Phenotypical correlations between agronomical characters in type pome bananas and its implications on yield estimate.

Estimates of phenotypic correlations involving banana production, yield components and other important characters can be found in several articles (1). However, for the same character, it can be identified a positive, negative or null value estimate. This can be explained by the fact that these correlations have been estimated in different genotypes and environments with the use of different methods. In view of this, if possible, new correlations must be estimated to assist the conduction a breeding program

Glyphosate translocation in herbicide tolerant plants

The objective of this study was to evaluate glyphosate translocation in glyphosate-tolerant weed species (I. nil, T. procumbens and S. latifolia) compared to glyphosate-susceptible species (B. pilosa). The evaluations of 14C-glyphosate absorption and translocation were performed at 6, 12, 36 and 72 hours after treatment (HAT) in I. nil and B. pilosa, and only at 72 HAT in the species T. procumbens and S. latifolia. The plants were collected and fractionated into application leaf, other leaves, stems, and roots. In S. latifolia, approximately 88% of the glyphosate remained in the application leaf and a small amount was translocated to roots at 72 HAT. However, 75% of the herbicide applied on T. procumbens remained in the leaf that had received the treatment, with greater glyphosate translocation to the floral bud. It was concluded that the smaller amount of glyphosate observed in S. latifolia and T. procumbens may partly account for their higher tolerance to glyphosate. However, I. nil tolerance to glyphosate may be associated with other factors such as metabolization, root exudation or compartmentalization, because a large amount of the herbicide reached the roots of this species.Objetivou-se neste estudo avaliar a translocação de glyphosate em plantas tolerantes (Ipomoea nil, Tridax procumbens e Spermacoce latifolia) e suscetível (Bidens pilosa) a esse herbicida. As avaliações de absorção e translocação do 14C-glyphosate em I. nil e B. pilosa foram efetuadas às 6, 12, 36 e 72 horas após a aplicação do herbicida (HAT), e em T. procumbens e S. latifolia, às 72 HAT. As plantas foram coletadas e fracionadas em: folha de aplicação, demais folhas, caules e raízes; em T. procumbens e S. latifolia, avaliou-se a presença do produto na inflorescência da planta. Em S. latifolia, aproximadamente 88% do glyphosate permaneceu na folha de aplicação, e pequena quantidade translocou para as raízes. Todavia, em T. procumbens, 75% do herbicida permaneceu na folha que recebeu a aplicação, observando-se maior translocação na inflorescência em relação às raízes. Conclui-se que a menor translocação do glyphosate observada em S. latifolia e T. procumbens pode ser um dos fatores responsáveis pela maior tolerância dessas espécies ao herbicida, ao passo que em I. nil a metabolização, a exsudação radicular ou a compartimentalização podem favorecer a tolerância, já que grande quantidade do produto atingiu as raízes da espécie

Glyphosate translocation in herbicide tolerant plants.

The objective of this study was to evaluate glyphosate translocation in glyphosate-tolerant weed species (I.nil, T.procumbens and S.latifolia) compared to glyphosate-susceptible species (B. pilosa). The evaluations of 14 C-glyphosate absorption and translocation were performed at 6, 12, 36 and 72 hours after treatment (HAT) in I. nil and B. pilosa, and only at 72 HAT in the species T. procumbens and S. latifolia. The plants were collected and fractionated into application leaf, other leaves, stems, and roots. In S. latifolia, approximately 88% of the glyphosate remained in the application leaf and a small amount was translocated to roots at 72 HAT. However, 75% of the herbicide applied on T. procumbens remained in the leaf that had received the treatment, with greater glyphosate translocation to the floral bud. It was concluded that the smaller amount of glyphosate observed in S. latifolia and T. procumbens may partly account for their higher tolerance to glyphosate. However, I.nil tolerance to glyphosate may be associated with other factors such as metabolization, root exudation or compartmentalization, because a large amount of the herbicide reached the roots of this species

Brazilian banana crop: current situation and research challenges.

Brazil is the worlds fifth largest producer of bananas, with 7.3 million Mg, 503 thousand ha and average yield of 14.6 Mg ha-1. The country also holds an important market with unique characteristics. In the Northern and Northeastern regions, AAB varieties such as Pacovan, Dwarf Prata and Terra dominate. In the Southeastern region, AAB Prata, Dwarf Prata and Maçã and AAA Cavendish type, in that order. In the Southern region, Cavendish varieties and the Prata type, and, in the Midwest, Prata type and Maçã. In the main banana producing centers of the country, in general, the climatic conditions are suitable, except for water limitation in the North of Minas Gerais, Medium and Submedium São Francisco in Bahia, Submedium São Francisco at Pernambuco, Jaguaribe-Apodi in Ceará and Mossoró/Açú in Rio Grande do Norte, overcome with the use of irrigation; and low temperatures in São Paulo and in the South. Research with the crop began in 1925 in São Paulo, and became more consistent after the 1970s. The Brazilian system of agricultural research is constituted by the Brazilian Agricultural Research Company, state research companies, federal and state universities and other research, teaching and extension institutions. More than a fifth of the 453 articles published in leading scientific journals in Brazil, in the last 20 years, developed the theme improved genotypes. The Brazilian Banana Breeding Program, coordinated by Embrapa Cassava and Fruits, began in 1983 and made available to farmers several genotypes, since 1995. In the North of the country, where black Sigatoka is present and there are climatic conditions favorable to the pathogen, there was greater adoption the new genotypes. The banana crop in Brazil has evolved greatly in recent decades, due to the generation, adaptation and diffusion of technology, but also the organization of banana growers. Some highly technified production centers emerged, especially in irrigated areas, disseminating information and functioning as showcases positive for producers

Sugarcane cultivars present differential susceptibility to herbicides ametryn and trifloxysulfuron-sodium.

Weed management in Brazilian sugarcane fields is accomplished mainly with herbicides. These chemical products may negatively impact sugarcane growth and development. Therefore, we aimed this study to evaluate the influence of the selective herbicides ametryn, trifloxysulfurom-sodium and its commercially available mixture on the growth of sugarcane cultivars. The experiment was conducted under greenhouse condition in a completely randomized design, using a 3×3×4 factorial scheme with four replications. Factor A comprised sugarcane cultivars (SP80-1816, RB855113 and RB867515); factor B herbicides ametryn (Metrimex®), trifloxysulfuron-sodium (Envoke®) and its mixture (Krismat®), and factor C the doses (0.0, 0.5x, 1.0x and 3.0x the label dose), where 1.0x dose= 2,000gha-1 for ametryn; 22.5gha-1 for trifloxysulfuron-sodium and 1, 463+37.0gha-1 for the mixture. Crop toxicity was assessed 28 days after herbicide application and traits such as plant height, number of leaves per plant, stalk diameter, leaf area index, specific leaf area and crop growth rate were assessed 80 days after crop emergence. The results showed that trifloxysulfuron-sodium causes lower impact on all variables; therefore, being more selective to all cultivars. The label dose (1.0x), equivalent to 2,000 gha-1 of ametryn and 22.5 gha-1 of trifloxysulfuron- sodium is considered as a threshold between deficient weed control (in lower doses) and excessive crop toxicity (in higher doses). RB867515 and RB855113, respectively, were the most and least tolerant cultivars to both herbicides. In highly infested planting fields, farmers usually prefer to grow the most tolerant sugarcane cultivar when applying ametryn or trifloxysulfurom sodium

Características micromorfológicas de biótipos de capim-arroz resistente e suscetível ao quinclorac.

RESUMO - O objetivo deste trabalho foi avaliar o efeito do quinclorac nas características anatômicas de folhas e raízes de biótipos de capim‑arroz (Echinochloa spp.), resistente e suscetível a este herbicida, por meio de avaliações micromorfométricas. As plantas foram cultivadas em vasos de plástico com capacidade de 250 cm3. As imagens dos cortes foram obtidas com microscópio de luz equipado com sistema U‑Photo, acoplado à câmera digital conectada a microcomputador. Na seção transversal da lâmina foliar e das raízes, utilizouse objetiva de 10X, tendo-se avaliado 20 cortes/campos por planta, com dez medições por corte e quatro repetições por tratamento. Observaram-se diferenças entre os biótipos resistente e suscetível, tanto na ausência quanto na presença do quinclorac. O biótipo resistente apresenta lâmina foliar pouco afetada pelo herbicida; no entanto, há modificação na constituição dos tecidos radiculares com a formação mais acentuada de aerênquima. O biótipo suscetível também apresenta formação de aerênquima quando tratado com o quinclorac, mas em quantidade inferior à observada no biótipo resistente. ABSTRACT- The objective of this work was to evaluate the effect of quinclorac on anatomical traits of leaves and roots of barnyardgrass (Echinochloa spp.) biotypes, susceptible and resistant to this herbicide, by micromorphometric assessments. Plants were grown in plastic pots with 250 cm3 capacity. The images of plant sections were obtained with a light microscope equipped with a U‑Photo system, coupled to a digital photo camera connected to a microcomputer. For cross-sections of leaf blades and roots, 10X objectives were used, and 20 sections/fields per plant were evaluated, with ten measurements per section and four replicates per treatment. Differences were observed between resistant and susceptible biotypes, both in the absence and in the presence of quinclorac. The resistant biotype shows leaf blades that are less affected by the herbicide; however, there are changes in root tissue constitution with increased aerenchyma formation. The susceptible biotype also shows formation of aerenchyma when treated with quinclorac, but in lower levels than those observed for the resistant biotype

Produtividade de grãos de linhagens-elite de feijão branco no norte de Minas Gerais:ciclo de avaliação 2018-2019.

No Brasil são cultivados diferentes grupos comerciais de feijão-comum (Phaseolus vulgaris L.), existindo grande demanda de feijões ?especiais?, como o feijão branco, que atende um nicho de mercado específico com maior valor agregado e possibilidade de exportação. Assim, objetivou-se no presente trabalho avaliar a produtividade de linhagens-elite de feijão-comum do grupo ?branco? em diferentes épocas de cultivo no Norte de Minas Gerais.Evento online

Dynamics of the weed community during pineapple growth in the Brazilian semi-arid region.

The pineapple belongs to the family Bromeliaceae and is a slow-growing succulent monocot with a reduced superficial root system. For this reason, the interference of weeds in competition with this crop can cause significant losses to the production. One of the bases to elaborate a control strategy is the knowledge of the diversity of weeds that occur in the cultivated areas. The objective of this study was to identify the weed community during pineapple growth in a semi-arid climate region of Brazil. Weeds were collected 60, 120, 180, 240, 300, and 360 days after planting (DAP) the pineapple. These collections were made in three different plots every two months until floral induction, composed of three pineapple cultivars. The weed community found in the irrigated pineapple field, in semi-arid climate conditions, was mostly composed by species belonging to the families Amaranthaceae, Asteraceae, Convolvulaceae, Fabaceae, Malvaceae, and Poaceae. The highest diversity of weed species was found at 60 DAP. The species Ipomoea acuminata was present throughout the development of the pineapple and showed the highest importance value index in most of the periods evaluated during the pineapple growth.Título em espanhol: Dinámica de la comunidad de malezas a lo largo del crecimiento de piña en la región semiárida brasileña