Modelling Environmental and Genetic Control of Tillering in Sorghum

Hae Koo Kim (2008). Modelling Environmental and Genetic Control of Tillering in Sorghum PhD Thesis, School of Land, Crop and Food Sciences, The University of Queensland.

       
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Author Hae Koo Kim
Thesis Title Modelling Environmental and Genetic Control of Tillering in Sorghum
School, Centre or Institute School of Land, Crop and Food Sciences
Institution The University of Queensland
Publication date 2008-05-01
Thesis type PhD Thesis
Supervisor Graeme Hammer
Erik van Oosterom
Delphine Luquet
Michael Dingkuhn
Total pages 200
Total colour pages 7
Total black and white pages 193
Subjects 300000 Agricultural, Veterinary and Environmental Sciences
Formatted abstract
This thesis develops a conceptual modelling framework formalizing the environmental (E)
and genetic (G) components of tillering control by carbohydrate (C) assimilate availability in
sorghum (supply/demand ratio, S/D). This concept was elaborated and tested across five
experiments and six contrasting genotypes in terms of tillering ability. The results showed that
regulation of tillering was strongly related to its competition with main stem development and
leaf morphogenesis, by influencing the appearance frequency of the lower-rank tillers. An
indicator of internal competition for C, S/Dindex, was developed and allowed to explain
tillering response across the range of G and E investigated. Once confirmed by analysis of
sugar distribution within the plant, this indicator was applied (i) to support a genetic study,
which identified three quantitative trait loci (QTLs) associated with tillering ability, two of
which could be specifically associated with genetic components of S/Dindex (related to leaf
width and a S/D threshold for tillering); and (ii) to improve and evaluate an existing plant
model (EcoMeristem). Results of this study open new opportunities to investigate the
following: (i) G and E bases of the relationship between C dynamics and tillering ability, (ii)
the stability of model-based QTLs and (iii) further improvement of EcoMeristem and other
models such as APSIM to connect them to genetic information and help develop new
sorghum ideotypes.
KEYWORDS: Sorghum bicolor (L.) Moench, internal competition for carbohydrate, supplydemand
ratio, ecophysiological trait dissection, leaf area development, tiller hierarchy, leaf
width, tillering threshold, modelling framework, QTL
Additional Notes Page numbers in color (pdf file page number): 1, 103, 106, 108-109, 123, 135

 
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Created: Thu, 16 Oct 2008, 07:22:26 EST by Mr Hae Koo Kim