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. High-tillering 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/D(index) of internal plant competition accounted for most of the observed variation in maximum tiller number (N(tiller,max)) across genotypes. However, genotypic differences in the relationship between the S/D(index) and N(tiller,max) suggested that high-tillering hybrids also had a lower S/D threshold at which tillers appeared, possibly associated with hormonal effects. CONCLUSIONS: 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.
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. High-tillering 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/D(index) of internal plant competition accounted for most of the observed variation in maximum tiller number (N(tiller,max)) across genotypes. However, genotypic differences in the relationship between the S/D(index) and N(tiller,max) suggested that high-tillering hybrids also had a lower S/D threshold at which tillers appeared, possibly associated with hormonal effects. CONCLUSIONS: 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.
Authors: Dilbag S Multani; Steven P Briggs; Mark A Chamberlin; Joshua J Blakeslee; Angus S Murphy; Gurmukh S Johal Journal: Science Date: 2003-10-03 Impact factor: 47.728
Authors: Graeme Hammer; Mark Cooper; François Tardieu; Stephen Welch; Bruce Walsh; Fred van Eeuwijk; Scott Chapman; Dean Podlich Journal: Trends Plant Sci Date: 2006-11-07 Impact factor: 18.313
Authors: Karine Chenu; Scott C Chapman; Graeme L Hammer; Greg McLean; Halim Ben Haj Salah; François Tardieu Journal: Plant Cell Environ Date: 2007-12-10 Impact factor: 7.228
Authors: M M Alam; E S Mace; E J van Oosterom; A Cruickshank; C H Hunt; G L Hammer; D R Jordan Journal: Theor Appl Genet Date: 2014-08-28 Impact factor: 5.699
Authors: Vincent Vadez; Jana Kholová; Grégoire Hummel; Uladzimir Zhokhavets; S K Gupta; C Tom Hash Journal: J Exp Bot Date: 2015-06-01 Impact factor: 6.992
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Authors: M Fernanda Dreccer; Scott C Chapman; Allan R Rattey; Jodi Neal; Youhong Song; John Jack T Christopher; Matthew Reynolds Journal: J Exp Bot Date: 2012-12-03 Impact factor: 6.992