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The projected impact of global warming on coffee production may require the heatadapted genotypes in the next decades. To identify cellular strategies in response to warmer temperatures, we compared the effect of elevated temperature on two commercial Coffea arabica L. genotypes exploring leaf physiology, transcriptome, and carbohydrate/protein composition. Growth temperatures were 23/19°C (day/night), as optimal condition (OpT), and 30/26°C (day/night) as a possible warmer scenario (WaT). The cv. Acauã showed lower levels of leaf temperature (Tleaf) under both conditions compared to cv. Catuaı, whereas slightly or no differences for other leaf physiological parameters. Therefore, to explore temperature responsive pathways the leaf transcriptome was examined using RNAseq. Genotypes showed a marked number of differentially-expressed genes (DEGs) under OpT, however DEGs strongly decrease in both at WaT condition indicating a transcriptional constraint. DEGs responsive to WaT revealed shared and genotype-specific genes mostly related to carbohydrate metabolism. Under OpT, leaf starch content was greater in cv. Acauã and, as WaT temperature was imposed, the leaf soluble sugar did not change in contrast to cv. Catuaı, although the levels of leaf starch, sucrose, and leaf protein decreased in both genotypes. These findings revealed intraspecific differences in the underlying transcriptional and metabolic interconnected pathways responsive to warmer temperatures, which is potentially linked to thermotolerance, and thus may be useful as biomarkers in breeding for a changing climate.

Potassium fertilizer and irrigation management in the progress of fungal diseases and yield of watermelonAmong the major diseases of watermelon, gummy stem blight (Didymella bryoniae) and downy mildew (Pseudoperonospora cubensis) stand out because they cause great losses in productivity and fruit quality. To investigate the influence of potassium fertilization on the progress of gummy stem blight and yield of watermelon and the influence of the water depth and the interval of irrigation in the progress of mildew, two assays were carried out under field conditions in Gurupi, Tocantins state, Brazil, in 2009 and 2010. The assay I was carried out in blocks and the treatments consisted of three doses of potassium applied (0, 50 and 100 kg/ha using KCl) and 12 replications. We evaluated the severity of gummy stem blight through a scale and the production data and fruit quality. In the assay II, we used a randomized complete block design with four replications in a factorial 3 x 3, three irrigation levels (100, 300 and 500 mm of water during the crop cycle) and three irrigation intervals. We evaluated the severity of downy mildew addition, the production and fruit quality. Doses of potassium did not affect the progress of gummy stem blight and the number, weight and fruit quality. The irrigation applied influenced the progress of downy mildew. Higher levels of severity of downy mildew were observed in plants cultivated under irrigation with levels of 500 mm of water. The amount of water applied also significantly influenced the production and fruit quality. We observed the presence of more crooked or deformed fruits in plants kept under water using a level of 100 mm. The highest total and marketable yield were obtained in plants irrigated with the level of 500 mm of water.

O uso de microrganismos é uma alternativa para o controle de doenças em plantas. Todavia, é prudente verificar a interação desse com os demais métodos de controle empregados em determinada cultura. Dessa forma, objetivou-se avaliar a fungitoxicidade dos herbicidas sobre o crescimento e desenvolvimento dos isolados de Trichoderma spp. Utilizou-se o delineamento inteiramente casualizado, em esquema fatorial 6 x 6 x 4, com quatro repetições. O fator A correspondeu aos herbicidas pendimethalin, clomazone, carfentrazone-ethyl, oxadiazon, thiobencarb + propanil e byspiribac-sodium; o fator B, às doses dos herbicidas - 0, 25, 50, 75, 100 e 200% da dose recomendada; e o fator C, aos isolados de Trichoderma spp. AJAM 18, CE 66, TRI 01 e TRI 02. O ensaio foi realizado em condições in vitro; avaliaram-se o crescimento micelial radial (CMR) e a esporulação dos isolados após aplicação dos herbicidas. Observaram-se diferenças de sensibilidade dos isolados para o mesmo produto testado. O oxadiazon reduziu o CMR dos isolados AJAM 18 e TRI 01 em 66 e 35%, respectivamente. No entanto, reduziu apenas 16% do CMR do isolado TRI 02 e não alterou o CMR do isolado CE 66 mesmo em 200% da dose recomendada. Verificaram-se diferentes efeitos dos produtos em cada isolado. A mistura comercial de thiobencarb+propanil foi altamente tóxica aos isolados de Trichoderma spp., com reduções em torno de 85% no CMR e no número de esporos. Por outro lado, o byspiribac-sodium pouco afetou os isolados, apresentando reduções inferiores a 10% no CMR e na esporulação. O carfentrazone-ethyl e byspiribac-sodium demonstraram ser compatíveis com os isolados de Trichoderma spp. estudados.

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Severity of foliar diseases and genotype maize yield in response to nitrogen fertilizationLeaf diseases, mainly, helmintosporiosis (Bipolaris spp.), anthracnose (Colletotrichum graminicola) and rust (Puccinia spp.), may cause reduction in maize yield. This study aimed to evaluate the occurrence and severity of helmintosporiosis, anthracnose and rust, as well as productivity of different genotypes of maize in response to increasing doses of nitrogen. Disease severity was evaluated using a score scale in nine maize genotypes (AG9040, AG7088, 30F35, 3F624, 1F583, 1F632, 1F557, 1F640 and ID219) subjected to four different nitrogen levels (67; 112; 157; and 202 kg ha -1 ) in two cropping years (2009/2010 and 2010/2011). To determine the productivity, it was used the weight of collected grains. It was observe that the severity of helmintosporiosis, anthracnose and rust varied in response to nitrogen levels and between the genotypes evaluated during two cropping years, although there was no clear relationship As doenças foliares, principalmente, helmintosporiose (Bipolaris spp.), antracnose (Colletotrichum graminicola) e ferrugem (Puccinia spp.), podem ocasionar redução do rendimento da cultura do milho. Este estudo teve como objetivo avaliar a ocorrência e severidade de helmintosporiose, antracnose e ferrugem, bem como a produtividade de genótipos de milho, em resposta a doses crescentes de nitrogênio. Avaliou-se a severidade das doenças, utilizando-se escala de notas, em nove genótipos de milho (AG9040, AG7088, 30F35, 3F624, 1F583, 1F632, 1F557, 1F640 e ID219), submetidos a quatro doses de nitrogênio (67; 112; 157; e 202 kg ha -1 ), em duas safras (2009/2010 e 2010/2011). Para determinar a produtividade, utilizou-se a massa dos grãos coletados. Os graus de severidade da helmintosporiose, da antracnose e da ferrugem variaram em resposta às doses de nitrogênio e, entre os genótipos de milho avaliados durante as duas safras, entretanto, não houve relação clara entre as doses de nitrogênio aplicadas e a ocorrência das doenças nas duas safras. A ferrugem foi detectada apenas durante a safra I. Apesar da severidade das doenças foliares, elas, de modo geral, não afetaram significativamente a produtividade dos genótipos de milho avaliados. Desses, o genótipo de milho AG7088 pode ser considerado o mais produtivo e o mais resistente às doenças avaliadas.Palavras-chave: helmintosporiose, antracnose, ferrugem, Zea mays, nitrogênio.

Reaction of experimental watermelon genotypes to gummy stem blightThe gummy stem blight, caused by the fungus Didymella bryoniae is one of the major diseases that occur in watermelon, causing seedling damping off and canker formation on the stems and stalks, reducing the yield and quality of fruits. Although sources of genetic resistance to this disease are available, in Brazil there are very few studies on this subject and the results so far obtained are not satisfactory for adoption in the field. The objective of this research was to select D. bryoniae isolates and evaluate the reaction of experimental genotypes of watermelon to gummy stem blight under greenhouse and field conditions. Under greenhouse conditions a variation was observed, regarding resistance level among genotypes. Some genotypes that were resistant in the greenhouse also behaved as resistant in the field. The genotypes

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