Seed potato quality as influenced by high temperatures during the growth period. 2. Sprouting pattern in several cultivars in response to storage temperature

Abstract

Locally grown seed tubers of nine varieties developing in spring or in autumn in a semi-arid region were examined for length of dormancy and for sprouting response. In spring, high temperatures during the last part of tuber development markedly shortened the dormant periods of tubers in comparison with tubers of the same varieties developing in autumn. The sprouting behaviour of tubers indicated that it is a varietal characteristic influenced by the change in environmental conditions during tuber development and storage. On tubers developing in spring and stored at high temperatures, three sprouting patterns were defined: a) apical dominance, characterized by the evident development of the apical sprout and less than 10% sprouting of the non-apical buds; b) apical influence, the apical sprout well developed and 10–20% sprouting of the non-apical buds; and c) simultaneous sprouting of 3 or 4 sprouts of similar size per tuber. It is suggested that apical dominance is a relative rather than an absolute phenomenon. The extent of dominance depends upon the variety's response to the high temperatures during tuber growth and storage.