bemisia tabaci biotype B adults were able to transmit ToYSV to both hosts as reported (1). Our results suggest that L. sibiricus is the main ToYSV reservoir under natural conditions and tomato seems to be an occasional alternative host. In fact, ToYSV has not often detected in tomatoes as observed in a number of extensive surveys (4). So far, the complete LeMV genome is not available for comparison (3). However, our analyses with a DNA-A segment indicated that LeMV and ToYSV isolates might represent strains of single virus at the current threshold of 89% nucleotide sequence identity for Begomovirus species discrimination (4). Thus, a reappraisal of the taxonomic status of ToYSV is necessary to clarify its genetic relationship with LeMV. This is the first report of ToYSV on L. sibiricus in Paraguay. References: (1) J. C. Barbosa et al. Plant Dis. 97:289, 2013. (2) R. F. Calegario et al. Pesq. Agrop. Bras. 42:1335, 2007. (3) J. C. Faria and D. P. Maxwell, Phytopathology 89:262, 1999. (4) F. R. Fernandes et al. Virus Genes 36:251, 2008.

O objetivo deste estudo foi comparar as performances dos híbridos pré-comerciais (HPCE) e híbridos novos (HNE) de melão ?Pele de Sapo‟ do programa de melhoramento da EMBRAPA com os híbridos comerciais (HC) mais plantados na região do Semiárido nordestino. Suplemento. Edição dos Anais do 53 Congresso Brasileiro de Olericultura, jul. 2014.

O objetivo do presente trabalho foi avaliar o efeito da aplicação foliar de nutrientes, diluidos em diferentes matrizes, na severidade dos sintomas de infecção viral, na produtividade toatal e comercial de tomateiro infectado por begomovirus, bem como no potencial germinativo de suas sementes.

Made available in DSpace on 2014-03-19T23:27:36Z (GMT). No. of bitstreams: 1 c8eb9792af792653.pdf: 558351 bytes, checksum: b1ba8ea9a9c261b161bdf9789309e4c2 (MD5) Previous issue date: 2014-03-19

One strategy to mitigate human malnutrition in semi-arid areas is to increase the protein and mineral content of cowpea cultivars. Total seed protein, potassium, calcium, iron, zinc, and sodium contents were quantified in elite cowpea lines, with the aim to develop cultivars that had improved levels of these nutrients. Eighty-seven F6 lines derived from 6 crosses were evaluated under rain-fed conditions in Petrolina, Brazil. Seed protein and mineral content were quantified by the micro-Kjeldhal method and in an atomic absorption spectrophotometer, respectively. Statistical analyses were estimated for all traits, including grain yield. Significant differences were observed for all characteristics. Seed protein content ranged from 22.5 to 34.1%, potassium levels ranged from 20,200 to 27,000 ppm, and calcium levels ranged from 410 to 6260 ppm. Iron content ranged from 36.5 to 137 ppm, while zinc content ranged from 36 to 58 ppm and sodium content ranged from 29.2 to 88 ppm. Simple correlation coefficient values indicated that selection for high protein and mineral content does not affect grain yield. These results demonstrate that it higher levels of protein and essential minerals. Made available in DSpace on 2014-03-18T23:33:44Z (GMT). No. of bitstreams: 1 GMR124678267892013.pdf: 308919 bytes, checksum: a07e7766a9c23181c7edd790612b7d86 (MD5) Previous issue date: 2014-03-18

No presente trabalho avaliou-se a produção e a qualidade de sementes híbridas de berinjela oriundas de plantas com diferentes números de frutos por planta, fecundados artificialmente.

Os objetivos deste trabalho foram: 1. verificar a possibilidade da utilização do efeito diretoda analise de trilha em substituição à correlação genética nas estimativas de ganhos correlacionados; 2. identificar estratégias de seleção para a obtenção de ganhos correlacionados em massa de raiz a seleção de raízes mais grossas ou mais compridas; 3. determinar quais tecidos da raiz possibilitam maiores ganhos para o aumneto do diâmetro da raiz; e 4. verificar a possibilidade de obter ganhos positivos concomitantemente, para coloração da raiz e para os demais caracteres avaliados.

Wild radish (Raphanus sativus L. and R. raphanistrum L.) and garden rocket [Eruca sativa (Mill) Thell] plants displaying interveinal yellowing in the lower leaves were found in Mauá da Serra (Paraná State, Brazil). The garden rocket field with symptomatic plants was in close vicinity to tomato (Solanum lycopersicum L.) fields with high frequency of plants displaying symptoms similar to that induced by the Crinivirus (Closteroviridae) species Tomato chlorosis virus (ToCV) and Tomato12 infectious chlorosis virus (TICV). Made available in DSpace on 2018-10-24T00:35:31Z (GMT). No. of bitstreams: 1 apsjournals.apsnet.orgWildRadishRaphanussppandGardenRocketErucasativaasNewBrassicaceaeHostsofTomatochlorosis.pdf: 178119 bytes, checksum: 4c296fd34c1eac74e8b27747bb24cfa8 (MD5) Previous issue date: 2015-12-01

O presente trabalho visou identificar os tipos citoplasmáticos de acessos de cebola de diferentes grupos morfoagronômicos de interesse para o melhoramento genético no Brasil, usando a ração da polimerase em cadeia (PCR) com primers específicos para regiões polimórficas do genoma mitocondrial de cebola.

O objetivo do trabalho foi identificar marcadores RAPD para utilização em sistemas de seleção assistida do locus Ty-1. Made available in DSpace on 2013-01-02T23:02:35Z (GMT). No. of bitstreams: 1 Fito201245Congress131.pdf: 98334 bytes, checksum: ec8a384af1c756b2a9b750367ead2c5f (MD5) Previous issue date: 2013-01-02

O objetivo do trabalho foi avaliar o efeito do locus Ty-1 quando em homozigose, heterozigose e ausente em plantas inoculadas com um isolado de Tomato severe rugose virus via moscas brancas viruliferas.

Setenta e quatro progênies meio-irmãs derivadas de 'Alvoradas' foram avaliadas durante o verão de 2005 no Distrito Federal (DF), em blocos casualizados com três repetições. Made available in DSpace on 2018-04-10T00:38:13Z (GMT). No. of bitstreams: 1 HBv30n1a02.pdf: 722521 bytes, checksum: 653761ac365a8730753b51858f955d17 (MD5) Previous issue date: 2012-05-04

Made available in DSpace on 2018-05-30T00:56:56Z (GMT). No. of bitstreams: 1 a19v28n2.pdf: 1308227 bytes, checksum: 155c2c8839c7e060865f2f237854a25f (MD5) Previous issue date: 2010-08-16