No abstract

Agricultural crops are severely affected by salinity. Recent studies have shown that salt stress signaling components affect plant metabolism and stimulate the accumulation of organic osmolytes and antioxidant substances. This work aimed at assessing the growth and development of lemon balm, Melissa officinalis L., subjected to salt stress, as well as its antioxidant response, essential oil composition, and essential oil yield (%). A completely randomized experimental design was conducted under greenhouse conditions, where 30-days-old lemon balm plants were treated with different NaCl concentrations (0, 50, 100, 150 and 200 mM) for sixty days. The highest concentrations (150 mM and 200 mM NaCl) caused significant reductions in shoot height, shoot fresh mass, relative water content, water activity and chlorophyll production due to changes in osmotic activity. The activities of superoxide dismutase (SOD) and catalase (CAT) increased in plants subjected to salinity. In addition, membrane damage (DM) increased with increase in NaCl concentration. The yield of the essential oils decreased but the number of compounds increased in all the NaCl treatments. The compounds neryl-acetate and geranyl-acetate were detected at 100, 150 and 200mM NaCl, suggesting that under salt stress, lemon balm plants activate the metabolic pathways for the production of terpenoids, consequently producing monoterpenes. Salinity negatively affected most of the parameters evaluated in lemon balm plants. Our results show that lemon balm plants are tolerant to low concentrations of salinity (up to 50mM) as proved by their distinct metabolic responses.

This study aimed to assess the allelopathic potential of the aqueous extract of the shoot of Sorghum bicolor at different phenological stages on seed germination and initial growth of kale (Brassica oleracea var. acephala) seedlings, which is considered a bioindicator species. The experiment was carried out at five development stages of S. bicolor (40, 50, 60, 70, and 80 days after emergence), which was used as aqueous extract at six concentrations (0, 20, 40, 60, 80, and 100%) applied in four replications per treatment in 10 or 50 kale seeds per plot. The percentage of germination, germination rate index, root growth, shoot length, and dry matter of kale seedlings were analyzed in the presence of this extract on different days of collection and concentrations. The aqueous extract of S. bicolor presented an allelopathic effect on germination and initial growth of kale seeds, with a higher inhibitory effect when more concentrated extracts from pre-flowering plants were used, which corresponds to 60 days after emergence. Thus, this stage should be recommended in the use of S. bicolor straw to help in controlling weeds.

A estatística descritiva é o ramo da estatística que visa sumarizar e descrever qualquer conjunto de dados, em outras palavras, está preocupado em sintetizar os dados. A presente pesquisa tem como objeto a análise da variabilidade pluviométrica mensal e interanual no município de Canavieiras, localizado no litoral Sul do Estado da Bahia, a partir de série histórica (2005 a 2018) associado com as técnicas de estatística descritiva, com o auxílio do software gratuito BioEstat versão 5.3. Os dados pluviométricos foram extraídos do Portal Hidroweb integrante do Sistema Nacional de Informações sobre Recursos Hídricos (SNIRH), do qual a Agência Nacional de Águas (ANA) é responsável pela coordenação. A precipitação pluviométrica é um fator importante na definição do clima de um município. Seu estudo tem grande importância devido à influência que exerce sobre as condições ambientais e socioeconômicas. Por meio dos resultados, constatou-se grande variabilidade das precipitações no que tange ao desvio em relação à média, com a quadra chuvosa concentrada nos meses de março a julho e em novembro. Foi possível comprovar que o mês de abril destacou por ter a maior variabilidade, com maior desvio padrão e segundo maior coeficiente de variação.

No abstract

To make the coffee activity competitive, some farmers use precision coffee farming. Thus, it is possible to create thematic maps that guide management practices for regions where there are limitation for the plant development. The objective of this study was to identify the spatial dependence of coffee crop yield, in 2012 and 2013. The experimental area is located in a Haplustox in Três Pontas, Minas Gerais. One hundred sampling points were georeferenced for the collection of yield data through manual harvest. The difference of yield between crop seasons was also evaluated. Data were processed using geostatistical analysis. It was possible to identify and characterize the spatial dependence of all variables, as well as to create contour maps. There were differences between the 2012 and 2013 maps, due to the biennial coffee phenological cycle, which can be confirmed by the map of the difference between the crop seasons. It is recommended a crop management that considers the spatial variability of yield for greater economic return.

RESUMO-A podridão floral dos citros (PFC) é uma importante doença dessa cultura, responsável por elevadas perdas de produção. Normalmente, essa doença mostra-se limitante quando ocorrem prolongados períodos chuvosos durante o florescimento das plantas ou quando existe intenso molhamento foliar. Duas espécies de Colletotrichum estão associadas à doença: C. acutatum e C. gloeosporioides. Entretanto, recentemente, tem-se verificado que, mesmo sob condições não tão propícias, a doença tem ocorrido com relativa frequência, suspeitando-se do envolvimento de outras espécies de Colletotrichum ou de novas condições de adaptação das espécies descritas. Este trabalho teve como objetivo determinar se há ou não outra espécie de Colletotrichum associada a PFC e avaliar a viabilidade do emprego de marcadores moleculares ISSR na caracterização taxonômica de isolados de Colletotrichum spp. associados a sintomas de PFC em flores, assim como de tecidos foliares e frutos cítricos assintomáticos. Para tanto, foi empregada uma combinação de iniciadores específicos, levando em conta a região ITS e marcadores moleculares ISSR. Os marcadores ISSR mostraram-se eficientes na caracterização taxonômica dos isolados de Colletotrichum analisados. A população avaliada foi constituída apenas por C. acutatum e C. gloeosporioides, descartando o envolvimento de uma espécie adicional. Foi constatada alta diversidade genética entre os isolados analisados, o que também se mostra convergente quanto às diferenças fenotípicas observadas sob condições de campo. Entretanto, não foi encontrada relação quanto à origem e as espécies de Colletotrichum spp. associadas. De modo inédito, ainda que assintomaticamente, foi detectada a presença de um isolado de C. acutatum associado a frutos cítricos. Termos para indexação: Citrus sinensis, marcadores ISSR, região ITS. MOLECULAR ChARACTERIZATIOn OF Colletotrichum SPP. ISOLATES ASSOCIATED wITh POST-bLOOM FRUIT DROPAbSTRACT -Postbloom fruit drop of citrus (PFD) is a serious disease of this crop, accounting for high yield losses. Usually, this disease shows to be limiting when there are prolonged rainy periods during plant flowering or when there is intense leaf wetness. Two Colletotrichum species are associated with the disease: C. acutatum and C. gloeosporioides. However, recently, it has been found that, even under not so favorable conditions, the disease has occurred with some frequency; one suspects the involvement of other Colletotrichum species or new adaptation conditions of the described species. This study aimed to determine whether there is another Colletotrichum species associated with PFD and the viability of using molecular markers ISSR for taxonomic characterization of Colletotrichum spp. isolates associated with PFD symptoms in flowers, as well as of leaf tissues and asymptomatic citrus fruits. For this purpose, we used a combination of specific primers, taking into account the ITS region and ISSR molecular markers. ISSR markers have proven to be effective for taxonomic characterization of the Colletot...

Chia seed is expanding on the market due to its characteristics, but there are few studies on its response to residual fertilization of other crops. The objective was to evaluate the vegetative and productive parameters of common bean as a function of the base fertilization increment and to verify the influence of the residue of this fertilization on the development of chia. The experiment was carried out in two stages, Maringá State University, Umuarama Regional Campus, in a randomized block design with 4 replications. The treatments for the first stage were: T1 - doses recommended for beans and T2, T3, T4 and T5, were recommended doses for beans with increments for each treatment. The evaluated variables were: shoot dry matter, number of pods per plant, grains per plant, grains per pod, 1000 grains weight and yield. In the second stage, the experiment was installed in the same place of the previous cultivation. The treatments were: residual bean fertilization, T6 - plus the treatment with the recommendation for chia. The evaluated variables were: macro and micronutrient leaf contents, shoot dry matter, final plant population, 1.000 grains weight, oil content and yield. For beans and chia, soil samples were collected after harvest to evaluate chemical attributes. In common bean, the results were not significant in the evaluated parameters. In soil, the residual effect of beans was significant for P and K, with 27.2 mg dm −3 and 167.70 mg dm −3 , in treatment T5 and chia was 23.1 mg dm −3 and 89.7 mg dm −3 , for treatment T6, respectively. In chia, yield, oil content and P for leaf macro and micronutrient leaf contents were significant. Thus, the vegetative and productive parameters of the common bean were not influenced by the increase in fertilization. The residual effect was higher for P and K, for beans and chia. For chia, influences by residual effect were observed.