In the past decade there have been several books and reviews which have considered the physiology of potatoes (Ivins and Mil thorpe, 1963;Burton, 1966;Milthorpe and Moorby, 1967;Moorby and Milthorpe, 1975). The first two of these were concerned, in part, with trying to put the study of the potato crop on a firm fundamental basis. The second two reviews reported how this work was proceeding. It seems appropriate for the purposes of this book to describe the present state of our knowledge of potato physiology and, probably more important, to discuss how our attitudes and research priorities have changed and suggest areas where we appear to need further information.Discussions such as this have usually started with the dormant tuber and subsequent development of sprouts during storage. I believe that basic physiology of sprout growth is now well understood and I intend to devote more attention to non-storage growth. The first, and major part of the chapter will be concerned, therefore, with growth in the field and the development of the crop of tubers. Physiological aspects of storage will then be considered and sprout growth discussed in terms of its management for different purposes.
Growth in the field
Pre-emergence growthThe potato is different from most other major annual crops in that it is usually propagated vegetatively. The seed tuber bears a number of sprouts, some or all of which may be growing. It is these growing sprouts which produce the daughter plant and the subsequent crop and, unless P. M. Harris (ed.), The Potato Crop