INTRODUCTION

Temperature pretreatment of excised floral parts is a technique used to improve response to anther culture in many species. In some solanaceous species including Solanum tuberosum (Uhrig 1983) pretreatment has involved placing the excised buds at low temperatures, usually around 6°C, for 2–7 days prior to culture. However, more recent investigations on Capsicum annuum (Dumas de Vaulx et al. 1981) have shown that for this species, high temperature pretreatment during the first days of culture (i.e. preincubation) gives optimum results. The first report of preincubation at high temperatures (30°C, 2 days) for a tuberous Solanum species was by Cappodocia et al. (1984) on S. chacoense and various hybrids. However, no comparison was made between this treatment and the cold pretreatment described above. The present study involved the dihaploid S. tuberosum H37O3 and compared the effects of various pretreatments before and during culture and included the use of both high and low temperatures in two experiments.

MATERIALS AND METHODS

Scions of S. tuberosum cv H37O3 were grafted onto tomato rootstocks to promote and prolong flowering. For the first experiment plants were grown in growth cabinets at 20°C day, 16°C night, 18h day. Illumination was provided by fluorescent tubes and 25W tungsten filament lamps (5000–8000 lux). For the second experiment the same procedure was adopted except that plants were glasshouse grown.