TREE SIZE CONTROL BY MEANS OF DEFICIT IRRIGATION IN 'ALGERIE' LOQUAT

Mechanically hedging the tops of macadamia trees to control tree size is referred to as topping. Topping the entire upper canopy causes a substantial reduction in yield and is not a recommended industry practice. Here we compare topping just half the upper canopy with full-topping, and with control trees that were not pruned, to test whether half-topping is a more acceptable means of size control, with less of a yield penalty. We used macadamia cultivar ‘A4’ as the subject for the study. The trees were topped horizontally at anthesis. Full-topping reduced yields by 78% in the first year and 63% in the second year compared with the control trees. By the end of the second year the height of the fully-topped trees was approximately the same as that of the control trees. In contrast, topping just the western half of the upper canopy resulted in little yield penalty. Yields were reduced non-significantly by 14% in the first year, and negligibly in the second year, compared with the control trees; and by the end of the second year, the regrowth on the topped halves of the trees was only two-thirds the height of that on the full-topped trees. The results are encouraging because topping is simple and cheap, and would be an attractive tree size control option for growers at the yield penalty described here for the half-topped treatment.

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Production Trends in Mature Macadamia Orchards and the Effects of Selective Limb Removal, Side-hedging, and Topping on Yield, Nut Characteristics, Tree Size, and Economics

HortTechnology ◽

10.21273/horttech.23.1.64 ◽

2013 ◽

Vol 23 (1) ◽

pp. 64-73 ◽

Cited By ~ 4

Author(s):

Lisa McFadyen ◽

David Robertson ◽

Margaret Sedgley ◽

Paul Kristiansen ◽

Trevor Olesen

Keyword(s):

Substantial Reduction ◽

Size Control ◽

Cost Effective ◽

Tree Size ◽

Macadamia Integrifolia ◽

Effective Removal ◽

Effect On Yield ◽

Yield Trends ◽

Disease Pressure

Yields of macadamia (Macadamia integrifolia, M. tetraphylla, and hybrids) orchards tend to increase with increasing tree size up to ≈94% light interception. Beyond this, there is some indication that crowding leads to yield decline, but the evidence is limited to one site. Increasing tree size and orchard crowding also present numerous management problems, including soil erosion, harvest delays, and increased pest and disease pressure. The aim of this study was to better characterize long-term yield trends in mature orchards and to assess the effects of manual and mechanical pruning strategies on yield, nut characteristics, tree size, and economics. We monitored yield at four sites in mature ‘344’ and ‘246’ orchards for up to seven years and confirmed a decline in yield with crowding for three of the sites. There was a small increase in yield over time at the fourth site, which may reflect the lower initial level of crowding and shorter monitoring period compared with the other sites, and highlights the need for long-term records to establish yield trends. Pruning to remove several large limbs from ‘246’ trees to improve light penetration into the canopy increased yield relative to control trees but the effect was short-lived and not cost-effective. Removal of a codominant leader from ‘344’ trees reduced yield by 21%. Annual side-hedging of ‘246’ trees reduced yield by 12% and mechanical topping of ‘344’ trees caused a substantial reduction in yield of up to 50%. Removal of limbs in the upper canopy to reduce the height of ‘344’ trees had less effect on yield than topping but re-pruning was not practical because of the extensive regrowth around the pruning cuts. Tree size control is necessary for efficient orchard management, but in this study, pruning strategies that controlled tree size also reduced yield. Research into the physiological response to pruning in macadamia is required to improve outcomes.

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Transformation of `Bosc' Pear (Pyrus communis L.) with the rolC Gene from Agrobacterium rhizogenes and Characterization of Transgenic Plants

HortScience ◽

10.21273/hortsci.33.3.461c ◽

1998 ◽

Vol 33 (3) ◽

pp. 461c-461

Author(s):

Ralph Scorza ◽

Richard L. Bell ◽

Chinnathambi Srinivasan ◽

Kevin Webb

Keyword(s):

Plant Growth ◽

Genetic Transformation ◽

Genetic Improvement ◽

Size Control ◽

The United States ◽

Tree Size ◽

Native Promoter ◽

Pyrus Communis L ◽

Size Controlling

Pear production in the United States relies on a few major cultivars, including `Bosc'. While there is a need for new cultivars, genetic improvement of the existing major cultivars through genetic transformation could have a major impact on the industry. We have developed a system for regeneration and transformation of pear. While the major objective of the transformation project is to improve resistance to fire blight (Erwinia amylovora) in major pear cultivars, tree size control is also one of the objectives in the genetic improvement of pear that may be approached through transformation. Traditionally, manipulation of tree size and vigor in established cultivars has been achieved through the use of size-controlling rootstocks. There are no completely satisfactory size-controlling rootstocks for pear. Genetic transformation provides an approach to developing new size-controlling rootstocks and also to directly affect the growth of the transgenic scion cultivar using genes that affect plant growth such as the rolC gene isolated from the bacterium A. rhizogenes, the causal agent of “hairy root” disease. This gene has been shown to alter growth and development in a number of plant species. To investigate the potential utility of the rolC gene in altering the growth of pear trees, `Bosc' pear was transformed with A. tumefaciens EHA101 carrying a pGA482-based plasmid containing the NPTII and GUS genes, and the rolC gene under the control of its native promoter. Four clones were isolated that were kanamycin-resistant and GUS-positive. PCR assays and DNA blots indicated the presence of the rolC gene in these clones. Each transgenic clone has been multiplied in vitro and planted in the greenhouse where transgene expression and plant growth are being evaluated.

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THE INFLUENCE OF TREE SIZE CONTROL AND PLANT DENSITY ON CITRUS PRODUCTIVITY

Acta Horticulturae ◽

10.17660/actahortic.1986.175.36 ◽

1986 ◽

pp. 249-254 ◽

Cited By ~ 3

Author(s):

R.J. Hutton

Keyword(s):

Plant Density ◽

Size Control ◽

Tree Size

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Interfacial studies in Nb3Sn superconductors

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100087264 ◽

1991 ◽

Vol 49 ◽

pp. 590-591

Author(s):

Ernest L. Hall ◽

Lee E. Rumaner ◽

Mark G. Benz

Keyword(s):

Grain Size ◽

Grain Boundaries ◽

Flux Pinning ◽

Size Control ◽

High Magnetic Fields ◽

Type Ii ◽

Reaction Interface ◽

Liquid Diffusion ◽

Type Ii Superconductor ◽

Grain Size Control

The intermetallic compound Nb3Sn is a type-II superconductor of interest because it has high values of critical current density Jc in high magnetic fields. One method of forming this compound involves diffusion of Sn into Nb foil containing small amounts of Zr and O. In order to maintain high values of Jc, it is important to keep the grain size in the Nb3Sn as small as possible, since the grain boundaries act as flux-pinning sites. It has been known for many years that Zr and O were essential to grain size control in this process. In previous work, we have shown that (a) the Sn is transported to the Nb3Sn/Nb interface by liquid diffusion along grain boundaries; (b) the Zr and O form small ZrO2 particles in the Nb3Sn grains; and (c) many very small Nb3Sn grains nucleate from a single Nb grain at the reaction interface. In this paper we report the results of detailed studies of the Nb3Sn/Nb3Sn, Nb3Sn/Nb, and Nb3Sn/ZrO2 interfaces.

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Size Control of Block Polymer Templated Mesoporous Silicate Materials

MRS Proceedings ◽

10.1557/proc-628-cc6.24 ◽

2000 ◽

Vol 628 ◽

Author(s):

Takeo Yamada ◽

Keisuke Asai ◽

Kenkichi Ishigure ◽

Akira Endo ◽

Hao S. Zhou ◽

...

Keyword(s):

Mesoporous Materials ◽

Molecular Sieve ◽

Mesoporous Material ◽

Triblock Copolymer ◽

Size Control ◽

Block Polymer ◽

New Class ◽

Mesoporous Silicate ◽

Cubic Structure ◽

Silicate Materials

ABSTRACTMesoporous materials have attracted considerable interest because of applications in molecular sieve, catalyst, and adsorbent. It will be useful for new functional device if functional molecules can be incorporated into the pore of mesoporous material. However, it is necessary to synthesize new mesoporous materials with controlled large pore size. Recently, new class of mesoporous materials has been prepared using triblock copolymer as a template. In this paper, we reported that hexagonal and cubic structure silicate mesoporous materials can be synthesized through triblock copolymer templating, and their size was controlled by synthesis condition at condensation.

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