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- A poda de manutenção em citrinosPublication . Matias, Pedro; Mendonça, Angélica; Oliveira, Silvino; Reis, Valter; Duarte, AmilcarA poda em citricultura é muitas vezes tema de discórdia: enquanto uns a consideram uma prática essencial ou mesmo indispensável, outros acham que é uma prática desnecessária, cujos benefícios não compensam os custos. Na realidade, se realizada da forma e na época adequada, a poda pode funcionar como estratégia para melhorar a produtividade e qualidade da produção, além de atenuar vários problemas da cultura dos citrinos.
- Citrus Pruning in the Mediterranean climate: a reviewPublication . Matias, Pedro; Barrote, Isabel; Azinheira, Gonçalo; Continella, Alberto; Duarte, AmilcarPruning is a common practice in citrus for various reasons. These include controlling and shaping the canopy; improving phytosanitary health, productivity, and fruit quality; and facilitating operations such as harvesting and phytosanitary treatments. Because pruning is an expensive operation, its need is sometimes questioned. However, it has been proven to be particularly important in Mediterranean citriculture, which is oriented towards producing fruits for a high-quality demanding fresh market. Herein, we summarize and explain the pruning techniques used in Mediterranean citriculture and refer to the main purposes of each pruning type, considering citrus morphology and physiology.
- Projeto PodaCitrus. Dados preliminares de dois ensaios de poda em laranjeiraPublication . Matias, Pedro; Oliveira, Silvino; Mendonça, Angélica; Barrote, Isabel; Duarte, AmilcarOs citrinos têm tendência para formar copas de grande dimensão, com formação de folhagem densa na periferia, o que limita a intensidade luminosa no interior da copa. Nestas condições, os ramos situados no interior acabam por secar e propiciar o desenvolvimento de fungos, ficando a zona produtiva da árvore limitada à zona exterior da copa. Para prevenir estes problemas é necessário realizar uma poda periódica de manutenção. Nas cultivares serôdias de laranjeira, o ciclo de desenvolvimento do fruto é superior a um ano. Por isso, as árvores têm sempre fruta. Nestes casos, a poda acarreta uma perda de produção e faz com que os agricultores a evitem ou que a façam de forma insuficiente. O projeto PodaCitrus visa a otimização da poda de citrinos, com vista à melhoria da qualidade da produção e à diminuição da incidência de doenças que afetam o aspeto do fruto. No âmbito deste projeto foram instalados dois ensaios de poda em laranjeiras serôdias (‘Valencia Late’ e ‘D. João’), em dois pomares, situados na freguesia de Luz de Tavira, concelho de Tavira, onde tinha havido uma poda insuficiente nos últimos anos. Com uma poda severa, feita entre o final de outubro e início de novembro de 2019, aumentou-se a intensidade luminosa no interior da copa e promoveu-se a sua renovação. Na colheita de 2020 observou-se uma redução da produção nas árvores podadas, sem que tenha havido aumento do calibre dos frutos. Estes resultados eram esperados, visto que os frutos já estavam em crescimento na época em que foi feita a poda. É de esperar que na colheita de 2021 haja um aumento de calibre do fruto nas árvores podadas. Num dos pomares, em dezembro de 2020, o diâmetro dos frutos das árvores podadas era superior ao dos frutos das testemunhas.
- A poda de citrinosPublication . Matias, Pedro; Duarte, AmilcarA produção citrícola apresenta grande importância na agricultura, a nível nacional e sobretudo na região do Algarve. Em 2020, a superfície cultivada de citrinos era 21 481 ha e a produção total de citrinos no Algarve foi 87% da produção total nacional, que atingiu 422 929 t (INE, 2021). Nas últimas décadas a citricultura tem passado por um processo de modernização tecnológica que permitiu aumentar a produtividade e a qualidade do fruto. Mesmo assim, permanecem alguns problemas, entre os quais, a alternância de produções e o aparecimento de defeitos epidérmicos de vários tipos, que podem ter origem em fatores bióticos ou fisiológicos (Azevedo et al., 2013; Pacheco e Duarte, 2016). A poda é uma prática cultural que pode surgir como estratégia para mitigar estes problemas e otimizar a produção de citrinos em vários outros aspetos (Matias et al., 2020). Esta, é uma operação que consiste, essencialmente, na remoção de órgãos vegetativos, modificando o desenvolvimento e a forma natural da árvore e afetando o seu comportamento fisiológico (Rodríguez e Villalba, 1998).
- Citrinos na Dieta Mediterrânica: frutos com sumo e com históriaPublication . Matias, Pedro; Duarte, Beatriz; Duarte, AmílcarOs citrinos são muito importantes para as populações mediterrânicas, do ponto de vista económico e social. A diversidade dos citrinos é encantadora, tal como a história da sua chegada à Europa. São originários da Ásia, mas existem no Mediterrâneo desde a Grécia Antiga. Atualmente, “tropeçamos” neles: plantamo-los nos nossos quintais, nas ruas das nossas cidades, em parques e jardins e produzimo-los em pomares com elevada qualidade. Usamos os seus frutos em muitos pratos que confecionamos e usufruímos dos seus enormes benefícios para a saúde.
- Recuperação de pomares de citrinos antigos através da podaPublication . Matias, Pedro; Mendonça, Angélica; Oliveira, Silvino; Duarte, AmilcarUma parte significativa da citricultura no Algarve é constituída por árvores antigas e de grande porte. Algumas destas árvores não são podadas há vários anos e apresentam grande porte e folhagem densa na periferia da copa. Isso dificulta a penetração da radiação solar e do ar no interior da copa, o que leva à morte dos ramos aí situados e ao desenvolvimento de uma “bola oca”.
- Effects of a severe recovery pruning in the productivity and fruit quality of two late orange cultivarsPublication . Matias, Pedro; Duarte, Beatriz; Mendonça, Angélica; Oliveira, Silvino; Barrote, Isabel; Guerrero, Carlos; Duarte, AmilcarCurrently, citrus production plays a major role in worldwide agriculture, especially in the Mediterranean. However, the typical irregular branch development and the formation of large canopies and dense exterior foliage can be significant limitations to light entry and air circulation through the canopy. Consequently, dead branches appear in the inner canopy, which becomes unproductive; flowering and vegetative growth occur only on the outer canopy, and the fruits formed usually are of lower quality. Furthermore, dead branches can be an inoculum for some pathogenic microorganisms, chemical treatments become less efficient since reaching the inner canopy branches becomes more difficult, and fruit harvest becomes harder and more expensive. Pruning is a cultural practice that allows canopy management and the control of the problems mentioned above. However, many citrus growers avoid or postpone pruning, or prune insufficiently due to pruning’s high costs and, sometimes, direct production losses. To assess the effects of pruning, two experiments were performed on large canopy trees: one in ‘Valencia Late’ and the other in ‘Dom João’. In both experiments, some trees were left unpruned (control) and others were severely pruned in November 2019 (recovery pruning). The pruning was made by removing at least 30% of the canopy, with the complete removal of a few large branches. Pruning allowed a significant increase in light availability inside the canopy. In the 2020 harvest, there were no differences in fruit size between treatments. The production decreased in the pruned trees in the ‘Dom João’ experiment, as expected, and was similar in the ‘Valencia Late’ experiment. In the 2021 harvest, in both experiments, the pruned trees had a smaller canopy, and the production was similar in both treatments. However, the fruits from pruned trees were bigger in the ‘Dom João’ experiment and several quality parameters were better in the ‘Valencia Late’ experiment.
- Effect of heading cuts on branch growth of ‘Encore’ mandarinPublication . Jacinto, Catarina; Matias, Pedro; Oliveira, Cristina; Duarte, AmilcarPruning can be used for various purposes in citriculture: to control the size and shape of the trees; improve fruit size and quality; manage the alternate bearing and control diseases and pests. However, the physiological response of the tree to heading cuts it´s not well documented. To supplement the lack of studies on the effect of pruning on branch growth, a trial was conducted on ’Encore’ mandarin, in the Algarve region, the main citrus-growing area of Portugal. Twenty-five sets of two branches that had completed growth and had similar characteristics in terms of vigor and position on the tree were selected. In July, one branch was left unpruned (control) and the other was pruned to half its length (pruned). New shoot growth (position in the branch, number, length, and type) was recorded from July to December. While control branches grew in the summer months and stopped in September, pruned branches grew more gradually and stopped in November. Pruned branches had a higher percentage of new growth (52%), compared to the control branches (25%). The pruning treatment also had a higher percentage of branches with new shoots (36%), compared to the control treatment (16%). In both treatments, the number of new shoots in the bud was higher at the branch tip and decreased towards the branch base. However, the pruned branches had more new shoots per bud at the tip of the branch than the control branches. There were no significant differences in total length of new shoots between control branches and pruned branches.
- Effect of fruit thinning on fruit quality and alternate bearing of ‘Setubalense’ mandarin (Citrus deliciosa)Publication . Guerreiro, T.; Trindade, Ana Rita; Duarte, Amilcar; Matias, PedroCitriculture plays a major role in agriculture worldwide, especially in the Mediterranean region. However, there are limitations in citrus production. Alternate bearing can be a big problem when it is very intense. Trees produce a heavy yield one year (“on” year) and light ones the next (“off” year). During the “on” year, trees produce many small-sized fruits, while in the “off” year, they produce very few, larger fruits. The small size of the fruits is a limitation, as they are less well accepted in the market. The ‘Setubalense’ cultivar, a traditional Portuguese Mediterranean mandarin (Citrus deliciosa), is recognized for its excellent organoleptic characteristics. Despite this, the issues of alternate bearing and small fruit size are leading to the loss of this cultivar. Fruit thinning is a cultural practice involving the removal of some fruits, while leaving others. This practice can be used to manage alternate bearing and to improve fruit size. However, its impact on the plant is not well understood, whether it affects the plant as a whole or at a more localized level, such as within individual branches. To address this, two experiments were installed in August 2019. In the first experiment thinning involved removing 50% of the fruits from the entire tree. In this experiment, the fruit size and fruit quality were higher in the trees where fruit thinning was performed. In the second experiment, thinning was applied to selected branches, also removing 50% of the fruits. In this case, no significant differences were observed, neither in fruit size nor in fruit quality. Furthermore, fruit thinning did not reduce alternate bearing in either experiment.
- Efficacy of slow sand filtration enriched with trichoderma atroviride in the control of rhizoctonia solani in soilless culturePublication . Matias, Pedro; Guerreiro David Coelho, Luísa Isabel; Reis, MárioSoilless cultivation is increasingly common, but the nutrient-rich drainage from substrate cultivation is often discarded. However, drainage can be safely reused if previously disinfected. Slow sand filtration (SSF) is a lowcost, ecological, and effective method for water disinfection, primarily through biological control. Enhancing SSF with antagonistic microorganisms is not well-studied. Additionally, SSF has not been tested to control Rhizoctonia solani, , a phytopathogen that can be spread by irrigation water. Therefore, the objective of his work was to test the efficacy of a slow sand filter improved through the inoculation of the antagonistic fungus Trichoderma atroviride, , evaluating its suppression capacity against Rhizoctonia solani spread by the irrigation water in a closed substrate cultivation of cucumber ( Cucumis sativus). ). Five experiments were conducted, testing the presence and absence of a sand filter, T. atroviride, , and R. solani in each trial. Median disease severity was expressed on a scale of 1-5. The improved SSF increased disease control percentage by 49% compared to SSF alone and by 86% compared to no disease control method. In some experiments, SSF with T. atroviride totally controlled R. solani. . The results confirm that biologically enhanced SSF with T. atroviride can effectively disinfect drainage in closed soilless cultivation systems infected with R. solani.