Characteristics of flowering stems and raceme position in macadamia

Wilkie, John; Sedgley, Margaret; Morris, Stephen; Muldoon, Steven J.; Olesen, Trevor

doi:10.1080/14620316.2009.11512537

Cited by 19 publications

(10 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2B) may be due to an increase in raceme number per BU. Additionally, negative correlations between the BU angle and node number and between the node number and racemes per BU (Table 2) suggested an interconnection with vigor; furthermore, it has been shown in macadamia that shorter shoots are more likely to flower (Wilkie et al, 2009). As with vegetative growth, more horizontal branch angles may improve the partitioning of assimilates to floral axillary buds (Zhang et al, 2017) due to reduced apical dominance in higher branch angles, which may partly explain these relationships.…”

Section: Discussionmentioning

confidence: 95%

“…Increased lateral (axillary) branching indirectly influenced canopy volume, possibly by allowing the vegetative parts of the canopy to spread in three dimensions, potentially increasing light interception but also possibly altering light distribution within the canopy due to increased shading. This trait is desirable in early growth to quickly fill orchard space and create a strong structure and in mature trees to generate new axillary positions for flower production (Wilkie et al, 2009). However, in mature trees, increased canopy volume from excessive branching is not desirable.…”

Section: Discussionmentioning

confidence: 99%

“…Similar branching traits are likely to be important for application to high-density macadamia orchards, although species-specific limitations may alter best practice. Because macadamia generally produces racemes in axillary positions (Wilkie et al, 2009), the need for branching may be less yield-limiting than it is in terminal flowering species. However, second-order lateral branching correlated significantly with raceme number per BU, raceme length, and raceme diameter ( Table 2), suggesting that increased branching (and, therefore, increased local light interception) may increase carbohydrates available for racemes and available axillary positions.…”

Section: Discussionmentioning

confidence: 99%

“…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).…”

mentioning

confidence: 99%

See 3 more Smart Citations

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

Toft¹,

Alam²,

Wilkie³

et al. 2019

horts

Self Cite

View full text Add to dashboard Cite

Additional index words. path analysis, plant architecture, planting density, intensification, vigor, productivity Abstract. The vigorous growth and large canopy size of commercial macadamia (Macadamia integrifolia, M. tetraphylla, and hybrids) cultivars generally restricts macadamia orchards to low-density planting. Little is known of the detailed interactions between plant architecture and yield components specific to macadamia. This chapter examines how dependent traits such as canopy size and yield might be determined by direct and indirect interactions between traits at different scales within the canopy. Fifteen genotypes (n = 3) were phenotyped in two growing seasons for architectural and reproductive traits, around the age of their transition from juvenility to maturity. Genotypes varied in canopy volume, cumulative yield, and canopy efficiency, and particular genotypes with low canopy volume and high yield were considered potentially useful for future high-density orchard systems. There was high variability in architectural, floral, and yield traits at multiple scales. Direct and indirect effects of architectural traits on the variability of yield and tree size were quantified using path coefficient analysis. Canopy volume was subject to positive direct effects from trunk cross-sectional area (TCA; 0.72), lateral branching (0.24), and branch unit (BU) length (0.24). Other traits showed significant indirect effects with canopy volume via TCA, such as branch cross-sectional area (BCA; 0.43), BU length (0.40), lateral branching (0.35), and internode length (0.32). Branch angle had a significant indirect negative effect on canopy volume via BU length (L0.11). Nut number had the strongest direct effect on yield (0.97), and this relationship was significantly indirectly influenced by raceme number (0.47), raceme length (0.50), nut number per raceme (0.33), canopy volume (0.37), and branch angle (0.35). In these relatively young trees, early yield was directly and positively influenced by canopy volume (0.12), presumably due to increased early light interception, which suggests that early canopy vigor contributes to early yield. This study suggests that yield and canopy size are determined by complex phenotypic interactions between architectural traits at different scales. Therefore, preplanting (i.e., scion and rootstock selections) and postplanting (i.e., pruning and training) manipulations that specifically manage architectural traits such as shoot length, branching, branch angle, raceme length, and nuts per raceme may result in the creation of efficient macadamia canopies.

show abstract

Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

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

Toft¹,

Alam²,

Wilkie³

et al. 2019

horts

Self Cite

View full text Add to dashboard Cite

show abstract

“…The finding that there was no difference in the number of stems emerging between trees exposed to the W-W temperature regime sequence and trees exposed to the C-C sequence is unexpected, given Wilkie et al's (2009) finding that stem emergence increases with temperature, and given the general positive relationship of plant vegetative growth and temperature. Possibly differences in branching occurred predominantly in the most distal growth units of the oldest axes (as seen in Chapter 3), and the pruning conducted here would have removed much of the difference between temperature treatments.…”

Section: Flowering and Branchingmentioning

confidence: 56%

Axillary bud behaviour in Macadamia integrifolia and its hybrids

Conway¹

View full text Add to dashboard Cite

Macadamia integrifolia and hybrids with M. tetraphylla are multiple flushing, subtropical trees which form the basis of the macadamia nut industry in Australia. However little is known about the process of inflorescence or new stem formation in these trees, including floral induction. Axillary buds form both new stems and inflorescences, so this thesis reports investigations into the effect of architectural position in the tree, and of temperature, on axillary bud release from dormancy and floral or vegetative identity.Location of inflorescence emergence and of new stem production over one year was mapped according to their locations within tree architecture. Bud location down to node level was related to proportion of nodes branching or flowering, and to number of inflorescences or stems per node. Nodes were mapped by position along the growth unit, by growth unit position along the axis, and node position along axes. Interactions of these positions with the size of axis and the size of growth units were also examined.Position of the node along the growth unit was the strongest factor influencing both proportion of nodes flowering and proportion of nodes branching. The proportion of nodes flowering increased with node proximity to the growth unit base. The proportion of nodes branching was highest by far on node two below the top of the growth unit.Pruning resulted in branching on the node or two immediately below the cut, whether the cut was at the top or base of a growth unit. However pruning did not increase numbers of new stems on the axis. Pruning did not change number or location of inflorescences on the growth unit pruned, but did increase inflorescences emerging from the growth unit below it, and significantly increased the number of inflorescences emerging from the axis by around 50%.Growth unit position along the axis also exerted a strong influence on location of inflorescences and new stems. Nodes on growth units closer to the base of an axis were more likely to flower than those on growth units towards the tip. Nodes of growth units closest to the tip were more likely to branch than those at the base.

show abstract