Selectivity of pre-emergence herbicides in potato cv. Innovator

<div><p>ABSTRACT Herbicide tolerance differs among potato cultivars. Thus, pre-emergence herbicides in potatoes need to be studied. We evaluated weed control, selectivity and potato yield of cv. Innovator with the herbicides clomazone, metribuzin and linuron. The experimental design was randomized blocks with four replications. One experiment was installed in 2014 (experiment 1, 5 treatments) and another in 2015 (experiment 2, 7 treatments), irrigated by central pivot in Perdizes-MG, Brazil. In experiment 1 treatments consisted of a control (T1), a hoed control (T2), clomazone (360 g ha-1) (T3), metribuzin (480 g ha-1) (T4), and linuron (990 g ha-1) (T5). The treatments in experiment 2 repeated those in experiment 1 (T1 to T5) and added clomazone + metribuzin (360 + 480 g ha-1)) (T6), and clomazone + linuron (360 + 990 g ha-1) (T7). We determined the number of stems per meter, length of longest stems, phytotoxicity, weed control, soluble solids content (%), yield and classification of tubers. The herbicides, either by themselves or in combination with another herbicide, provided 100% control of Eleusine indica and Digitaria horizontalis. Clomazone by itself or in combination with metribuzin or linuron provided the best control of Commelina benghalensis. Plots treated with clomazone presented phytotoxicity symptoms at 10 days after emergence (DAE); however, the plants recovered from these symptoms at 30 DAE. Metribuzin reduced soluble solids content, which affects industrial yield. The herbicides significantly influenced potato yield. In, 2014, the greatest “total” yields were observed in treatments with linuron (34.48 g ha-1) while the greatest “special” potato yields were achieved with clomazone (20.21 g ha-1) and linuron (21.13 g ha-1). In 2015, the greatest “total” yields were observed in treatments with clomazone [“special” (20.98 t ha-1) and “total” (35.11 t ha-1)] and metribuzin [“special” (20.85 t ha-1) and “total” (35.45 g ha-1)] followed by clomazone+linuron (30.95 g ha-1). Therefore, while metribuzin and linuron controlled Eleusine indica and Digitaria horizontalis, they may also reduce potato quality. Clomazone may be an option for controlling Eleusine indica, Digitaria horizontalis and Commelina benghalensis without affecting potato yield and soluble solids content.</p></div

Estaquia de rizomas do carapiá, planta medicinal em extinção Rhizome cuttings of Carapiá, a medicinal plant vulnerable to extinction

Dorstenia cayapia Vellozo, Moraceae (carapiá) é uma erva medicinal e nativa do Brasil. Pertence à categoria "vulnerável", devido à drástica redução dos seus habitats e ao declínio populacional. Esta pesquisa foi realizada em casa de vegetação pertencente ao Centro de Ciências Agrárias da Universidade Federal de Uberlândia. Teve como objetivo obter informações agronômicas que permitam cultivar e explorar racionalmente o carapiá, visando a obtenção de material cultivado para produtos fitoterápicos e indústria química. O material vegetal foi coletado em Raul Soares-MG, em um resquício de Floresta da Encosta Atlântica. Nesse experimento de estaquia de rizomas avaliaram-se três substratos: Substrato comercial, S1 (40% terra + 40% esterco bovino + 20% húmus) e S2 (20% terra + 20% esterco bovino + 40% húmus + 20% vermiculita); três partes de rizoma: apical, basal e mediano e dois tipos de bandeja de poliestireno expandido com 128 e 200 células. Adotaram-se estacas com o tamanho médio de 2 cm, que foram plantadas de acordo com o geotropismo positivo. Conduziu-se o experimento de abril a junho de 2007. O delineamento foi inteiramente casualisado em esquema fatorial (3x3x2). Determinou-se a brotação (%) aos 30 e 68 dias após o plantio (DAP) e as massas fresca e seca da parte aérea (folhas e inflorescências) e da parte subterrânea (rizomas e raiz) aos 68 DAP. Os substratos não tiveram efeito na brotação dos rizomas em bandejas aos 30 DAP. A brotação da parte apical do rizoma foi superior às brotações das posições basal e mediana do rizoma aos 68 DAP. Comparando o uso das bandejas de 128 e de 200 células, a brotação dos rizomas foi superior com o uso da bandeja de 128 células. Pode-se recomendar, para o plantio de Dorstenia cayapia, o corte da parte apical do rizoma, evitando-se assim, o arranquio da planta inteira, auxiliando na preservação dos indivíduos em seu ambiente natural e possibilitando sua propagação assexuada.<br>Dorstenia cayapia Vellozo, Moraceae (carapiá) is a Brazilian native medicinal herb that is classified as "vulnerable" because of the drastic reduction of its habitat and its declining population. This study was carried out in a greenhouse at the Center for Agricultural Sciences, Federal University of Uberlândia, Minas Gerais State, Brazil. The objective of the study was to obtain informations about cultivation and exploration of carapiá to obtain plant material for phytotherapy and chemical industry products. Plant material was collected in Raul Soares, Minas Gerais State, in a fragment of the Atlantic Coastal Forest. Three substrates were evaluated in the rhizome cutting experiment: Commercial substrate, S1 (40% soil + 40% cattle manure + 20% humus); S2 (20% soil + 20% cattle manure + 40% humus + 20% vermiculite); three sections of the rhizome: apical, basal and intermediate and two types of trays: 128 and 200 cells. Medium sized cuttings (2 cm) were prepared and planting was done according to positive geotropism. The experiment was carried out from April to June 2007 and the experimental design was completely randomized as a 3x3x2 factorial. Dry mass was determined for the above ground (leaves and inflorescences) and for the under ground (roots and rhizomes) parts of the plant. The rhizome tip sprouting was greater than those of the median and basal sections. Rhizome sprouting was better in the 128-cells tray than in the 200-cell tray. Collecting cuttings from the top of the rhizomes could be recommended for planting because it avoids removing the entire plant, thus preserving the plants in their environment and providing for the possibility of asexual propagation

Propagação vegetativa da alfavaca-cravo utilizando diferentes tipos de estacas e substratos Vegetative propagation of the wild basil using different types of cuttings and substrata

A propagação vegetativa é considerada importante ferramenta para o melhoramento de espécies lenhosas e herbáceas e vem sendo amplamente utilizada, visando melhorar e manter variedades de importância econômica e medicinal. Neste contexto utilizou-se estacas de alfavaca-cravo de 15 cm para apicais e 25 cm para as medianas, sendo estas com e sem folhas. As estacas foram plantadas em bandejas de isopor de 72 células, utilizando-se 10 substratos. Após 35 dias, as estacas foram retiradas com cuidado, sendo as partes aéreas e radiculares separadas e acondicionadas em saco de papel e mantidas em estufa a 70ºC por 48 h para posterior avaliação da matéria seca. Analisou-se a percentagem de enraizamento, número de folhas na estaca, peso de matéria seca de folha e de raiz. Não houve interação significativa entre os diferentes tipos de substrato e estaca para percentagem de enraizamento, sendo que os substratos de modo geral diferiram pouco entre si. Entre os tipos de estaca destacaram-se para esta variável a mediana sem folha e a apical com folha. Para as demais variáveis houve interação significativa entre o tipo de estaca e o substrato. A melhor estaca foi a mediana sem folhas plantadas em substrato arisco + esterco + húmus e vermiculita nas seguintes proporções: 20%:40%:40%; 40%:20%:40% e 40%:40%.<br>The vegetative propagation is an important tool for the improvement of woody and herbaceous species and could be an important tool to improve and to maintain varieties of economic and medicinal importance. In this experiment cuttings 15 cm long of the apical portion and also 25 cm long cuttings of the medial portion of the stems, were used both with and without leaves. The cuttings were planted on styrofoam trays with 72 cells, using 10 different substrata. After 35 days, cuttings were carefully removed, the aerial portion being separated from the roots and conditioned in paper bags and maintained in a stove at 70ºC for 48 h, for the dry weight evaluation. There were analyzed the percentage of rooting, number of leaves per cutting and leaf and root dry weight. There was no interaction among substrata and cuttings for the percentage of rooting. Were no significant differences in the rooting among the different substrata used in the experiment there. Better rooting was observed on cuttings from the medial portion of the stem without leaves and from the apical portion with leaves. For the other variables there was significant interaction between the cuttings and the substrata. The cutting that presented best results were those from the medial portion without leaves in the substrata with A+E sandy soil + humus + vermiculite in the following proportions: (20%: 40%:40%); (40%:20%:40%) and (40%:40%:20%) respectively