Otto Carlos Koller

Influência de fungos micorrízicos arbusculares sobre o desenvolvimento vegetativo de porta-enxertos de abacateiro

Resumo n O objetivo deste trabalho foi verificar a influŒncia da inoculaAao de seis espOcies de fungos micorrIzicos arbusculares (FMA) (Glomus clarum, Scutellospora heterogama, Glomus etunicatum, Acaulospora scrobiculata, Gigaspora margarita e Glomus manihotis) no desenvolvimento vegetativo, nutriAao mineral e conteœdo de subst‚ncias de reserva em porta-enxertos de abacateiro (Persea†sp.), oriundos de caroAos. Os porta-enxertos foram cultivados em casa de vegetaAao com cobertura de sombrite (70%) e acondicionados em sacos de polietileno preto (5†L), contendo substrato constituIdo de solo†+ areia†+ resIduo decomposto de casca de acAEcia-negra (Acacia mearnii) (2:2:1, v:v:v). Dois meses apUs a infecAao das pl‚ntulas com FMA (30 g/pl‚ntula), observou-se que a dependŒncia do abacateiro aos FMA variou com a espOcie de fungo em estudo. Scutellospora heterogama, Acaulospora scrobiculata e Glomus etunicatum proporcionaram melhor nutriAao, maior conteœdo em subst‚ncias de reserva e maior desenvolvimento vegetativo das plantas. Glomus clarum somente incrementou a altura das plantas. A infecAao com Glomus manihotis nao alterou o desenvolvimento vegetativo dos porta-enxertos, e Gigaspora margarita foi prejudicial. Termos para indexaAao: endomicorrizas, inoculaAao, nutriAao das plantas, etapas de desenvolvimento da planta. Influence of arbuscular mycorrhizal fungi on vegetative growth of avocado rootstocks

Aspectos técnico-ambientais da produção orgânica na região citrícola do Vale do Rio Caí, RS

Ha uma preocupacao crescente sobre a necessidade de producao e consumo de alimentos mais saudaveis, sem uso de agrotoxicos nem fertilizantes sintetico-industriais. Neste contexto se insere a pratica da agricultura orgânica, que, contudo, apresenta resultados ainda pouco avaliados nos meios academicos e cientificos. Assim, pretendeu-se nesta pesquisa diagnosticar aspectos tecnico-ambientais da producao orgânica na regiao citricola do Vale do Rio Cai, no Rio Grande do Sul. Inicialmente, foram selecionadas propriedades de oito agricultores familiares, todas ja convertidas ao sistema orgânico de producao, sendo aplicadas entrevistas semi-estruturadas. Os produtores mostram-se satisfeitos com o sistema orgânico de producao e revelam bom conhecimento sobre o ambiente, plantas, solos e processos agroecologicos, adquiridos atraves da participacao em eventos tecnicos e em reunioes da Cooperativa Ecocitrus. A constante troca de experiencias entre esses agricultores tem melhorado sua qualificacao tecnica, alem de melhor conscientiza-los nos aspectos politicos, economicos e sociais.

Propagação vegetativa de abacateiro por estaquia

With the objetive to propagate avocados vegetatively by means of stem cuttings, branches of cultivars Ouro Verde and Baronesa were forced to etiolate. Grafted avocado plants were prunned 10 cm above of the grafting point. Half of those plants were covered with black polyethylene and placed in a darkroom. The other half of those plants were transfered to a greenhouse. The branches formed were girdled at the base. One month after the plants had been pruned, stem cuttings 20 cm length, with 4 mature leaves, were taken from each plant. These stem cuttings were imersed in a 2000 mg L-1 indolbutiric acid (IBA) solution for 10 seconds and placed, singly, in 500ml black plastic bags, containing carbonized rice husk. After 2 months, they were transfered to 5 L black polyethylene bags. At the moment of transplant, 62.5% and 12.5%, of etiolated and non etiolated branches of cv. Ouro Verde, respectively, had formed roots. Cv. Baronesa did not emit roots in any situation. After transplanting, the percentage of root formation on cv. Ouro Verde stem cuttings remained the same, increasing, however, the total number of roots. For Cv. Baronesa, non etiolated stem cuttings had 12.5% of root formation, while the etiolated ones continued without root formation.

Vegetative growth of Poncirus trifoliata L. Raf. inoculated with mycorrhizal fungi in three growing media

ABSTRACT The experiment studies three different growing media [soil + sand (1:1); soil + sand + carbonated rice husks (1:1:1); soil + sand + decomposed Acacia bark (Acacia mearnsii) after tanin extration (1:1:1)] and inoculation of two species of Arbuscular Mycorrhizal Fungi (AMF) (Glomus clarum and Glomus etunicatum) effects on the vegetative growth of Poncirus trifoliata L. Raf. Initially, seedlings were cultivated under greenhouse conditions for 145 days, with seedlings growing in alveolated styrofoam trays with 150 mL alveoli. Subsequently seedlings were transplanted into 5-L black plastic bags. The growing media were chemically and physically characterized. The most appropriate substrate for the growth of Poncirus trifoliata was “soil + sand + decomposed Acacia bark”, due to superior chemical and physical properties and possibly due to the unexpected presence of indigenous AMF observed in this substrate, resulting from the lack of previous sterilization of decomposed Acacia bark. The inoculation with two species of AMF did not significantly altered the Poncirus trifoliata vegetative growth during the alveolated styrofoam trays phase; however, when the plants were cultivated in 5-L plastic bags, those inoculated with Glomus clarum had a higher relative growth.

Produção de frutos e incidência de cancro cítrico em laranjeiras "Monte Parnaso" enxertadas sobre sete porta-enxertos

Citrus rootstocks can exert some influences on fruit production and susceptibility of the plants to citrus canker (CC). This research was performed aiming to select rootstocks which induce higher productivity index and lower susceptibility of ‘Monte Parnaso’ navel orange (Citrus sinensis) trees to the bacteria Xanthomonas axonopodis pv. citri. The research was carried out in an experimental orchard, with ten-years-old trees, planted at spacement of 2.5m between trees and 6.0m between rows, located in Butia city, in the Central Depression of Rio Grande do Sul state. It was used an randomized blocks experimental design, with 7 treatments and 4 replications. The treatments consisted of the following rootstoks: Rangpur lime (C. limonia.), ‘Volkameriana’ lemon (C. volkameriana.), ‘Flying Dragon’ trifoliata orange (Poncirus trifoliata), ‘Caipira’ orange (C. sinensis), ‘troyer’ citrange (C. sinensis x P. trifoliata), ‘Sunki’ tangerine (C. sunki.) and ‘Swingle’ citrumelo (C. paradisi x P. trifoliata). The parameters evaluated were: number of fruits and leaves with citrus canker lesions per plant and at two previously selected and marked branches per plant, at different times . The results revealed that the ‘Swingle’ citrumelo and ‘Flying dragon’ rootstocks induced the highest productivity index and, the lowest incidence of citrus canker disease on leaves and fruits. ‘Rangpur’ lime and ‘Volkameriana’ lime rootstocks, promoted a heavy crop load, however, showed higher susceptibility to citrus canker disease.

Effect of arbuscular mycorrhizae on cv. carmem avocado plants

The effects of six species of arbuscular mycorrhizae (AM) on root colonization, nutrient uptake, reserve substances, and vegetative development of cv. Carmem avocado (Persea sp.) plants were evaluated. Glomus clarum Nicol. and Schenck, Glomus etunicatum Becker and Gerd, Glomus manihotis How, Siev and Schenk; Acaulospora scrobiculata Trappe, Scutellospora heterogama Nicol and Gerd and Gigaspora margarita Becker and Hall were inoculated on avocado seedlings, onto which Carmem scions were grafted. Responses of the avocado plants to the different AM species 7 months after grafting were distinctly different. Scutellospora heterogama, A. scrobiculata, G. etunicatum, and G. clarum more thoroughly colonized the root system of the avocado plants, resulting in enhanced nutrient uptake and higher accumulation of reserve substances, which favored vegetative growth. The mutualism between avocado plants and G. margarita or G. manihotis was not efficient under the conditions of the present experiment. *Part of the dissertation of the first author towards the degree of Master of Science.

Identificação e análise da cadeia de distribuição das frutas cítricas de mesa sem sementes: um estudo de caso na cidade de São Paulo

This research aims at identifying commercial mechanisms for in nature seedless citric fruits which are produced in Sao Gabriel, Santa Margarida do Sul and Rosario do Sul, cities located in the north boundary of the southern half of the state of Rio Grande do Sul. The research method consisted of an exploratory case study, in which ten traders were interviewed in Sao Paulo city. It has been noticed that in Sao Paulo there are traders who import citric fruit from Uruguay and Spain in order to supply the domestic market, and most of them would like to replace such imports for fruits produced in Brazil as long as similar quality and lower prices can be achieved. The CEAGESP (Food Supply Distribution Center) is the establishment that, in a single place, accounts for the highest volume of fruit distribution. In this study the configuration of the distribution chain of seedless citric fruits was set up.

Produção e qualidade físico-química de frutos de laranjeiras 'Valência' em diferentes intensidades e frequências de poda

ABSTRACT - The pruning in citrus can be applied with the objective to control vegetative growth and renew fruiting branches. This research aimed to evaluate different manual pruning regimes in young orchards of ‘Valencia’ Orange, grown in conventional management. It was used an orchard with spacing 5.0 x 2.5 m, established in 2001 at Montenegro–RS, Brazil. The treatments, starting in 2004, were: A - control, without pruning; B - annual pruning of 15%; C - biennial pruning of 15%; D - biennial pruning of 30% and E - three-year 30% pruning of the canopy volume. The experiment had a randomized complete-block design, with four-trees plots and four replications. It was evaluated the number of fruits, total fruit mass production and average weight fruit in the crops 2006, 2007 and 2008. Aspects relating to fruit quality, total soluble solids (TSS), total titratable acidity (TTA) and ratio (TSS/TTA) on juice were assessed. The manual pruning does not alter significantly the cumulative yield of three crops, nor physical-chemical and fruits quality in orchards of ‘Valencia’ orange under the age of seven, with conventional management system.

Propagação de abacateiro via estacas estioladas

This research aimed to test a method of avocado propagation from etiolated cuttings in recipients with different heights. The experiment was carried out in an intermittent mist chamber. The experimental design was in randomized blocks with a 3x4 factorial and three replicates. Two methods of sap obstruction (girdling or strangulation) and four heights of containers (10, 15, 20 or 25 cm) were tested. After 250 days, there was no effect of container heights on the survival, the number of developed leaves, plant height and diameter of the seedlings formed from etiolated cuttings. There was a higher survival rate and number of leaves in girdled cuttings as compared to control plants; cuttings obtained from the strangulation treatment had intermediate behavior. The previous bark girdling or strangulation of etiolated avocado branches increased survival and plant growth for the propagation of selection Viamao cuttings.

Controle químico do cancro cítrico em plantas jovens sob manejo convencional e orgânico

The objective of the present work was to evaluate the development of the citrus rootstock Poncirus trifoliata, severity of citrus canker, caused by Xanthomonas citri pv. citri and the control of this disease with copper sprays, in conventional and organic management systems, at the Centro de Formacao da EMATER, located in Montenegro, Rio Grande do Sul. Plants were artificially inoculated with the bacteria. To control citrus canker, different sources of copper as well as concentrations and number of sprays were tested. In the organic system the bordeaux mixture was applied while in the conventional system copper oxichloride was sprayed. Plants trunk diameter, dry matter of the rootstocks and number of canker lesions on leaves and branches were evaluated in both systems. Citrus canker incidence on the rootstocks was equally intense, and the seedlings development was similar in both systems, but the budded plants grew better at the conventional system. Copper treatments were not effective in controlling citrus canker at the rootstocks due the high inoculum concentration. On the budded plants, with low inoculum concentration, both the Bordeaux mixture and the copper oxichloride controlled the disease, and the better treatments were when 0.3% metallic copper was applied with interval of 14 days. To improve citrus canker control by Bordeaux mixture on organic systems, there is a need of efficient control strategies of the citrus leaf miner.