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Source–sink relations and effects of post-anthesis canopy defoliation in wheat at low latitudes

Published online by Cambridge University Press:  27 March 2009

P. K. Aggarwal
Affiliation:
Water Technology Centre, Indian Agricultural Research Institute, New Delhi 110012, India Multiple Cropping Department, International Rice Research Institute, PO Box 933, Manila, The Philippines
R. A. Fischer
Affiliation:
International Maize and Wheat Improvement Centre, Apdo. Postal 6-641, 06600 Mexico, DF, Mexico
S. P. Liboon
Affiliation:
Multiple Cropping Department, International Rice Research Institute, PO Box 933, Manila, The Philippines

Summary

Source–sink balance was studied by imposing different canopy defoliation treatments on wheat crops grown in Los Banos (Philippines) in 1985/86 and 1986/87, Sonora (Mexico) in 1972/73 and 1974/75 and New Delhi (India) in 1987/88. The crops were grown in replicated trials with optimum cultural management. Six defoliation treatments were imposed at anthesis on all shoots in the canopy in an area ranging between 1·65 and 3·0 m2. Defoliation reduced dry weight in proportion to the reduction in percentage light interception. The number of grains per unit land area was reduced slightly, and in most cases not significantly, except when all leaves were removed. Despite reduction of leaf lamina area index to as low as 0·5, the decrease in grain yield was small. In particular, flag leaf removal led to a remarkably small reduction in grain yield. Grain nitrogen content in defoliated crops decreased much less than expected from the amount of N removed by defoliation. The slope of the relation between reduction in grain yield with defoliation and reduction in post-anthesis dry matter accumulation was 0·56, indicating moderate source limitation for grain filling. The crops at the hottest site, in the Philippines, were less limited by source than the other crops. It is suggested that selection for smaller flag leaves may be worthwhile for high-input wheat crops.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1990

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References

REFERENCES

Aggarwal, P. K., Chaturvedi, G. S., Singh, A. K. & Sinha, S. K. (1986). Performance of wheat and triticale cultivars in a variable soil–water environment. III. Source–sink relationships. Field Crops Research 13, 317330.CrossRefGoogle Scholar
Bingham, J. (1969). The physiological determinants of grain yield in cereals. Agricultural Progress 44, 3041.Google Scholar
Evans, L. T., Wardlaw, I. F. & Fischer, R. A. (1975). Wheat. In Crop Physiology (Ed. Evans, L. T.), pp. 101149. New York: Cambridge University Press.Google Scholar
Fischer, R. A. (1973). The effect of water stress at various stages of development on yield processes in wheat. In Plant Responses to Climatic Factors (Ed. Slatyer, R. O.), pp. 230241. Paris: UNESCO.Google Scholar
Fischer, R. A. (1975). Yield potential of a dwarf spring wheat and the effect of shading. Crop Science 15, 607613.CrossRefGoogle Scholar
Fischer, R. A. (1985). Number of kernels in wheat crops and the influence of solar radiation and temperature. Journal of Agricultural Science, Cambridge 105, 447461.CrossRefGoogle Scholar
Fischer, R. A. & Kohn, G. D. (1966). The relationship of grain yield to vegetative growth and post flowering leaf area in the wheat crop under conditions of limited soil moisture. Australian Journal of Agricultural Research 17, 281295.CrossRefGoogle Scholar
Fischer, R. A. & Laing, D. R. (1976). Yield potential in a dwarf spring wheat and response to crop thinning. Journal of Agricultural Science, Cambridge 87, 113122.CrossRefGoogle Scholar
Fischer, R. A. & Stapper, M. (1987). Lodging effects on high yielding crops of irrigated semidwarf wheat. Field Crops Research 17, 245258.CrossRefGoogle Scholar
Gifford, R. M., Bremner, P. M. & Jones, D. B. (1973). Assessing photosynthetic limitation to grain yield in a field crop. Australian Journal of Agricultural Research 24, 297307.CrossRefGoogle Scholar
Puckridge, D. W. (1969). Photosynthesis of wheat under field conditions. II. Effect of defoliation on the carbon dioxide uptake of the community. Australian Journal of Agricultural Research 20, 623634.Google Scholar
Puckridge, D. W. (1971). Photosynthesis of wheat under field conditions. III. Seasonal trends in carbon dioxide uptake of crop communities. Australian Journal of Agricultural Research 22, 19.CrossRefGoogle Scholar
Spiertz, J. H. J.ten Hag, B. A. & Kupers, L. J. P. (1971). Relation between green area duration and grain yield in some spring varieties of spring wheat. Netherlands Journal of Agricultural Science 19, 211222.CrossRefGoogle Scholar
Stoy, V. (1965). Photosynthesis, respiration, and carbohydrate accumulation in spring wheat in relation to yield. Physiologia Plantarum Supplement IV, 125 pp.Google Scholar