THE VEGETATIVE DEVELOPMENT OF THE POTATO PLANT

A study of the vegetative growth of potato plants indicated that all varieties grown under identical conditions are likely to show similar growth rates during the early stages of development.
Differences in total leaf area per plant between varieties became apparent at the stage when rapid development of axillary shoots from the main axis occurred. The maincrop varieties, Stormont Dawn and King Edward, attained a greater total leaf area than the early varieties, Ulster Chieftain and Arran Pilot, because of the greater development of axillary shoots.
It is suggested that the number of nodes produced beneath the terminal inflorescence on the main axis approximates to a constant value, independent of variety. Varietal differences were manifested in the distribution between leaves above ground and stolons below, the early varieties producing fewer leaves above ground than the maincrop, in inverse proportion to the number of underground stolons.
The yields of tubers per plant are given for four varieties. Differences between varieties in the rate of tuber formation are related to differences in the development of haulms.
It is considered probable that the potato plant exhibits a basic growth form which is modified in each variety in a characteristic manner according to the stage in the growth cycle and the rate at which the growth substances are distributed to the various organs of the plant.