Regulation of tillering in sorghum: Genotypic effects

Kim, Hae Koo, Luquet, Delphine, van Oosterom, Erik, Dingkuhn, Michael and Hammer, Graeme (2010) Regulation of tillering in sorghum: Genotypic effects. Annals of Botany, 106 1: 69-78. doi:10.1093/aob/mcq080

Author Kim, Hae Koo
Luquet, Delphine
van Oosterom, Erik
Dingkuhn, Michael
Hammer, Graeme
Title Regulation of tillering in sorghum: Genotypic effects
Journal name Annals of Botany   Check publisher's open access policy
ISSN 0305-7364
Publication date 2010-07
Sub-type Article (original research)
DOI 10.1093/aob/mcq080
Volume 106
Issue 1
Start page 69
End page 78
Total pages 10
Place of publication Oxford, United Kingdom
Publisher Oxford University Press
Collection year 2011
Language eng
Formatted abstract
Background and Aims: Genotypic variation in tillering can be caused by differences in the carbon supply-demand balance within a plant. The aim of this study was to understand and quantify the effects of genotype on tillering as a consequence of the underlying internal competition for carbohydrates.

Methods: Five sorghum hybrids, derived from inbred lines with a common genetic background and with similar phenology and plant height but contrasting tillering, were grown in five experiments. The experiments covered a wide range in radiation and temperature conditions, so that number of tillers produced varied significantly. Data on leaf area, tiller number, and biomass accumulation and partitioning were collected at regular intervals. To quantify internal plant competition for carbohydrates, a carbohydrate supply-demand index (S/D index) was developed and related to variation in tillering.

Key Results:
The appearance of main shoot leaves and tillers was highly co-ordinated across genotypes. Hightillering hybrids had a greater appearance frequency of early tiller ranks than low-tillering hybrids, and this was associated with narrower and hence smaller main shoot leaves. A generalized S/Dindex of internal plant competition accounted for most of the observed variation in maximum tiller number (Ntiller,max) across genotypes. However, genotypic differences in the relationship between the S/Dindex and Ntiller,max suggested that high-tillering hybrids also had a lower S/D threshold at which tillers appeared, possibly associated with hormonal effects.

The results support the hypothesis that genotypic differences in tillering were associated with differences in plant carbon S/D balance, associated with differences in leaf size and in the threshold at which tillers grow out. The results provide avenues for phenotyping of mapping populations to identify genomic regions regulating tillering. Incorporating the results in crop growth simulation models could provide insight into the complex genotype-by-management-by-environment interactions associated with drought adaptation. © The Author 2010.
Keyword Carbohydrate supply-demand ratio
Genotype-by-environment interaction
Internal plant competition
Leaf area development
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2011 Collection
School of Agriculture and Food Sciences
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Citation counts: TR Web of Science Citation Count  Cited 14 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 17 times in Scopus Article | Citations
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Created: Sun, 11 Jul 2010, 00:09:41 EST