Geraldo Chavarria

Microclima de vinhedos sob cultivo protegido

Microclimate alterations promoted by plastic covering over vineyards interfere in the plant physiology and fungal diseases incidence on grapevines. The aim of this research was to evaluate the influence of the plastic covering on the microclimate of vineyards, in particular on the quality of the incoming solar radiation. The experiment was carried out in 2005/06 and 2006/07 seasons in Flores da Cunha-RS, in a vineyard of Moscato Giallo cultivar shaped in Y, with impermeable plastic (160μm) over 12 rows of 35m length and five rows without covering (control). In both treatments the air temperature and humidity, incoming photosynthetically radiation and wind speed were measured at the level of the canopy and clusters. Continuing measurements were taken through sensors and automatic acquisition systems (datalogger). Influences of the covering on quality of the incoming solar radiation, from 300 to 750nm, were evaluated through a spectroradiometer. The impermeable plastic covering above the plant rows increased the air temperature and decreased the photosynthetically radiation and wind speed. The covering interfered on the quality of the incoming solar radiation, by reducing mainly the irradiance in the ultraviolet band and reducing also the ratio between the irradiance in the red and far-red bands.

MATURAÇÃO DE UVAS MOSCATO GIALLO SOB CULTIVO PROTEGIDO 1

Plastic overhead cover (POC) is a recent viticulture practice in grapevine cultivation that maybe could changes the plant microclimate and the ripening profi le. The purpose of this work was to evaluate the POC infl uence on ripening evolution of grapes Moscato Giallo. The experiment was carried out in 2005/06 and 2006/07 seasons, in a vineyard covered with an impermeable plastic cloth (2.65 m x 160 m), being left fi ve rows without covering (control). Berries were collected (three replicates of 100 units for treatment) weekly in each area (POC and control). These berries were evaluated regarding to weight, diameter and must composition (pH, o Brix, titratable acidity, malic and tartaric content). At harvest it was characterized also the musts of covered and uncovered grapes ( o Brix, reduced sugar, relative density, total acidity, tartaric and malic content, pH and must yield). POC modifi es the microclimate in canopy and clusters infl uencing the grape ripening. Due to reduction of photosynthetically active radiation, that slows the sugar accumulation, the POC grapevines should be harvest after compared to conventional grapes. Index terms: plasticulture, microclimate, ripening, management.

Anatomy, chlorophyll content and photosynthetic potential in grapevine leaves under plastic cover

The present study evaluated the anatomy, chlorophyll content and photosynthetic potential of grapevine leaves grown under plastic cover. The experiment was carried out in vineyards of Moscato Giallo cultivar covered and uncovered with plastic. A block design with 10 selected plants was used for each area (covered and uncovered). Twelve leaves (six of them fully exposed to solar radiation and six grown under shaded conditions) were collected from each area and were fixed and analyzed microscopically (thickness of the adaxial and abaxial epidermis and of the palisade and spongy parenchymas). Chlorophyll content and photosynthetic potential were determined in the vineyard at veraison and after harvest. Plastic covering increased the thickness of the palisade parenchyma in exposed and shaded leaves due to solar radiation restriction. However, the leaves from the covered vineyard did not have the same response to the restriction of solar radiation, as observed in the uncovered vineyard. The thickness of the adaxial and abaxial epidermis and of the spongy parenchyma did not vary due to solar radiation restriction. Chlorophyll content increased in the leaves of covered plants. The photosynthetic potential of the vines is not affected by solar radiation restriction imposed by plastic cover due to anatomical modification in leaves.

Relações hídricas, rendimento e compostos fenólicos de uvas Cabernet Sauvignon em três tipos de solo

No presente trabalho, foi avaliada a influencia de tres tipos de solo (Argissolo Bruno-acizentado, Planossolo Haplico e Neossolo Regolitico) sobre aspectos quantitativos e qualitativos da producao de uvas destinadas a vinificacao. O experimento foi executado no ciclo 2008/2009, em vinhedo da cultivar Cabernet Sauvignon (Vitis vinifera L.), no municipio de Bento Goncalves, (RS). Avaliou-se a disponibilidade hidrica em base gravimetrica ao longo do periodo de maturacao das uvas, o potencial da agua na folha, parâmetros de crescimento vegetativo, componentes do rendimento e os compostos fenolicos no momento da colheita. Argissolos Bruno-acizentados propiciaram maior crescimento vegetativo, sobretudo em massa de ramos, comprimento de entrenos e area foliar, assim como, cachos com maior numero de bagas. Planossolos Haplicos com maior disponibilidade hidrica proporcionaram maior produtividade das videiras. Neossolos Regoliticos levaram a menor disponibilidade hidrica, o que reflete em reducao do potencial da agua na folha. Nestas condicoes de restricao hidrica, as videiras tiveram menor crescimento e rendimento, como tambem, maiores teores de taninos e indice de polifenois totais. Em geral, o Neossolo Regolitico pode ser considerado mais promissor para a obtencao de vinhos finos de qualidade.

Regulador de crescimento em plantas de trigo: reflexos sobre o desenvolvimento vegetativo, rendimento e qualidade de grãos

Reguladores de crescimento podem ser utilizados com o intuito de evitar o acamamento do trigo, porem, podem apresentar outros beneficios, em funcao da melhoria da interceptacao de luz e da realocacao de carbono. O objetivo deste trabalho foi avaliar a influencia do regulador de crescimento (trinexapac-etil) sobre o desenvolvimento vegetativo, os componentes da producao e a qualidade de graos de dois cultivares de trigo distintos em relacao a susceptibilidade ao acamamento. Um experimento foi realizado em casa de vegetacao e outro a campo. No experimento em casa de vegetacao, foram avaliadas as variaveis de desenvolvimento vegetativo (estatura de planta, relacao entre raiz e parte aerea, areas foliares unitaria e total, comprimento e materia seca de raizes) em plantas de trigo, com e sem a aplicacao de trinexapac-etil, em estadio de primeiro no visivel e segundo no perceptivel. A campo foram avaliadas variaveis de desenvolvimento vegetativo (clorofila, estatura e area foliar), rendimento (numero de espigas, massa de mil graos e produtividade) e qualidade (massa do hectolitro e conteudo de proteina), em plantas de trigo com variacoes de aplicacao de trinexapac-etil (testemunha sem aplicacao, perfilhamento e primeiro no visivel e segundo perceptivel). O regulador de crescimento trinexapac-etil aumenta a relacao entre raiz e parte aerea do cultivar Mirante e a produtividade dos cultivares Quartzo e Mirante. Porem, nao interfere na qualidade de graos desses cultivares.

Desempenho agronômico de canola em diferentes espaçamentos entre linhas e densidades de plantas

The objective of this work was to evaluate the agronomic performance of canola at different row spacing and plant densities. A randomized complete block design was used with four replicates in a split-plot arrangement. The plots consisted of row spacing (17, 34, 51 and 68 cm), and subplots consisted of plant densities (15, 30, 45 and 60 plants per square meter). The experiments were carried out in 2011 and 2012. Evaluations were done for: number of secondary, tertiary, and quaternary branches; number of pods on primary, secondary, tertiary, and quaternary branches; number of pods per plant; number of grains per plant; thousand grain weight; grain yield; apparent biological yield per plant; straw and grain yield per plant; and harvest index. The largest numbers of branches, pods per plant, and grains per plant, as well as the highest total mass of plants were obtained when using plant density of 15 plants per square meter. The highest grain yield per area is obtained when using 17 cm row spacing and plant density of 45 plants per square meter.

Soybean Architecture Plants: From Solar Radiation Interception to Crop Protection

The soybean plant architecture in relation to better solar radiation interception and pro‐ duction gain is an aspect that requires a better understanding, since soybean is an impor‐ tant crop worldwide. The genetic traits, management and environmental conditions are points that further extend the range of issues on crop productivity. The light quality is measured by the red/far‐red (R/FR) ratio (R ∼ 660 nm, FR ∼ 730 nm). This affects the plant growth and morphological developments in different ways. The plant leaves change their angle during the day to better intercept radiation. This heliotropic movement and some computational models together have been used to enhance some agricultural prac‐ tices. Soybean plant is dependent on the interaction between genotype and environment. Thus, the enhanced understanding in relation to photosynthetic activity, grain yield by light interception efficiency and culture protection managements in soybean are covered.

Cultivo protegido de videira: manejo fitossanitário, qualidade enológica e impacto ambiental

The protected cultivation of grapes is an alternative to reduce the incidence of fungal diseases in regions with excess rainfall. The use of plastic covering on vine planting rows produces changes in the microclimate around the plant, due mainly to the absence of freely available water on leaves and berries. These changes hinder the development of fungal diseases, such as bunch rot - currently one of the biggest challenges in disease control in traditional grape growing regions like Serra Gaucha - and reduce fungicide use. However, powdery mildew, whose incidence under high relative humidity conditions is usually low, must be closely monitored in protected cultivation. Also, fungicides must be used with caution as plastic covering reduces the incidence of ultraviolet radiation and rainfall on clusters, thereby increasing the residual effect of fungicides. The higher accumulation of fungicide on grapes directly affects their in natura consumption and compromises yeast fermentation during the winemaking process. In general, plastic covering is efficient in controlling fungal diseases and in reducing fungicide use, but it must be regarded as a new cultivation system as it requires distinct disease control compared to conventional cultivation. The used plastic covering must be regarded as crop residues, demanding specific precautions against environmental contamination.

Properties of the enzyme acetolactate synthase in herbicide resistant canola

Bragantia, Campinas, v. 77, n. 3, p.485-492, 2018 ABSTRACT: Mutations in the gene that encodes the enzyme acetolactate synthase (ALS), conferring plant resistance to ALS inhibitor herbicides, can reduce or inhibit enzymatic function. The objective of this work was to determine the functionality and kinetic characteristics of the enzyme ALS and evaluate the action of the herbicides imazapic (imidazolinone) and metsulfuron-methyl (sulfonylurea) on the activity of the enzyme ALS in canola hybrid Hyola 571CL (imidazolinone resistant), compared to hybrids Hyola 555TT (triazine resistant) and Hyola 61 (conventional). The plants were grown in a greenhouse, and leaves were collected to perform ALS activity analysis. The concentration of pyruvate to provide initial velocity equal to half the maximum reaction rate (Km) and the maximum PLANT PROTECTION Article

Root growth and productivity of conventional and herbicide-tolerant canola in contrasting environments

The canola (Brassica napus L. oil variant) is considered as a winter crop alternative in south Brazil. Thus, the aim of this study was to compare the root growth and the productivity components of hybrid grains of conventional and herbicide tolerant canola in different localities. The experiments were conducted in the municipality of Passo Fundo, Rio Grande do Sul state and Guarapuava, Paraná state, Brazil. The randomized block design with four replication was used. The genotypes evaluated were: Hyola 61 and H92002 (conventional), Hyola 571 CL and K10050 (imidazolinone-resistant), and Hyola 751 TT (triazine-resistant). In order to evaluate the root system, soil monolith were collected and image analysis measuring the superficial area and the total root volume of the sample in diameter classes, root density and specific surface area were done. The grains productivity components and the number of branches in the plant were measured through the number of siliques in the branches. The productivity of the grains and the thousand grain mass were measured as well. The canola hybrid presented higher root length, surface area and volume in the diameter scale between 1 and 5 mm of density. In addition, there were variations in the growth of roots and grain productivity in different environments, in which imidazolinone-tolerant hybrids presented higher development of the roots, as well as, higher grain productivity in the different environment studied.