3 9 7 7 0 0 3 1 4 2 3 9 9 5 1 9 Allen, E. J. & Scott, R. K. (1992). Principles of agronomy and their application in the potato industry. In The Potato Crop. The scienti®c basis for improvement. (Second edn) (Ed.
P. M. Harris), pp. 816±881. London : Chapman & Hall.
Dixon, T. J. (1993). The role of micropropagation in the production of tubers for variety testing. Potato Research 36, 377±378.
(1991 a). Field performance of microtubers as propagation material. Potato Research 34, 353±364.
Haverkort, A. J., Uenk, D., Veroude, H. & Van de Waart, M. (1991 b). Relationships between ground cover, intercepted solar radiation, leaf area index and infrared re¯ectance of potato crops. Potato Research 34, 113±121.
Jeffries, R. A. & MacKerron, D. K. L. (1987). Aspects of the physiological basis of cultivar differences in yield of potato under droughted and irrigated conditions. Potato Research 30, 201±217.
Jones, E. D. (1988). A current assessment of in vitro culture and other rapid multiplication methods in North America and Europe. American Potato Journal 65, 209±220.
Kooman, P. L. & Haverkort, A. J. (1995). Modelling development and growth of the potato crop in¯uenced by temperature and daylength : LINTUL-POTATO. In Potato Ecology and Modelling of Crops Under Conditions Limiting Growth (Eds A. J. Haverkort & D. K. L.
MacKerron), pp. 41±60. Dordrecht : Kluwer Academic.
J. (1996 a). Effects of climate on different potato genotypes 1. Radiation interception, total and tuber dry matter production. European Journal of Agronomy 5, 193±205.