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Organic farming requires the production or use of certified seeds from the same cultivation system and, the information of potato cultivars adapted to organic production system is important. The objective of this work was to study the feasibility of utilizing sprouts of different potato cultivars, seed multiplication and yield potential in field conditions without using agrochemicals. Three experiments were conducted: the first experiment using sprouts as seed under protected cultivation in Guarapuava, Paraná State, Brazil, from November 2011 to February 2012; the second experiment was field conducted in Candói, Paraná State, from May to September 2012 and the third experiment was field conducted in Guarapuava, Paraná State, from February to May 2013. The experimental design was a randomized block design with 3 replications in all 3 experiments. In the 2 first experiments the following cultivars were evaluated: BRS Ana, BRS Clara, BRS Eliza, Crystal and Catucha, and in the last experiment Agata, Bintje, Baronesa and BRSIPR Bel were included. The traits analyzed were length of main stem, number of stems, number of leaves, fresh weight and number of tubers, percentage of infection by viruses and in the second experiment the incidence of late blight on leaves. In the third experiment, leaf area index (LAI), tuber, leaves and stem dry weights and late blight severity were also analyzed. In the first experiment, the cultivars showed differences in plant height and minituber production, the highest value was observed in cultivars BRS Clara and BRS Ana for plant height and cultivar BRS Clara for minituber production. In the second experiment, there was difference only in plant height, the tallest cultivars were BRS Ana and BRS Clara . There was low spread of viruses and, it did not directly reflect in tuber yield. In the third experiment the cultivars with lower disease severity were those recommended to organic farming, especially BRS Clara and Catucha; this second cultivar had the higher LAI and tuber yield, as well as resistance to late blight, factors that might have contributed to the recorded highest total tuber yield (13.8 t/ha). RESUMO O cultivo orgânico demanda a produção ou aquisição de sementes ou mudas certificadas a partir do mesmo sistema de cultivo, sendo imprescindível o estudo de cultivares de batata adaptadas ao sistema orgânico de produção. O objetivo deste trabalho foi estudar a viabilidade do aproveitamento de brotos de cultivares de batata, a multiplicação de sementes no campo e a produção comercial sem utilização de agroquímicos. Conduziu-se três experimentos, o primeiro sob cultivo protegido em Guarapuava-PR, de novembro de 2011 a fevereiro de 2012, o segundo em campo em Candói-PR, de maio a setembro de 2012, e o último em campo em Guarapuava-PR, de fevereiro a maio de 2013. O delineamento experimental foi de blocos casualizados com 3 repetições nos 3 experimentos. Avaliou-se nos 2 primeiros experimentos as cultivares: BRS Ana , BRS Clara , BRS Eliza , Cristal e Catucha e no último foram adicionados Agata , Bintje , Baronesa e BRSIPR Bel . As características analisadas foram: comprimento de haste principal, número de hastes, número de folhas, massa fresca e número de tubérculos, porcentagem de infecção por viroses, além de incidência de requeima nas folhas no segundo experimento, e no terceiro experimento ainda foi analisado, índice de área foliar (IAF), massa seca de tubérculos, folhas e hastes e severidade de requeima. No primeiro experimento as cultivares demonstraram diferença na altura de plantas e produção de minitubérculos, sendo a maior média observada nas cultivares BRS Ana e BRS Clara em altura de planta, e na cultivar BRS Clara na produção de minitubérculos. No segundo experimento houve diferença apenas na altura de plantas, com maior média final observada nas cultivares BRS Ana e BRS Clara. Observou-se baixa disseminação de viroses e isto não refletiu diretamente na produtividade. No terceiro experimento as cultivares com menor severidade de doença foram as indicadas para cultivo orgânico, em especial a BRS Clara e a Catucha ; esta segunda se destacou em IAF e produtividade, e demonstrou alta resistência à requeima, principal motivo que levou esta cultivar a atingir 13,8 t/ha de produtividade total.

Over the past 10 years, Tomato yellow vein streak virus (ToYVSV) has been a major begomovirus in the main solanaceous crop region of Campinas, São Paulo, which includes counties of Sumaré, Monte Mor, Elias Fausto, and Indaiatuba. The top leaves of potato plants (Solanum tuberosum) having deforming mosaic symptoms (dms), which includes a yellow mosaic or mottling on distorted and deformed leaflets, were associated with this geminivirus (4). Recently, a table potato crop (cv. Agata) from Sumaré, with a record of a few or no white flies (Bemisia tabaci), during the winter season of June to September 2006 had 5 to 7% dms, suggestive of seed potato tuber borne virus infection. Double-antibody sandwich (DAS)-ELISA for Potato virus Y (PVY), Potato leaf roll virus (PLRV), Potato virus X (PVX), and Potato virus S (PVS) (SASA kits and protocols, Edinburgh, Scotland) gave negative results for four field collected potato plants showing dms. Bioassays (mechanical transmission from potato leaf extracts in phosphate buffered saline, 1:5 w/v) with test plants of Nicotiana tabaccum cvs. Turkish and TNN, Gomphrena globosa, Chenopodium quinoa, Datura metel, Solanum tuberosum, and a Physalis sp. were all negative. Inoculated D. stramonium developed symptoms resembling ToYVSV infection including vein clearing and mild mottling on new leaves 2 to 3 weeks postinoculation. Using primers PAC1v1978/PAV1c715 for begomovirus detection (3), the predicted PCR amplified fragment of 1,320 bp was obtained from leaf DNA extracted from all four of the dms field potato plants, as well as the inoculated and symptomatic D. stramoniium test plants. Sequence analysis indicated 100% nt identity among the 1.3-kb PCR fragments obtained from potato and D. stramonium infected plants. Sequences of 96 cloned amplicons (pGEM-T Easy Kit; Promega, Madison, WI) from symptomatic plants in the Sumaré potato field were 98 to 99% identical to Tomato severe rugose virus (ToSRV). BLAST analysis of a consensus sequence (Sequencher 3.1; Gene Codes Corporation, Ann Arbor, MI) revealed more than 95 and 99% identity with ToSRV isolates from Uberlandia (Accession No. AY029750) and Goias (Accession No. DQ207749), respectively. The DNA-based phylogenetic dendrogram confirmed the highest similarity with ToSRV and the lowest similarity with ToYVSV (72%), which was located in another cluster. These results indicate that ToSRV was the causal agent producing dms in potato plants from Sumaré. Therefore, similarly to ToYVSV (4), potato dms can be caused by ToSRV. Preliminary tests revealed that ToSRV was transmitted via seed tubers. Thus, it is of concern for seed potato certification in Brazil, especially in the major seed-potato-producing state of Santa Catarina where an outbreak of ToSRV was recently reported in tomato crops (1). Although ToSRV has been identified in other solanaceous crops in Brazil, especially tomato (Lycopersicon esculentum) and sweet pepper (Capsicum annum) (2), to our knowledge, this is the first report of ToSRV in potato in Brazil. Reference: (1) A. T. M. Lima et al. Fitopatol. Bras. 31:224, 2006. (2) D. N. Nozaki et al. Summa Phytopathol. 33:93, 2007. (3) M. R. Rojas et al. Plant Dis. 77:340, 1993. (4) J. A. C. Souza-Dias et al. CultivarHF 5(26):22, 2004.

A batata-semente (Solanum tuberosum) é considerada fator fundamental para garantir alta produtividade, qualidade de tubérculos e uma boa safra. O presente trabalho foi conduzido na Universidade José do Rosário Vellano (UNIFENAS), Alfenas-MG de setembro de 2007 a setembro de 2008 em três etapas distintas e sequenciais. Objetivou-se estudar o efeito da aplicação de reguladores de crescimento em brotos destacados de batata-semente na produção de minitubérculos; na brotação de minitubérculos e na produção comercial originada dos minitubérculos. Foram utilizados brotos de batata destacados de batata-semente (livre de vírus), da cultivar Bintje, originada de importação experimental do Alasca, com dois tamanhos: broto grande (média de 25 cm) e broto pequeno (média de 13 cm) e reguladores de crescimento AIB, GA3, BAP e 2,4D. O delineamento experimental para todos os trabalhos foi de blocos ao acaso em esquema fatorial 5 x 2 com três repetições. O número de minitubérculos produzido na primeira etapa originados de brotos grandes variou significativamente de 3,1 (GA3) a 7,7 (AIB) e de 2,3 (AIB) a 7,9 (controle) quando originados de brotos pequenos, enquanto que o peso variou de 7,5 g (GA3) a 10,6 g (AIB), empregando-se brotos grandes e de 2,7 (BAP) a 12,3 g (controle), com o uso de brotos pequenos. Os minitubérculos não apresentaram diferenças significativas para o tempo de brotação o que ocorreu num espaço de sete a oito dias. A produção comercial originada dos minitubérculos variou significativamente de 12,6 (GA3) a 29,5 t ha-1 (AIB), quando se avaliou brotos grandes e de 22,1 (BAP) a 30,4 t ha-1 (controle), com o uso de brotos pequenos. Conclui-se que os brotos de batata-semente, cultivar Bintje, podem ser usados para a produção de tubérculos-semente e não devem ser tratados com os reguladores de crescimento. Brotos menores destacados de batata-semente, cv. Bintje sem tratamento, devem ser preferidos para a produção de minitubérculos semente. The seed potatoes (Solanum tuberosum) are considered a key factor to ensure high productivity, quality of the tuber and a good harvest. This study was carried out at the University José Rosário Vellano (UNIFENAS), Alfenas, Minas Gerais state, Brazil, from September 2007 until September 2008 in three distinct and sequential stages. The objective was to study the effect of growth regulators applied on: (1) sprouts detached from seed-potato tubers on minituber yield, (2) sprouting minituber and (3) marketable yield originated from minitubers. Potato sprouts used were detached from seed potatoes tubers (virus free), cultivar Bintje, originated from an experimental import of sprouts from Alaska (USA), with two sizes: large sprouts (average of 25 cm) and small sprouts (average of 13 cm) and growth regulators IBA, GA3, BAP and 2,4D. The experimental design for all experiments was of randomized blocks in a factorial scheme 5x2 with three replications. The number of minitubers produced in the first stage originated from large sprouts varied significantly from 3.1 (GA3) to 7.7 (IBA) and 2.3 (IBA) to 7.9 (control), small prouts, while the weight varied from 7.5 g (GA3) to 10.6 g (IBA), large sprouts and 3.4 g (IBA) to 12.3 g (control), small sprouts. The minitubers did not show significant differences for the time of shooting which occurred within seven to eight days. Marketable production originated from minitubers varied significantly from 12.06 t ha-1 (GA3) to 29.51 t ha-1 (AIB), large sprouts and 22.11 t ha-1 (BAP) to 30.35 t ha-1 (control), small sprout. Sprouts from seed-potato tubers cv Bintje, can be used for seed tuber production and should not be treated with growth regulators. Small sprouts, detached from seed potatoes, cultivar Bintje, without treatment, should be preferred for the production of seed-potato minitubers.

A doença azul do algodoeiro está associada a um vírus ainda pouco conhecido em suas características morfológicas e moleculares, tanto quanto a sua patologia e epidemiologia. O tipo de transmissão circulativa pelo afídeo vetor Aphis gossypii Glover, associado a recentes relatos de estudos moleculares, sustentam ser o agente etiológico uma espécie membro da família Luteoviridae. No presente trabalho, estudos anatômicos comparativos em plantas sadias e infectadas foram realizados com a finalidade de conhecer aspectos estruturais da interação vírus-espécie hospedeira, com potencial aplicação na área de diagnose e melhoramento genético. Os estudos anatômicos foram realizados em folhas de plantas infectadas, com área foliar reduzida, nervuras cloróticas e margem foliar voltada para baixo. O encurtamento dos entrenós, que resultam em um agrupamento de folhas, flores e frutos, e conseqüente redução da altura da planta, do número e tamanho dos frutos, são expressões fenotípicas da planta de algodão infectada, a qual serviu para o presente estudo. Nas plantas infectadas com o agente da doença azul havia maior acúmulo de calose e de cristais de oxalato de cálcio, cloroplastos íntegros distribuídos na região periférica das células do mesofilo e aparente alteração química no interior das células do parênquima paliçádico. Inclusões nos vasos do floema e, ocasionalmente no xilema, também foram observadas. O acúmulo de calose e a presença de inclusões no floema podem indicar uma relação ou preferência do vírus por esse tecido.Cotton blue disease is caused by a virus whose morphological and molecular characteristics is not well known and so demanding information its phytosanitary and epidemiological characteristics. Evidences of an aphid borne (Aphis gossypii Glover) circulative (persistent) type of transmission, associated with a recent molecular report, sustain for a virus species belonging to the Luteoviridae family. Aiming to understand virus-host pathogenesis as well as to contribute with diagnostic and breeding aspects of cotton blue disease, in the present work, structural studies were performed via anatomical comparative analysis of health and infected plant tissues. For the anatomical studies, leaves from infected cotton plants were chosen when showing typical symptoms, such as: stunting, reduced leaf area with chlorotic vein and edges curled downward; clustered leaves, flowers and fruits due to reduced stem internodes. The results revealed that infected tissues present an increase in callose accumulation and calcium oxalate crystals; integrity of chloroplasts, which were distributed on the peripheral mesophyll cells, revealed a chemical alteration in the interior of palisade parenchyma cells. Inclusions in phloem and occasionally also xylem vessels were observed. The callose accumulation and the presence of inclusions in the phloem vessels are indications of a preferential relationship of the virus to these tissues.

Potato has significant importance for human feeding, and shows great yield potential. However, viruses transmitted by vectors have caused severe yield losses in this crop. It results in the dependency of import batches of virus free potato-seeds. The aim of this study was to analyse the influence of the fungicide Metiram+ Pyraclostrobin on the translocation of PVY virus into the plant with primary infection, and on yield. Also, the purpose was to evaluate the transmission capacity of this virus using different amounts of aphids. The experiments were carried out in a greenhouse located at the Campinas Agronomic Institute (InstitutoAgronomico de Campinas-IAC) in 2007.Healthy potato plants of cultivars Agata and Markies were used in order to study the fungicide effect, and potato plants of cultivar Bintje was used as the PVY source. For virus dissemination analysis, it was used healthy potato plants of cultivar Agata, and infected potato plants of cultivar Monalisa. According to the results, fungicide Metiram + Pyraclostrobin did not control the PVY virus translocation, and did not have positive effect on yield, although it delayed the plants senescence. It was also observed transmission of viruses with the lowest number of aphids used, highlighting the ease of dissemination of PVY by aphids. Due to the e asy transmission of PVY virus by aphids, and damage caused on potato, more studies are needed to understand the dissemination of viral diseases and improve the management techniques used by farmers against this problem in this crop.

Novo sistema de producao de batata-semente livre de virus e outros patogenos. Tecnologia inovadora para o mercado de “semente basica” e pioneira na exploracao do potencial brasileiro ao mercado de exportacao de “batata-semente” com maior seguranca sanitaria e menor custo de transporte comparado ao sistema convencional do tuberculo/batata-semente.

A doença azul do algodoeiro está associada a um vírus ainda pouco conhecido em suas características morfológicas e moleculares, tanto quanto a sua patologia e epidemiologia. O tipo de transmissão circulativa pelo afídeo vetor Aphis gossypii Glover, associado a recentes relatos de estudos moleculares, sustentam ser o agente etiológico uma espécie membro da família Luteoviridae. No presente trabalho, estudos anatômicos comparativos em plantas sadias e infectadas foram realizados com a finalidade de conhecer aspectos estruturais da interação vírus-espécie hospedeira, com potencial aplicação na área de diagnose e melhoramento genético. Os estudos anatômicos foram realizados em folhas de plantas infectadas, com área foliar reduzida, nervuras cloróticas e margem foliar voltada para baixo. O encurtamento dos entrenós, que resultam em um agrupamento de folhas, flores e frutos, e conseqüente redução da altura da planta, do número e tamanho dos frutos, são expressões fenotípicas da planta de algodão infectada, a qual serviu para o presente estudo. Nas plantas infectadas com o agente da doença azul havia maior acúmulo de calose e de cristais de oxalato de cálcio, cloroplastos íntegros distribuídos na região periférica das células do mesofilo e aparente alteração química no interior das células do parênquima paliçádico. Inclusões nos vasos do floema e, ocasionalmente no xilema, também foram observadas. O acúmulo de calose e a presença de inclusões no floema podem indicar uma relação ou preferência do vírus por esse tecido. Cotton blue disease is caused by a virus whose morphological and molecular characteristics is not well known and so demanding information its phytosanitary and epidemiological characteristics. Evidences of an aphid borne (Aphis gossypii Glover) circulative (persistent) type of transmission, associated with a recent molecular report, sustain for a virus species belonging to the Luteoviridae family. Aiming to understand virus-host pathogenesis as well as to contribute with diagnostic and breeding aspects of cotton blue disease, in the present work, structural studies were performed via anatomical comparative analysis of health and infected plant tissues. For the anatomical studies, leaves from infected cotton plants were chosen when showing typical symptoms, such as: stunting, reduced leaf area with chlorotic vein and edges curled downward; clustered leaves, flowers and fruits due to reduced stem internodes. The results revealed that infected tissues present an increase in callose accumulation and calcium oxalate crystals; integrity of chloroplasts, which were distributed on the peripheral mesophyll cells, revealed a chemical alteration in the interior of palisade parenchyma cells. Inclusions in phloem and occasionally also xylem vessels were observed. The callose accumulation and the presence of inclusions in the phloem vessels are indications of a preferential relationship of the virus to these tissues.

Plantas de tomateiro (Lycopersicon esculentum) apresentando sintomas de amarelecimento do limbo foliar principalmente nas nervuras, redução de crescimento e distorções foliares foram coletadas em lavouras do cinturão verde de Campinas, São Paulo, e mantidas no Centro Experimental de Campinas (IAC), para utilização em experimentos de avaliação de resistência de genótipos à virose. A partir de análises moleculares, o vírus foi identificado como Tomato yellow vein streak virus (TYVSV). Foram feitas avaliações em campo (infecção natural) e em telado (infecção natural e controlada), usando-se diversos genótipos, abrangendo cultivares, híbridos, linhagens e populações, além de espécies selvagens de tomateiro. Alguns dos genótipos e híbridos contêm o gene de resistência Ty-1. Em campo, destacou-se o híbrido 'BX 1016158' com as menores incidências de doença. Em telado (infecção natural), híbridos interespecíficos de L. esculentum x L. peruvianum, e a linhagem PI 134417 (L. hirsutum) mostraram-se os mais resistentes ao isolado. O método de avaliação precoce em telado (infecção controlada) mostrou-se adequado para discriminar genótipos resistentes ao isolado. Por meio desse método, constatou-se a resistência das linhagens 'LA 444-1' (L. peruvianum), F4(TySw5) e a série IAC 14-2, e dos híbridos 'Franco' e BX1653088 ('Densus'), os quais receberam notas próximas de um ou não apresentaram sintomas. Tomato (Lycopersicon esculentum) plant showing symptoms attributed to geminivirus were collected from crops of the green belt of Campinas, SP. The symptoms consisted of leaf yellowing, especially along the veins, leaf distortion and reduced plant growth. A virus isolate was maintained in tomatoplants by whiteflies transmission at the Experimental Center of Instituto Agronômico in Campinas. Molecular tests were performed with the virus, which showed to be Tomato yellow vein streak virus (TYVSV). Evaluations of tomato resistance were done under field (natural infections) and screen house conditions (natural and controlled infections) using genotypes of diverse origins, comprising cultivars, hybrids, breeding lines, populations and wild tomato species. The evaluated material included experimental genotypes and hybrids carrying the gene for vertical resistance, Ty-1. In the field, the evaluations pointed to the hybrid 'BX 1016158' as having the the lowest disease infection rates. In screen house conditions, the interspecific hybrids of L. esculentum x L. peruvianum, and the access PI 134417 of L. hirsutum showed the highest resistance to the virus. Another screen house experiment used a method of early testing for resistance of tomato genotypes to geminivirus. This method proved to be adequate for discrimination of genotypes, found resistance in the L. peruvianum access LA 444-1, in the IAC 14-2 series, in the F4 line TySw5, and in the hybrids 'Franco' and BX 1653088 ('Densus'), with ratings close to absence of symptoms.

Potato plants (Solanum tuberosum cv. Ágata) exhibiting symptoms of leaf roll and interveinal chlorosis, especially on older leaves, were found in a commercial crop in the County of Cristalina, State of Goiás, Brazil in June 2011. The crop was severely infested by whitefly Bemisia tabaci biotype B. Four potato tubers from symptomatic plants were indexed for the presence of the following viruses: Tomato chlorosis virus (ToCV), Potato leaf roll virus (PLRV), Tomato severe rugose virus (ToSRV), and Potato virus Y (PVY). Total RNA was extracted separately from each tuber and used for reverse transcription (RT)-PCR using the HS-11/HS-12 primer pair, which amplifies a fragment of 587 bp from the highly conserved region of the heat shock protein (HSP-70) homolog gene reported for ToCV. The RT-PCR product was subsequently tested by nested-PCR for detection of ToCV with specific primers ToC-5/ToC-6 (2). Amplicons of 463 bp, amplified from total RNA separately extracted from three tubers, were purified and directly sequenced. Comparisons among the three consensus sequences of 448 bp (GenBank Accession Nos. JQ288896, JQ288897, and JQ288898) revealed respectively, 98, 100, and 100% identity with the reported sequence of a tomato isolate of ToCV from Brazil (GenBank Accession No. EU868927) (1). For ToSRV detection, total DNA was extracted from two tubers and a fragment of approximately 820 bp was amplified by PCR with specific primers (3). PLRV and PVY were indexed in two and three tubers, respectively, by double-antibody sandwich-ELISA (SASA, Edinburg, Scotland). Virus-free B. tabaci biotype B were separately transferred to potato and tomato leaves infected with ToCV for an acquisition access period of 24 h. Groups of 30 viruliferous whitefly were transferred to four, young, sprout-grown potato plants cv. Ágata (two plants per virus isolate) for 24-h inoculation access period. After 37 days of inoculation, one plant inoculated with the potato and tomato isolates of ToCV, respectively exhibited symptoms of leaf roll and interveinal chlorosis on order leaves, which were similar to that induced by PLRV. Experimental infection of potato plants with ToCV, which induced leaf roll symptoms resembling PLRV infection, was reported in the United States by Wisler et al. (4). The potato isolate of ToCV was also transmitted by B. tabaci to one of two inoculated tomato plants. The presence of ToCV in all inoculated plants was detected by nested-RT-PCR as described above. To our knowledge, this is the first report on detection of ToCV in field potato plants in the world. Considering that ToCV occurs in innumerous countries around the world, it is transmitted by a cosmopolitan insect, and it induces symptoms similar to PLRV, this finding triggers an alert to field dependent seed-potato multiplication, virus inspector, and certification system. References: (1) J. C. Barbosa et al. Plant Dis. 92:1709, 2008. (2) C. I. Dovas et al. Plant Dis. 86:1345, 2002. (3) F. R. Fernandes et al. Trop. Plant Pathol. 35:43, 2010. (4) G. C. Wisler et al. Plant Dis. 82:270, 1998.

A implantação do teste da pré-cultura é condição necessária para a melhoria da certificação da batata-semente no Brasil. Esse teste permite o aprimoramento da determinação da sanidade do material produzido, principalmente no tocante à porcentagem de plantas contaminadas pelo vírus do enrolamento da folha da batata (VEFB), um dos principais fatores limitantes da produção de batata-semente, e de outros problemas fitossanitários transmissíveis pelo tubérculo. Um dos principais pontos de restrição a seu emprego é o tempo necessário para a obtenção de leitura final efetiva. Para determinar o melhor método de forçamento de gemas que permitisse a leitura final, foi realizado em 1983, no município de Tietê (SP), um ensaio com diferentes métodos de forçamento, empregando o cultivar Aracy (IAC-2), proveniente de campo com cerca de 20% de infecção do tubérculo-mãe pelo VEFB. Os tratamentos utilizados foram os seguintes: (1) testemunha; (2) tratamento de tubérculos com CS2, 30cm³/m³ de câmara, durante 48h; (3) imersão de gemas em solução contendo 1 ppm de ácido giberélico por 10 minutos; (4) idem, solução contendo 2ppm; (5) tratamento 2 + tratamento 3; (6) tratamento 2 + tratamento 4. Foram realizadas cinco observações, até 50 dias após o plantio, dos seguintes pontos: porcentagem de emergência, altura das plantas, número de folhas na haste principal e de hastes por gema, porcentagem de VEFB e facilidade de leitura. O plantio foi realizado em canteiros, com terra esterilizada, plantando gemas em espaçamento de 0,25 x 0,10 cm. Os tratamentos que propiciaram germinação precoce foram os que utilizaram a combinação dos dois produtos (CS2 e ácido giberélico), sendo a diferença diminuída no decorrer das leituras. O tratamento 5 apresentou plantas em condições ideais de leitura num período de tempo mais curto.For the Brazilian conditions, the determination of the quality of a potato field, grown for seed purposes cannot be done based only in field inspections. A post control method is already recommended, based on the removal of spheric seed pieces from the crown end of tuber samples and their planting for further determination of their phytosanitary quality. In order to determine the best way for breaking the dormancy of seed pieces of the cv. Aracy (IAC-2) a late cultivar, which ought produce plants of easy determination of secondary infection with the potato leafroll virus (PLRV), a trial was carried out with six treatments in 1983, at Tietê, State of São Paulo, Brazil. The treatments were: 1 - check control; 2 - whole tubers treated with CS2 (30 cc/m³ of chamber during 48 hours) and posterior removal of the eyes; 3 - immersion of the seed pieces in a solution containing 1 ppm of gibberellic acid (G.A.); 4 - the same, in a 2 ppm G.A solution; 5 - treatment 2 plus treatment 3; and 6 - treatment 2 plus treatment 4. The treatment 5 gave the best results. It is discussed the influente of the seed piece treatment in the percentage of a perfect stand, in four consecutive observations, spaced of two weeks; in the height of the plants; in the numbers of leaves in the major stem; in the number of stems per seed piece and in the development of PLRV symptoms.

A implantação do teste da pré-cultura é condição necessária para a melhoria da certificação da batata-semente no Brasil. Esse teste permite o aprimoramento da determinação da sanidade do material produzido, principalmente no tocante à porcentagem de plantas contaminadas pelo vírus do enrolamento da folha da batata (VEFB), um dos principais fatores limitantes da produção de batata-semente, e de outros problemas fitossanitários transmissíveis pelo tubérculo. Um dos principais pontos de restrição a seu emprego é o tempo necessário para a obtenção de leitura final efetiva. Para determinar o melhor método de forçamento de gemas que permitisse a leitura final, foi realizado em 1983, no município de Tietê (SP), um ensaio com diferentes métodos de forçamento, empregando o cultivar Aracy (IAC-2), proveniente de campo com cerca de 20% de infecção do tubérculo-mãe pelo VEFB. Os tratamentos utilizados foram os seguintes: (1) testemunha; (2) tratamento de tubérculos com CS2, 30cm³/m³ de câmara, durante 48h; (3) imersão de gemas em solução contendo 1 ppm de ácido giberélico por 10 minutos; (4) idem, solução contendo 2ppm; (5) tratamento 2 + tratamento 3; (6) tratamento 2 + tratamento 4. Foram realizadas cinco observações, até 50 dias após o plantio, dos seguintes pontos: porcentagem de emergência, altura das plantas, número de folhas na haste principal e de hastes por gema, porcentagem de VEFB e facilidade de leitura. O plantio foi realizado em canteiros, com terra esterilizada, plantando gemas em espaçamento de 0,25 x 0,10 cm. Os tratamentos que propiciaram germinação precoce foram os que utilizaram a combinação dos dois produtos (CS2 e ácido giberélico), sendo a diferença diminuída no decorrer das leituras. O tratamento 5 apresentou plantas em condições ideais de leitura num período de tempo mais curto. For the Brazilian conditions, the determination of the quality of a potato field, grown for seed purposes cannot be done based only in field inspections. A post control method is already recommended, based on the removal of spheric seed pieces from the crown end of tuber samples and their planting for further determination of their phytosanitary quality. In order to determine the best way for breaking the dormancy of seed pieces of the cv. Aracy (IAC-2) a late cultivar, which ought produce plants of easy determination of secondary infection with the potato leafroll virus (PLRV), a trial was carried out with six treatments in 1983, at Tietê, State of São Paulo, Brazil. The treatments were: 1 - check control; 2 - whole tubers treated with CS2 (30 cc/m³ of chamber during 48 hours) and posterior removal of the eyes; 3 - immersion of the seed pieces in a solution containing 1 ppm of gibberellic acid (G.A.); 4 - the same, in a 2 ppm G.A solution; 5 - treatment 2 plus treatment 3; and 6 - treatment 2 plus treatment 4. The treatment 5 gave the best results. It is discussed the influente of the seed piece treatment in the percentage of a perfect stand, in four consecutive observations, spaced of two weeks; in the height of the plants; in the numbers of leaves in the major stem; in the number of stems per seed piece and in the development of PLRV symptoms.

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T19:01:11Z No. of bitstreams: 1 S0103-90162009000200017.pdf: 207393 bytes, checksum: 5fa78ebfc2105b3afe473be901b0c627 (MD5) Made available in DSpace on 2013-08-22T19:01:11Z (GMT). No. of bitstreams: 1 S0103-90162009000200017.pdf: 207393 bytes, checksum: 5fa78ebfc2105b3afe473be901b0c627 (MD5) Previous issue date: 2009-04-01 Made available in DSpace on 2013-09-30T20:00:56Z (GMT). No. of bitstreams: 2 S0103-90162009000200017.pdf: 207393 bytes, checksum: 5fa78ebfc2105b3afe473be901b0c627 (MD5) S0103-90162009000200017.pdf.txt: 13214 bytes, checksum: d220d6df1048a0e93dd872aa8ecf3d86 (MD5) Previous issue date: 2009-04-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T15:15:36Z No. of bitstreams: 2 S0103-90162009000200017.pdf: 207393 bytes, checksum: 5fa78ebfc2105b3afe473be901b0c627 (MD5) S0103-90162009000200017.pdf.txt: 13214 bytes, checksum: d220d6df1048a0e93dd872aa8ecf3d86 (MD5) Made available in DSpace on 2014-05-20T15:15:36Z (GMT). No. of bitstreams: 2 S0103-90162009000200017.pdf: 207393 bytes, checksum: 5fa78ebfc2105b3afe473be901b0c627 (MD5) S0103-90162009000200017.pdf.txt: 13214 bytes, checksum: d220d6df1048a0e93dd872aa8ecf3d86 (MD5) Previous issue date: 2009-04-01 Plantas de Capsicum annuum cv. Magali R, resistentes ao Pepper yellow mosaic virus (PepYMV), exibindo sintomas severos de mosaico amarelo, malformação foliar e subdesenvolvimento foram encontradas em plantios na região de Lins, SP, Brasil, em 2003/04. Partículas semelhantes àquelas do gênero Potyvirus foram observadas em extrato foliar de planta infectada examinado em microscópio eletrônico de transmissão. O extrato foliar também reagiu com anti-soro contra o PepYMV em PTA-ELISA. Além de C. annuum cv. Magali R, esse potyvirus também infectou sistemicamente C. annuum cv. Rubia R, que é resistente ao PepYMV. A seqüência de nucleotídeos de parte do gene da proteína capsidial (CP) desse potyvirus apresentou 96-98% de identidade com a de outros isolados do PepYMV. A seqüência parcial de nucleotídeos da região 3' não traduzida (3' NTR) apresentou 94-96% de identidade com a do PepYMV. Esses resultados são indicativos de que o potyvirus que quebrou a resistência em pimentão é um isolado do PepYMV. Plants of Capsicum annuum cv. Magali R, resistant to Pepper yellow mosaic virus (PepYMV), which showed severe yellow mosaic, leaf malformation and stunting were observed during the 2003/04 growing season in Lins, São Paulo State, Brazil. Potyvirus-like particles observed in leaf sap from infected plants under the electron microscope reacted with an antiserum against PepYMV in PTA-ELISA. In addition to C. annuum cv. Magali R, this potyvirus also infected systemically the resistant C. annuum cv. Rubia R. The nucleotide sequence of part of the CP gene of this potyvirus shared 96-98% identity with that of other PepYMV isolates. The partial nucleotide sequence of the 3' NTR showed 94-96% identity with that of PepYMV. These data indicate that this potyvirus is a resistance-breaking isolate of PepYMV. Sakata Seed Sudamerica Ltda UNESP FCA Depto. de Produção Vegetal USP ESALQ Depto. de Entomologia, Fitopatologia e Zoologia Agrícola APTA IAC UNESP FCA Depto. de Produção Vegetal