ABSTRACT

The present study evaluated the effect of pruning according to different tree forms on yield, fruit size, and leaf starch reserves of young ‘Nadorcott’ mandarin trees planted at high density. Trees were selectively pruned by hand either according to form (pyramid or open center) by removing either lateral or central branches, or were left unpruned until trees touched each other in the row with minimal pruning thereafter (control). Form pruning, in particular the pyramid form, resulted in higher amount of biomass removal compared with the control treatment, affecting canopy volume and trunk cross-sectional area (TCSA). This led to a yield reduction in the first year, but steady yield increases in subsequent years. Fruit size was significantly larger in pyramid and open-center-shaped trees compared with the control treatment, but this difference declined as trees got older. Production efficiency (yield/canopy volume) of the pyramid form was significantly higher after the second year of pruning compared with the other treatments. Pruning did not influence leaf starch content, but indirectly affected crop load and subsequently the following year’s crop size. Judicial removal of lateral branches, e.g. in pyramid-shaped trees, appeared to be the most beneficial tree form for ‘Nadorcott’ mandarin as it is closest to its natural growth habit and promotes sustainable yields with good marketable fruit size.

摘要

本研究评估了根据不同树形进行修剪对高密度种植的年轻“Nadorcott”柑橘树的产量、果实大小和叶片淀粉储备的影响。根据形状（金字塔形或开放中心），通过去除侧枝或中央枝条，选择性地手工修剪树木，或者不修剪树木，直到树木在行中相互接触，然后进行最小修剪（对照）。与对照处理相比，形状修剪，特别是金字塔形状，导致更高的生物量去除量，影响树冠体积和树干横截面积 (TC​​SA)。这导致第一年产量下降，但随后几年产量稳定增加。与对照处理相比，金字塔形和开心形树的果实大小显着更大，但随着树木变老，这种差异逐渐减小。与其他处理相比，修剪第二年后金字塔形的生产效率（产量/冠层体积）显着更高。修剪不影响叶片淀粉含量，但间接影响作物负荷和随后一年的作物大小。司法去除侧枝，例如在金字塔形树中，似乎是对“Nadorcott”柑橘最有益的树形，因为它最接近其自然生长习性，并促进可持续的产量和良好的适销果实大小。但间接影响了作物负荷并随后影响了下一年的作物规模。司法去除侧枝，例如在金字塔形树中，似乎是对“Nadorcott”柑橘最有益的树形，因为它最接近其自然生长习性，并促进可持续的产量和良好的适销果实大小。但间接影响了作物负荷并随后影响了下一年的作物规模。司法去除侧枝，例如在金字塔形树中，似乎是对“Nadorcott”柑橘最有益的树形，因为它最接近其自然生长习性，并促进可持续的产量和良好的适销果实大小。