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Roger R B Leakey - One of the best experts on this subject based on the ideXlab platform.
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the ideotype concept and its application to the Selection of aftp cultivars this chapter was previously published in leakey r r b page t 2006 forests trees and livelihoods 16 5 16
Multifunctional Agriculture#R##N#Achieiving Sustainable Development in Africa, 2017Co-Authors: Roger R B LeakeyAbstract:The ideotype concept has been developed and modified for a number of different crops, including forest trees, over the last 35 years. In recent years it has been used in the domestication of agroforestry trees producing Agroforestry Tree Products (AFTPs), as an aid to the Multiple-Trait Selection of superior trees for cultivar development. For example in west and central Africa, “fruit” and “kernel” ideotypes have been identified in Irvingia gabonensis (Bush Mango), based on quantitative characterisation of a number of fruit, nut and kernel Traits. Subsequently, recognising the opportunity to develop different markets for the commercially important kernels, the “kernel ideotype” has been subdivided into “oil” and “food-thickening” ideotypes, with options for further subdivision of the latter into ideotypes with either high viscosity or high drawability characteristics. Similar opportunities for the development of single-purpose cultivars from multi-purpose species have been identified in Sclerocarya birrea (Marula), indicating that with increasing information about the variability of AFTP’s it is possible to develop a hierarchy of different ideotypes to meet different market opportunities. In Sc. birrea and Dacryodes edulis , future options exist to extend ideotypes with recognition of the variability in both nutritional and organoleptic qualities. In Australia, a very broad-based ideotype has been developed for the indigenous shrub Kunzea pomifera (Muntries) established on both morphological and physiological Traits. Similar approaches are identified for timber trees (e.g. Triplochiton scleroxylon ) and those like Santalum austrocaledonicum producing essential oils. It is concluded that ideotypes are a useful tool for visualising and conceptualising how to combine specific rare combinations of visible and invisible Traits, aimed at the maximisation of Harvest Index, even when the Traits are only weakly related.
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chapter 24 domestication potential of marula sclerocarya birrea subsp caffra in south africa and namibia 3 Multiple Trait Selection this chapter was previously published in leakey r r b 2005 agroforestry systems 64 51 59 with permission of springer
Multifunctional Agriculture#R##N#Achieiving Sustainable Development in Africa, 2017Co-Authors: Roger R B LeakeyAbstract:An understanding of the inter-relationships between the Traits characterising tree-to-tree variation in fruits and kernels is fundamental to the development of selected cultivars based on Multiple Trait Selection. Using data from previously characterised marula ( Sclerocarya birrea ) trees in Bushbuckridge, South Africa and North Central Region of Namibia, this study examines the relationships between the different Traits (fruit pulp, flesh/juice mass, and nut shell and kernel mass) as a means to determine the opportunities to develop cultivars. Strong and highly significant relationships were found between fruit mass and pulp mass in trees from South Africa and Namibia, indicating that size is a good predictor of fruit pulp production. However, fruit size is not a good predictor of nut or kernel production, as there were weak relationships between fruit and nut and/or kernel mass, which varied between sites and landuses. Generally, the relationships between fruit mass and kernel mass were weaker than between fruit mass and nut mass. Relationships between kernel mass and shell mass were generally weak. The lack of strong relationships between fruit and kernel mass does, however, imply that there are opportunities to identify trees with either big fruits/small nuts for pulp production, or trees with large kernels in relatively small fruits for kernel oil production. However, within fruits from the same tree, nuts could contain 0 – 4 kernels, indicating that even in trees with an inherent propensity for large kernels, improved pollination may be required to maximise kernel mass through an increase in kernel number. Finally, the relationships between percentage kernel oil content and the measured morphological Traits were also very weak. The conclusions of these results are that there is merit in identifying different combinations of Traits for the Selection of trees producing either pulp or kernels. Consequently, fruit and kernel “ideotypes” are presented as guides to the Selection of elite trees for cultivar development. These results have important implications for the domestication of the species as a producer of fruits or kernels for food/beverages or cosmetic oils.
Junji Matsumura - One of the best experts on this subject based on the ideXlab platform.
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Multiple Trait Selection index for simultaneous improvement of wood properties and growth Traits in pinus kesiya royle ex gordon in malawi
Forests, 2017Co-Authors: Edward Missanjo, Junji MatsumuraAbstract:Tree breeders face the problem of negative correlations between wood properties and growth Traits. It is necessary to overcome this difficulty in order to obtain promising genotypes. The Selection index is one of the helpful tools in this process, because it allows Multiple features of interest to be selected. In this study, a Multiple Trait Selection index for Khasi pine (Pinus kesiya Royle ex Gordon) grown in Malawi was developed. Data on wood properties and growth Traits were collected from six families of P. kesiya at the age of 30 years. The breeding objective was defined in terms of wood stiffness, wood strength and volume. Selection Traits included in the index were wood stiffness (MoE), wood strength (MoR), volume (Vol.), wood density (WD), and diameter at breast height (DBH). The index was termed as I T = − 80.36 M o E − 14.60 M o R + 132.07 V o l . + 4858.09 W D − 7.56 D B H . The accuracy of the index was 98.8% and the correlation between the index and the aggregate breeding objective was 0.994. A genetic gain of 16.7% for volume, 14.8% for wood stiffness and 13.2% for wood strength would be expected from a standardized 10% Selection intensity. Therefore, application of the developed Selection index is necessary in order to increase the efficiency of the Pinus kesiya breeding programme in Malawi.
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genetic improvement of wood properties in pinus kesiya royle ex gordon for sawn timber production in malawi
Forests, 2016Co-Authors: Edward Missanjo, Junji MatsumuraAbstract:Accurate prediction of genetic potential and response to Selection in breeding requires knowledge of genetic parameters for important Selection Traits. In this study, we estimated genetic parameters for wood properties in Khasi pine (Pinus kesiya Royle ex Gordon) grown in Malawi. Data on wood properties and growth Traits were collected from six families of Pinus kesiya at the age of 30. The results show that wood density had a higher genetic control (h2 = 0.595 ± 0.055) than wood stiffness (h2 = 0.559 ± 0.038) and wood strength (h2 = 0.542 ± 0.091). The genetic correlation among wood quality Traits was significantly moderate (0.464 ± 0.061) to high (0.735 ± 0.025). The predicted genetic response indicated that Selection for wood density at 10% Selection intensity would increase stiffness and strength by 12.6% and 8.85%, respectively. The genetic correlations between growth and wood quality Traits were moderately unfavourable. However, sufficient variation exists within the breeding population to select individuals with both good growth rate and high wood quality Traits. It is therefore suggested that all trees with both diameter at breast height (DBH) greater than 32.0 cm and density greater than 0.593 g/cm3 must be selected in order to increase the efficiency of the breeding programme. However, in the long term, it is recommended that the best Selection strategy would be to develop a Multiple-Trait Selection index. The Selection index should be developed using optimal index weights for the advanced Pinus kesiya breeding programme in Malawi.
S A Barwick - One of the best experts on this subject based on the ideXlab platform.
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methods and consequences of including reduction in greenhouse gas emission in beef cattle Multiple Trait Selection
Genetics Selection Evolution, 2019Co-Authors: S A Barwick, Anthony L Henzell, R M Herd, B J Walmsley, Paul F ArthurAbstract:Societal pressures exist to reduce greenhouse gas (GHG) emissions from farm animals, especially in beef cattle. Both total GHG and GHG emissions per unit of product decrease as productivity increases. Limitations of previous studies on GHG emissions are that they generally describe feed intake inadequately, assess the consequences of Selection on particular Traits only, or examine consequences for only part of the production chain. Here, we examine GHG emissions for the whole production chain, with the estimated cost of carbon included as an extra cost on Traits in the breeding objective of the production system. We examined an example beef production system where economic merit was measured from weaning to slaughter. The estimated cost of the carbon dioxide equivalent (CO2-e) associated with feed intake change is included in the economic values calculated for the breeding objective Traits and comes in addition to the cost of the feed associated with Trait change. GHG emission effects on the production system are accumulated over the breeding objective Traits, and the reduction in GHG emissions is evaluated, for different carbon prices, both for the individual animal and the production system. Multiple-Trait Selection in beef cattle can reduce total GHG and GHG emissions per unit of product while increasing economic performance if the cost of feed in the breeding objective is high. When carbon price was $10, $20, $30 and $40/ton CO2-e, Selection decreased total GHG emissions by 1.1, 1.6, 2.1 and 2.6% per generation, respectively. When the cost of feed for the breeding objective was low, Selection reduced total GHG emissions only if carbon price was high (~ $80/ton CO2-e). Ignoring the costs of GHG emissions when feed cost was low substantially increased emissions (e.g. 4.4% per generation or ~ 8.8% in 10 years). The ability to reduce GHG emissions in beef cattle depends on the cost of feed in the breeding objective of the production system. Multiple-Trait Selection will reduce emissions, while improving economic performance, if the cost of feed in the breeding objective is high. If it is low, greater growth will be favoured, leading to an increase in GHG emissions that may be undesirable.
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methods and consequences of including feed intake and efficiency in genetic Selection for Multiple Trait merit
Journal of Animal Science, 2018Co-Authors: S A Barwick, Anthony L Henzell, B J Walmsley, D J Johnston, R G BanksAbstract:Methods are presented for including feed intake and efficiency in genetic Selection for Multiple-Trait merit when commercial production is from any combination of pasture or concentrates. Consequences for the production system and for individual animals are illustrated with a beef cattle example. Residual feed intake at pasture (RFI-p), residual feed intake in the feedlot (RFI-f), and cow condition score are additional Traits of the breeding objective. Feed requirement change is costed in the economic values of other objective Traits. Selection responses are examined when feed costs are ignored, partially or fully included in the breeding objective, and when net feed intake (NFI) EBVs are added to the index. When all feed cost was included and NFI EBVs were in the index, Selection (with Selection intensity, i = 1) increased production system $ net return by 6.0%, $ per unit of product by 5.2%, $ per unit of feed by 6.6%, total product by 0.7% and product per unit of feed by 1.3%. There was little change in production system total feed. When feed cost was ignored, Selection decreased production system $ net return, $ per unit of product, and $ per unit of feed. At the individual Trait level, when feed was fully included there were increases in weaning weight-direct (0.8 kg), feedlot entry weight (1.4 kg), dressing % (0.04%), carcass meat % (0.36%), carcase fat depth (0.12 mm), carcass marbling score (0.02 score), cow condition score (0.01 score), calving ease-direct (0.97%), calving ease-maternal (0.22%) and cow weaning rate (1.3%), and decreases in weaning weight-maternal (-0.9 kg), RFI-p (-0.09 kg DM/d), RFI-f (-0.11 kg DM/d), sale weight (-1.6 kg) and cow weight (-8.7 kg). Gains were evident over a range of feed price. Selection for $ net return also increased $ net return per unit of feed, suggesting that $ net return per unit area would increase in grazing industries. Feed cost for Trait change was the source of a major genotype × environment interaction affecting animal rankings. Where industry production environments vary, and feed cost for Trait change varies with the environment, we recommend that industry indexes be derived for more than one level of feed cost. Cow condition score did not decline while biological and economic efficiency of the production system and individual animal were improving, suggesting that efficiency can be improved under Multiple-Trait Selection without compromising breeding cow welfare.
Paul F Arthur - One of the best experts on this subject based on the ideXlab platform.
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methods and consequences of including reduction in greenhouse gas emission in beef cattle Multiple Trait Selection
Genetics Selection Evolution, 2019Co-Authors: S A Barwick, Anthony L Henzell, R M Herd, B J Walmsley, Paul F ArthurAbstract:Societal pressures exist to reduce greenhouse gas (GHG) emissions from farm animals, especially in beef cattle. Both total GHG and GHG emissions per unit of product decrease as productivity increases. Limitations of previous studies on GHG emissions are that they generally describe feed intake inadequately, assess the consequences of Selection on particular Traits only, or examine consequences for only part of the production chain. Here, we examine GHG emissions for the whole production chain, with the estimated cost of carbon included as an extra cost on Traits in the breeding objective of the production system. We examined an example beef production system where economic merit was measured from weaning to slaughter. The estimated cost of the carbon dioxide equivalent (CO2-e) associated with feed intake change is included in the economic values calculated for the breeding objective Traits and comes in addition to the cost of the feed associated with Trait change. GHG emission effects on the production system are accumulated over the breeding objective Traits, and the reduction in GHG emissions is evaluated, for different carbon prices, both for the individual animal and the production system. Multiple-Trait Selection in beef cattle can reduce total GHG and GHG emissions per unit of product while increasing economic performance if the cost of feed in the breeding objective is high. When carbon price was $10, $20, $30 and $40/ton CO2-e, Selection decreased total GHG emissions by 1.1, 1.6, 2.1 and 2.6% per generation, respectively. When the cost of feed for the breeding objective was low, Selection reduced total GHG emissions only if carbon price was high (~ $80/ton CO2-e). Ignoring the costs of GHG emissions when feed cost was low substantially increased emissions (e.g. 4.4% per generation or ~ 8.8% in 10 years). The ability to reduce GHG emissions in beef cattle depends on the cost of feed in the breeding objective of the production system. Multiple-Trait Selection will reduce emissions, while improving economic performance, if the cost of feed in the breeding objective is high. If it is low, greater growth will be favoured, leading to an increase in GHG emissions that may be undesirable.
Mathew Koshy - One of the best experts on this subject based on the ideXlab platform.
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Optimization of Multiple Trait Selection in western hemlock (Tsuga heterophylla (Raf.) Sarg.) including pulp and paper properties
Annals of Forest Science, 2002Co-Authors: Milosh Ivkovich, Mathew KoshyAbstract:Options for incorporating wood quality in British Columbia's hemlock breeding program were investigated. Seventy half-sib families were examined. Attention was given to quantitative variation in tracheid characteristics and its effects on pulp and paper properties. Based on the existing knowledge of relationships between fibre properties and paper quality, the potential gain in yield and wood quality was estimated for different Selection strategies. Improvement without much trade-off was possible for volume and tensile strength of pulp and paper. Significant trade-offs would be required to improve the volume, tear strength of paper and strength of mechanical pulp. Therefore, multiobjective optimization would be beneficial. Conservative Selection strategies seem realistic, and compromises with gain in volume growth may be profitable. The potential loss arising from the uncertainty about economic values for objectives can be overcome by using different Selection indices in Multiple breeding populations.
