The timing of pruning affects flushing, flowering and yield of macadamia

Abstract

Macadamia (Macadamia integrifolia, M. integrifolia  M. tetraphylla) trees were pruned at different times at sites near Alstonville, northern New South Wales, Australia, to examine the effects on vegetative flushing, subsequent flower raceme production and yield. Pruning of cv. 849 and cv. A268 modified the cycle of flush development. Pruning times that resulted in immature flushes on the canopy in late autumn or early winter inhibited raceme production. In contrast, pruning in late May and early June did not generally reduce raceme production relative to production on unpruned trees. The times of pruning that reduced raceme production also reduced yield. The yields of trees pruned in late May were also reduced, presumably because of decreased light interception. In the season after treatment the trees pruned in early April had greater numbers of racemes per unit of tree canopy volume than the trees pruned in late May. The trees of the lighter flowering cv. 849 pruned in early April had higher yield efficiencies than the trees pruned in late May, whereas there was no effect on yield efficiency in the prolifically flowering cv. A268. The differences in raceme production in the season after pruning may have been due to a combination of an alternate bearing response, characteristics of the stems produced after pruning, or maturity of the flushes. In a separate experiment, uniconazole sprays immediately after pruning reduced the length of the new stems, slowed canopy expansion, and increased kernel recovery compared with untreated hedged trees, but did not affect flowering or yield. In another experiment, hedging in early June had no effect on raceme production in cv. 849 trees in consecutive seasons, and no effect on canopy volume or yield in the first season. In contrast, canopy volume and yield were reduced in the second season. Finally, pruning of young, yet-to-flower cv. 849 trees from late winter to spring staggered flush development, with the earliest pruned trees producing more racemes and setting more fruit than the later pruned trees.

Pruning to control tree size, flowering and production of litchi

“…This was the first demonstration of such a response in a recurrent flushing tree species. The same effect has since been shown for avocado, Persea americana (Olesen, 2005), macadamia, Macadamia integrifolia (Olesen, 2005;Wilkie et al, 2010), and mango, Mangifera indica (Davenport, 2007;Wilkie et al, 2008b;Ramírez and Davenport, 2010). It is likely that this response will apply to other evergreen, recurrent flushing trees (Olesen, 2005;Wilkie et al, 2008a).…”

“…So the timing of hedging is important in order to maximise flowering and fruit production (Wilkie et al, 2010). For most of the subtropical species, pruning is aimed at producing new shoots during cool weather in winter when they are most likely to flower.…”

Phenotypic Association of Multi-scale Architectural Traits with Canopy Volume and Yield: Moving Toward High-density Systems for Macadamia

“…Current management techniques mainly rely on biomass removal using mechanical hedging, which is intended to maintain machinery access rather than canopy efficiency (McFadyen et al, 2011). Hedging may negatively affect yield by removing fruiting age wood Wilkie et al, 2009), stimulating competitive vegetative growth (Wilkie et al, 2010), and lowering the photosynthetic potential of newly exposed shade leaves (Huett, 2004). Selective limb removal has been shown to increase and to have no effect on or to decrease yield compared with unpruned trees (McFadyen et al, 2013;Olesen et al, 2011).…”

Initial Effects of Fertilization and Canopy Management on Flowering and Seed and Oil Yields of Jatropha curcas L. in Malawi

“…Pruning alters carbohydrate allocation from flowers and fruits to healing the wounds, response to pest, and disease and vegetative growth of new flush shoots [30,[38][39][40][41][42]. In Zambia, high J. curcas branch mortality and low resistance to pest and diseases were observed after pruning (own observation).…”