Abstract
A method developed to assess family competition effects (partner effects) in variety trials was applied to the cocoa tree. The study was conducted in a hybrid trial, involving twelve families of 50 trees each planted in a totally randomised single-tree plot design, at a density of 1,667 trees ha-1. The trial was thinned 10 years after planting, at a rate of two out of four rows. Competition was studied with reference to juvenile and adult vegetative vigour, to periodic and cumulative yields (number of pods, potential total pod weight and average weight of one pod), and the yield x vigour ratio or "cropping efficiency" (total pod weight divided by the trunk cross-section). At the end of the trial, after thirteen years of monitoring, competition effects were revealed which explained 8 to 10% of the residual variance after removal of the hybrid and micro-environmental effects. The competition effects, which were detectable by 18 months after planting for vigour, occurred earlier than generally acknowledged. Competition effects for yield increased with age of the plantation and decreased drastically after thinning at 10 years. Under the trial conditions, the families could be classified as "aggressive", "stimulating" or "passive" in relation to their neighbours. Vegetative vigour (trunk cross-sectional area) explained up to 34% of the competition effects affecting vegetative development- total pod production and total pod weight over the period concerned. The partner effects on the production variables could never be explained by any of the production variables themselves, hence it should be possible to select non-aggressive high-yielding families. No significant partner effect was observed for average pod weight. The improvement of the cropping efficiency, and more generally management of vegetative vigour, can follow genetic and plant husbandry pathways and these are considered in the Discussion. The genetic pathway entails the selection of hybrid or clonal material with low vigour and/or the search for dwarfing rootstocks. The plant husbandry pathway involves developing designs and techniques (such as thinning, pruning, etc...), which might decrease the competition effects between trees in a given plot situation.
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Claims 11
Claim · model-written summary
Competition (partner) effects explained 8 to 10% of the residual variance in cocoa after removal of hybrid and micro-environmental effects.
- Taxon
- cocoa tree
Theobroma cacaoe0 - Treatment
- competition effectse1
- Outcome
- residual variancee1
- Value
- 8 to 10%e1
- Qualifier
- after removal of the hybrid and micro-environmental effectse1
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“applied to the cocoa tree”
e1“competition effects were revealed which explained 8 to 10% of the residual variance after removal of the hybrid and micro-environmental effects”
Claim · model-written summary
Competition effects on cocoa vigour were detectable by 18 months after planting, earlier than generally acknowledged.
- Taxon
- cocoa treeTheobroma cacaoe0
- Outcome
- vigoure2
- Value
- 18 months after plantinge2
- Qualifier
- occurred earlier than generally acknowledgede2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“applied to the cocoa tree”
e2“The competition effects, which were detectable by 18 months after planting for vigour, occurred earlier than generally acknowledged”
Claim · model-written summary
Competition effects for cocoa yield increased with the age of the plantation.
- Taxon
- cocoa treeTheobroma cacaoe0
- Treatment
- age of the plantatione3
- Outcome
- Competition effects for yielde3
- Direction
- increasede3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“applied to the cocoa tree”
e3“Competition effects for yield increased with age of the plantation and decreased drastically after thinning at 10 years”
Claim · model-written summary
Competition effects for cocoa yield decreased drastically after thinning at 10 years.
- Taxon
- cocoa treeTheobroma cacaoe0
- Treatment
- thinning at 10 yearse3
- Outcome
- Competition effects for yielde3
- Direction
- decreased drasticallye3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“applied to the cocoa tree”
e3“Competition effects for yield increased with age of the plantation and decreased drastically after thinning at 10 years”
Claim · model-written summary
Under the trial conditions the cocoa families could be classified as aggressive, stimulating or passive relative to their neighbours.
- Taxon
- cocoa treeTheobroma cacaoe0
- Outcome
- families could be classifiede4
- Qualifier
- in relation to their neighbourse4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“applied to the cocoa tree”
e4“the families could be classified as "aggressive", "stimulating" or "passive" in relation to their neighbours”
Claim · model-written summary
Vegetative vigour (trunk cross-sectional area) explained up to 34% of the competition effects affecting vegetative development, total pod production and total pod weight, in cocoa.
- Taxon
- cocoa treeTheobroma cacaoe0
- Treatment
- Vegetative vigour (trunk cross-sectional area)e5
- Outcome
- competition effects affecting vegetative developmente5
- Value
- up to 34%e5
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“applied to the cocoa tree”
e5“Vegetative vigour (trunk cross-sectional area) explained up to 34% of the competition effects affecting vegetative development- total pod production and total pod weight”
Claim · model-written summary
Partner effects on the production variables of cocoa could not be explained by the production variables themselves.
- Taxon
- cocoa treeTheobroma cacaoe0
- Outcome
- partner effects on the production variablese6
- Comparator
- any of the production variables themselvese6
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“applied to the cocoa tree”
e6“The partner effects on the production variables could never be explained by any of the production variables themselves, hence it should be possible to select non-aggressive high-yielding families”
Claim · model-written summary
No significant partner effect was observed for cocoa average pod weight.
- Taxon
- cocoa treeTheobroma cacaoe0
- Outcome
- average pod weighte7
- Qualifier
- No significant partner effecte7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“applied to the cocoa tree”
e7“No significant partner effect was observed for average pod weight”
Claim · model-written summary
It should be possible to select non-aggressive high-yielding cocoa families.
- Taxon
- cocoa treeTheobroma cacaoe0
- Outcome
- select non-aggressive high-yielding familiese6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“applied to the cocoa tree”
e6“The partner effects on the production variables could never be explained by any of the production variables themselves, hence it should be possible to select non-aggressive high-yielding families”
Claim · model-written summary
Improvement of cropping efficiency in cocoa can follow genetic and plant husbandry pathways, including management of vegetative vigour.
- Taxon
- cocoa treeTheobroma cacaoe0
- Outcome
- improvement of the cropping efficiencye1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“applied to the cocoa tree”
e1“The improvement of the cropping efficiency, and more generally management of vegetative vigour, can follow genetic and plant husbandry pathways”
Claim · model-written summary
The genetic pathway for cocoa is selection of hybrid or clonal material with low vigour.
- Taxon
- cocoa treeTheobroma cacaoe0
- Outcome
- selection of hybrid or clonal material with low vigoure2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“applied to the cocoa tree”
e2“The genetic pathway entails the selection of hybrid or clonal material with low vigour”