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Objetivando a determinação do período de produção de laranjas no município de Eldorado do Sul, Depressão Central do Rio Grande do Sul, foram avaliados parâmetros de maturação de seis cultivares de laranjeiras-doces. O estudo foi realizado durante 6 anos, de 1992 a 1997, com as cultivares, Rubi, Hamlin, Tobias e Pêra-Rio, durante 4 anos com 'Valência' e 3 anos com 'Folha-Murcha', na coleção de citros da Estação Experimental Agronômica da Universidade Federal do Rio Grande do Sul (UFRGS), situada em Eldorado do Sul-RS, à latitude 30degrees39'S e longitude 51degrees06'W, em solo Podzólico Vermelho Amarelo. Quinzenalmente, com início em abril e término em março, foram colhidas amostras de 20 frutos de 5 plantas de cada cultivar; a coleta de amostras começou no início da mudança de coloração da casca do fruto de verde para amarelo. Após a amostragem, os frutos foram acondicionados em sacos de polietileno e armazenados durante 1 a 5 dias a temperaturas entre 4 e 7masculineC, até serem analisados, para determinação dos teores percentuais da relação suco/bagaço, sólidos solúveis totais (SST), acidez total titulável (ATT) e relação SST/ATT. A colheita pode ser iniciada na 2feminine quinzena de abril, com laranjas-'Hamlin' e prolongar-se até a 2feminine quinzena de fevereiro, com laranjas-'Folha-Murcha'. As laranjas-'Hamlin' podem ser colhidas desde a 2feminine quinzena de abril até a 1feminine quinzena de outubro; as laranjas-'Rubi' desde a 1feminine quinzena de maio até a 2feminine quinzena de setembro; as laranjas-'Tobias', desde a 1feminine quinzena de julho até a 1feminine quinzena de novembro; as laranjas-'Pêra-Rio' desde a 2feminine quinzena de agosto até a 1feminine quinzena de fevereiro; as laranjas-'Valência' desde a 2feminine quinzena de agosto até a 1feminine quinzena de janeiro e as laranjas-'Folha-Murcha' desde a 1feminine quinzena de setembro até a 2feminine quinzena de fevereiro.

This study evaluated the influence of frequency and intensity of pruning on young orchards, with organic management system, on the yield and fruit quality of 'Valencia' oranges. The trees were budded on Poncirus trifoliata rootstock and implanted in August, 2001, in Montenegro-RS. The pruning tested was: 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. The total fruit mass production was registered and the average weight fruit in the crops 2006, 2007 and 2008 was determined. The fruit quality, total soluble solids (TSS), total acids concentration (TTA) and ratio (TSS/TTA) were assessed. In orchards with fewer than seven years old, the pruning does not change the cumulative yield for three seasons, the fruit quality and its physical-chemical properties. The frequencies and intensities of pruning reduce the yield in the year after pruning. [ABSTRACT FROM AUTHOR]

An experiment was carried out to assess the physical and chemical evolution of three substrates and their relation to the vegetative development of seedlings of citrus rootstock, cultivated in containers. The experiment was carried out in greenhouse conditions on 27 September 2001 and continued until 120 days after sowing. The experimental design was randomized block in a split-plot scheme. In the plots, there were tested substrates: two of them were specialized for horticulture (commercial 1 and 2) and a mixture (turf plus carbonized rice husk). In the subplots, there were four citrus rootstocks (Trifoliate orange, "C13" Citrange, "C37" Citrange, and "Rangpur" Lime). The main results showed that the physical characteristic of the substrate that had undergone the most modification during cultivation was the remnant water; the chemical characteristics of the substrate were determined for the proper development of the rootstocks, with high salinity being harmful. The nutrient availability, before and after cultivation, must be adjusted to the capacity of each of the citrus rootstock to absorb. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 150mL 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. [ABSTRACT FROM AUTHOR]

'Michal' tangerine (Citrus clementina x C. tangerina) can be a good choice as canopy for early maturing fruit production in Rio Grande do Sul. The limitation is the lack of information about its performance and management. The aim of this research was to evaluate the development, production and fruit quality of 'Michal' tangerine grafted on five rootstocks: 'Troyer' citrange, 'Swingle' citrumelo, 'Cravo' lemon, 'Sunki' tangerine and 'Flying Dragon' trifoliate orange, in the Depressão Central of Rio Grande do Sul. The following variables were evaluated: plant height; trunk circumference; canopy projection area (APC); produced fruit number and weight (MF); MF/APC relation (IP); juice total soluble solids (SST) and total titrable acidity (ATT); fruit size and juice content. 'Swingle' citrumelo provided good vigor, yield, IP, SST and ATT for 'Michal', while 'Cravo' lemon induced good vigor, yield, IP and fruit size. Both are good recommendations as rootstock for orchards of 'Michal'. [ABSTRACT FROM AUTHOR]