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- 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 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.