Tuberization of aging potato tubers (Solanum tuberosum L.)

The onset of minituber from physiologically aged cultivar Russet Burbank potatoes may be a function of the decrease of available growth promoters such as gibberellic acid. Paclobutrazol, a synthetic chemical with properties of inhibition of gibberellic acid, was employed to study minituber induction in physiologically aged potatoes. The biochemical and agronomical value of physiologically aged potato tubers was examined over the next 4 chapters.; Chapter I explored sprout morphological changes and the biochemical status of potato tuber 'eye' tissue as monitored over 20 months of low temperature aging potatoes preceding and during minituber formation at 20°C. The significance of change in biochemistry and the possible relationship with growth regulating substances is discussed in regard to the delay or an enhancement of tuberization in aging potatoes.; Chapter II explored the influence of mist spray applications and timing of paclobutrazol had upon sprout and root development of various physiologically aged potatoes. Also examined was a possible relationship between sprouted potatoes receiving mist spray applications of paclobutrazol and an induced stress response as measured by ethylene and carbon dioxide evolution.; In Chapter III separate experiments were conducted to examine differences in growth responses between differing physiologically aged potatoes when treated with paclobutrazol alone or in combination with either gibberellic acid or kinetin. Performance difference between apical (bud) or basal (stem) ends to spray application to paclobutrazol alone, with kinetin or kinetin alone and a water control are discussed.; Chapter IV examined the effect of a daily verses intermittent spray application of paclobutrazol upon the number and fresh weight of individual minitubers produced from 'eyes' of treated apical and basal potato seed pieces. Whether there was a residual effect of paclobutrazol upon minituber vigor was assessed.