Phenotyping cotton ovule fibre initiation with spatial statistics
David Lovell A D , Yingru Wu B , Rosemary White C , Adriane Machado C , Danny J. Llewellyn C , Elizabeth S. Dennis C and Robert S. Anderssen AA CSIRO Mathematical and Information Sciences, GPO Box 664, Canberra, ACT 2601, Australia.
B Present address: Food Standards Australia New Zealand, PO Box 7186, Canberra, ACT 2610, Australia.
C CSIRO Plant Industry GPO Box 1600, Canberra, ACT 2601, Australia.
D Corresponding author. Email: David.Lovell@csiro.au
Australian Journal of Botany 55(6) 608-617 https://doi.org/10.1071/BT07003
Submitted: 9 January 2007 Accepted: 15 May 2007 Published: 27 September 2007
Abstract
Yield in cultivated cotton (Gossypium spp.) is affected by the number and distribution of fibres initiated on the seed surface but, apart from simple statistical summaries, little has been done to assess this phenotype quantitatively. Here we use two types of spatial statistics to describe and quantify differences in patterning of cotton ovule fibre initials (FI). The following five different species of Gossypium were analysed: G. hirsutum L., G. barbadense L., G. arboreum, G. raimondii Ulbrich. and G. trilobum (DC.) Skovsted. Scanning electron micrographs of FIs were taken on the day of anthesis. Cell centres for fibre and epidermal cells were digitised and analysed by spatial statistics methods appropriate for marked point processes and tessellations. Results were consistent with previously published reports of fibre number and spacing. However, it was shown that the spatial distributions of FIs in all of species examined exhibit regularity, and are not completely random as previously implied. The regular arrangement indicates FIs do not appear independently of each other and we surmise there may be some form of mutual inhibition specifying fibre-initial development. It is concluded that genetic control of FIs differs from that of stomata, another well studied plant idioblast. Since spatial statistics show clear species differences in the distribution of FIs within this genus, they provide a useful method for phenotyping cotton.
Acknowledgements
We thank Union Huynh for digitising the images and Merran Hunter and Todd Collins for caring for the cotton plants grown in the glasshouse. Celia Miller produced the SEM images used for the analysis. We thank the NSW Centre for Agricultural Genomics, the Cotton Research and Development Corporation and Cotton Seed Distributors for partial funding of this research. We gratefully acknowledge the insights that Adrian Baddeley provided in his reviews of drafts of this paper, as well as the comments of two anonymous reviewers.
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To enable the statistical analyses described in this paper to be reproduced, we provide BT07003_AC.zip which contains the following 19 data sets in electronic form to be made available on request to the Australian Journal of Botany:
Gossypium arboreum1.ppp
Gossypium arboreum3.ppp
Gossypium arboreum4.ppp
Gossypium arboreum5.ppp
Gossypium barbadense1.ppp
Gossypium barbadense2.ppp
Gossypium barbadense3.ppp
Gossypium barbadense5.ppp
Gossypium hirsutum1.ppp
Gossypium hirsutum2.ppp
Gossypium hirsutum3.ppp
Gossypium hirsutum5.ppp
Gossypium hirsutum6.ppp
Gossypium raimondii1.ppp
Gossypium raimondii2.ppp
Gossypium raimondii3.ppp
Gossypium trilobum1.ppp
Gossypium trilobum2.ppp
Gossypium trilobum3.ppp
Each of these files contains information about the cell centres observed in the images analysed in the present paper. The file name describes the species and image number. Within each file, each line contains
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the x-coordinate of a cell centre in μm,
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the y-coordinate of a cell centre in μm and
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the cell type (‘trichome’ or ‘non-trichome’).
