ABSTRACT Chill is a limiting factor in commercial production of temperate fruit due to their dormancy mechanism. Thus, knowledge of chill requirements of cultivars is important to reach successful production. This study aimed at evaluating responses given by different pecan cultivars subject to artificial chill. Pecan branches were collected from twelve 9-year-old cultivars – Success, Shoshoni, Farley, Elliott, Mohawk, Jackson, Desirable, Barton, Importada, Shawnee, Choctaw and Melhorada – in two orchards located in Canguçu, Rio Grande do Sul (RS) state, Brazil, in 2017 and 2018. Treatments consisted in exposing branches to 0, 250, 500, 750 and 1,000 chill hours in a cold chamber (4.0 ± 0.5 °C) and then taking them to the germination chamber (25 ± 0.5 °C and photoperiod of 16 hours of light) until the end of the evaluations. Final budbreak rate (FBR) of every cultivar and the number of days required to reach 50% of budbreak (DD50%) were evaluated. Chill required by cultivars to start budbreak varied in both years under evaluation. Both FBR and DD50 were higher in 2017 than in 2018. Due to high variation in FBR and DD50, chill requirements of pecan cultivars could not be clearly determined by the biological method.

RESUMO A fitorremediação é uma técnica que utiliza plantas, associada ou não com amenizantes de solo para descontaminar áreas contaminadas. O objetivo do trabalho foi avaliar o uso de turfa e Erythrina crista-galli na fitorremediação de solo contaminado com cobre. O trabalho foi desenvolvido em casa de vegetação por 120 dias, utilizando o delineamento experimental inteiramente casualizado, com seis repetições, em arranjo fatorial (2 x 6): com ausência e presença de turfa (200 mL L-1 de solo) e seis doses de cobre no solo (0, 60, 120, 180, 240, 300 mg kg-1).Os parâmetros avaliados foram: altura das mudas, diâmetro do colo, massa seca radicular e aérea, teores e quantidade acumulada de cobre no sistema radicular e parte aérea, índices de qualidade de Dickson, de tolerância e de translocação. Os resultados evidenciaram que a adição de turfa estimulou o crescimento das mudas de Erythrina crista-galli, porém não agiu como amenizante da contaminação do solo com o cobre. A Erythrina crista-galli apresentou baixo potencial fitoextrator de cobre.

ABSTRACT Phytoremediation is a technique that uses plants, associated or not with soil alleviation for the recovery of contaminated areas. The aim of this study was to evaluate the use of peat and Erythrina crista-galli in the phytoremediation of soil contaminated with copper. The work was conducted in a greenhouse for 120 days using a completely randomized design with six replications in a factorial arrangement (2 x 6): with absence and presence of peat (200 mL L-1 soil) and six doses the copper (0, 60, 120, 180, 240, 300 mg kg-1). The parameters evaluated were: seedling height, the stem diameter, root and shoot dry weight, the levels and the cumulative amount of copper in the root system and aerial part, the quality indices of Dickson, tolerance and translocation. The results showed that the addition of peat stimulated the growth of Erythrina crista-galli seedlings but did not act as a mitigation of soil contamination with copper. Erythrina crista-galli showed low copper phytoextraction potential.

Abstract Pecan trees require adequate soil moisture conditions to produce nuts with good yield and quality. Irrigation should be an important considered practice in orchards management plan, mainly in regions with water deficit periods. The objective of this research was to evaluate irrigation on pecan nuts growth and yield. This study was conducted in Uruguay, during the fast development phase until the pecan nuts harvest. Three irrigation treatments were used: 0 L (control), 70 L and 140 L plant-1 of water every two days, applied via drip irrigation in seven-year-old pecan trees of the cultivar Success. The number of nuts per cluster and nuts’ diameter and length were evaluated during nut growth. After harvesting, peeled nuts’ width and length were measured, and after peeling, the kernel length, width, height and filling and the kernel and peel percentage were evaluated. According to the results, it was possible to identify that periods of water deficit during pecan nuts development affected the kernel filling stageand size. Irrigation in pecan plants provides greater dimensions and nuts mass. With the use of 140 L plant-1, there was an increase in the nut mass of more than 100% in relation to the nuts from plants without irrigation.

Abstract Blackberry is a species which has high potential to grow in an organic production system. However, there is scarce information on the behavior of cultivars and selections of this species conducted in an ecologically based system, a fact that makes it difficult to recommend cultivars for this production system. This study aimed to evaluate and characterize the phenology and productive aspects of six blackberry genotypes grown in an organic system, in Pelotas, Rio Grande do Sul (RS) state, Brazil. Evaluation of the following variables was carried out in the three first production cycles (2015-2016, 2016-2017 and 2017-2018): phenology, number of fruits.plˉ¹, mean fruit yield.plˉ¹, yield (kg.haˉ¹), mean fruit mass (g) and soluble solid content (° Brix). Regarding phenology, genotype Black 112 was later than the others whereas Black 178 was the most precocious one. In the last year under evaluation, genotypes yielded around 10 ton.haˉ¹, except Black 128 selection, which yielded approximately 6,767 ton.haˉ¹. Genotypes Black 178, Black 112 and Black 145 and both cultivars BRS Xingu and Tupy exhibited potential to grow in an organic production system.

Abstract This study aims to evaluate the effect of substrates and container content on growth and quality of Peltophorum dubium seedlings. The design was completely randomized in a factorial arrangement (2 × 9), with two containers sizes (125 cm3 and 280 cm3) and nine substrates formulated from the mixture of subsoil (S), vermicompost (V) and commercial substrate (CS), in the following proportions (v:v): S100, V100, CS100, S75 + V25, S50 + V50, S25 + V75, CS75 + V25, CS50 + V50 and CS25 + V75, with nine replicates. We assessed seedling height, stem diameter, root and shoot dry matter, height/shoot dry matter ratio; Dickson quality index; and percentages of nitrogen, phosphorous and potassium in the shoot. The use of the 125 cm3 dibble tube containing 100% vermicompost allowed for higher quality of Peltophorum dubium seedlings.

Abstract In producing forest seedlings, the use of residues may be an option to improve seedling quality. Thus, the objective of this study was to evaluate the initial growth and quality of Toona ciliata seedlings on different substrates. The experimental design was completely randomized with seven treatments consisting of commercial substrate (CS), vermicompost (VC), urban waste compost (UWC) and mixtures in proportions of 50% (CS + VC, CS + UWC and VC + UWC) and 33% (CS + UWC + VC), with twelve replications. The use of substrates composed of organic residues 120 days after sowing shows potential for producing Toona ciliata seedlings. The combination of substrate components provides higher seed growth and quality than unmixed substrates. Compositions of 50% UWC or 50% VC + 50% CS are efficient in growth and seed quality.

ABSTRACT This study evaluated the effect of different sources of organic fertilizer and their most appropriate proportions to produce Toona ciliata seedlings. Broiler litter and cattle manure were used as organic fertilizer at four proportions in the substrate (0, 15, 30, and 45%). A control treatment was adopted with 6 kg controlled-release fertilizers (m-3 substrate). The following parameters were assessed: germination, seedling height, stem diameter, and shoot and root dry matter, as well as the Dickson Quality Index. Cattle manure did not provide satisfactory results, whereas the use of broiler litter in the substrate resulted in seedling development similar to that of the control treatment. In conclusion, concentrations up to 30% of broiler litter can be recommended to substrate composition, and greater proportions of this compound (>30%) preclude seed germination.

A contaminação do solo com zinco (Zn) tem aumentado necessitando-se de técnicas para minimizar o seu efeito tóxico. O objetivo do trabalho foi determinar a influência da turfa no crescimento e tolerância de Erythrina crista-galli L. a solo contaminado com Zn. O trabalho foi conduzido em estufa por 120 dias, utilizando delineamento experimental inteiramente casualizado em arranjo fatorial (2 x 6): solo (com e sem turfa) e seis doses de Zn (0, 200, 400, 600, 800, 1000 mg kg-1). Avaliou-se a altura das plântulas, diâmetro do colo, massa seca radicular e aérea, os teores e a quantidade acumulada de zinco no sistema radicular e na parte aérea, índice de qualidade de Dickson, índice de tolerância e índice de translocação. Os resultados evidenciaram que o Zn reduziu os parâmetros morfológicos da E.crista-galli.A espécie E. crista-galli apresentou maior translocação de Zn com 200 mL de turfa L-1 de solo, porém com tolerância moderada ao Zn.

The quantity of soil contaminated with zinc (Zn) is increasing and management practices should be implemented to minimize its toxic effect. The objective of this work was to determine the influence of peat on the growth and tolerance of Erythrina crista-galli L. to soil contaminated with Zn. The study was conducted in a greenhouse for 120 days, using a completely randomized design in a factorial arrangement (2 x 6): soil (with and without peat) and six doses of Zn (0, 200, 400, 600, 800, 1000 mg kg-1). We evaluated the seedling height, stem diameter, root and shoot dry weight matter the levels and the cumulative amount of Zn in the root system and aerial part, Dickson quality index, tolerance index and translocation index. The results showed that zinc reduces the morphological parameters of E. crista-galli.Erythrina crista-galli had more translocation of Zn with 200 mL of soil L-1 peat, but has moderate tolerance to Zn.

RESUMO A fitorremediação é uma técnica que usa plantas associadas ou não a agentes de melhoramento, para fitoestabilização em solo contaminado. O objetivo deste estudo foi avaliar o uso de Senna multijuga associada à turfa em fitoestabilização de cobre em solo contaminado. O experimento foi conduzido em casa de vegetação durante 120 dias, usando-se o delineamento inteiramente casualizado em esquema fatorial (2 x 6), com e sem turfa (200 mL L-1 de solo) e seis doses de cobre (0, 60, 120, 180, 240, 300 mg kg-1), com seis repetições por tratamento. Avaliaram-se, aos 120 dias após a semeadura, as plantas quanto à altura, ao diâmetro, massa seca radicular e aérea, conteúdo e quantidade acumulada de cobre no sistema radicular e na parte aérea; índice de qualidade de Dickson, índice de tolerância e de translocação também foram analisados. Os resultados mostraram que a utilização de 200 mL de turfa L-1 de solo não foi eficaz como agente melhorante para solo contaminado por cobre, mas atuou como condicionador do solo aumentando os parâmetros morfológicos de Senna multijuga. A espécie Senna multijuga apresentou baixo potencial de fitoestabilização de cobre em solo contaminado, em seu período inicial de desenvolvimento.

ABSTRACT Phytoremediation is a technique that uses plants, whether associated or not to ameliorating agents, for phytostabilization of contaminated soil. The aim of this study was to evaluate the use of Senna multijuga associated with peat in the phytostabilization of copper contaminated soil. The experiment was carried out in a greenhouse for 120 days, using an entirely randomized design in a factorial arrangement (2 x 6), with and without peat (200 mL L-1 soil) and six doses of copper (0, 60, 120, 180, 240, 300 mg kg-1), with six repetitions of each treatment. At 120 days after seedling, the plants were evaluated for height, stem diameter, root and aerial dry matter, contents and accumulated amount of copper in the root system and aerial part. Also, the Dickson quality indexes, as well as tolerance and translocation indexes were analyzed. The results showed that the use of 200 mL of peat L-1 of soil was inefficient as an ameliorating agent for copper-contaminated soil, but it acted as a soil conditioner, increasing the morphological parameters of S. multijuga. In its initial development period, the S. multijuga species presented low copper phytostabilization potential in contaminated soil.

RESUMOConcentrações elevadas de cobre (Cu) podem ser tóxicas às plantas; contudo, algumas espécies podem ser tolerantes a solo contaminado por este metal. Objetivou-se avaliar, no trabalho, a translocação e a tolerância de Cu em mudas de timbaúva, pata-de-vaca e amendoim-bravo submetidos a solo contaminado com o referido metal. O trabalho foi conduzido em casa de vegetação por 120 dias utilizando-se, como substrato, um Latossolo Vermelho com textura argilosa. O delineamento experimental foi inteiramente casualizado em arranjo fatorial (3 x 6), sendo três espécies florestais (timbaúva, pata-de-vaca e amendoim-bravo) e seis doses de Cu no solo (0, 60, 120, 180, 240 e 300 mg kg-1), com seis repetições. Foram avaliados a massa seca total, os teores e a quantidade acumulada de Cu no sistema radicular e, na parte aérea, índice de tolerância, índice de translocação e o coeficiente de impacto no teor relativo. A timbaúva evidenciou menor redução da massa seca total com a elevação das doses de cobre no solo indicando ser uma espécie capaz de diminuir a translocação do metal para a parte aérea e tolerar doses de até 236 mg kg-1 do metal no solo. As mudas de timbaúva são mais tolerantes à contaminação do solo com cobre que as de amendoim-bravo e pata-de-vaca.

ABSTRACTHigh concentrations of copper (Cu) may be toxic to plants, yet some species can be tolerant to soils contaminated by this metal. The study aimed to evaluate Cu translocation and tolerance in seedlings of ‘timbaúva’ (Enterolobium contortisiliquum (Vell.) Morong), ‘pata-de-vaca’ (Bauhinia forficata Link) and ‘amendoim-bravo’ (Pterogyne nitensTul) subjected to Cu-contaminated soil. The study was conducted in a greenhouse for 120 days, using as substrate a clayey Oxisol. The experiment was set in a completely randomized design, using a 3 x 6 factorial scheme, corresponding to three forest species (‘timbaúva’, ‘pata-de-vaca’ and ‘amendoim-bravo’) and six Cu doses in the soil (0, 60, 120, 180, 240 and 300 mg kg-1), with six replicates. The following variables were analysed: total dry matter, Cu content and its accumulation in roots and shoots, tolerance and translocation indices and the coefficient of impact of the contamination on the relative contents of Cu in roots and shoots. ‘Timbaúva’ showed lower reduction in total dry matter with the increase of Cu doses in the soil, proving to be able to decrease Cu translocation to the shoots and tolerate doses of up to 236 mg kg-1 of this metal in the soil. ‘Timbaúva’ seedlings are more tolerant to contamination of Cu in soil, compared with seedlings of ‘amendoim-bravo’ and ‘pata-de-vaca’.