Effetto delle condizioni di coltura e della somma termica sullo stato di dormienza del tubero seme di nuovi cloni italiani

Introduction. Potato tuber dormancy length is affected by genetic, hormonal and environmental factors, so that it is difficult to define tuber physiological age. Histological and physiological similarity among microtubers and tubers allows to utilize in vitro technique in studying the answer of different potato genotypes in relation to variable factors, such as photoperiod, cultivation environment, tuber conservation temperature.. Materials and methods. The research activity has been subdivided into two trials: in vitro and in vivo. Trial n. 1. Microtubers of E 1587, MN 274 and Désirée, obtained under inductive conditions (Vecchio et al., 1997), were subdivided in relation to genotype, diameter and days of permanence on plant (age) and were stored for 30 days at 20°C or 4°C in the dark. After this period microtubers were placed under diffuse light and 20°C. Each two days they were observed and the sprouting was recorded. After sprouting microtubers were dried at 80 °C during 48 hours and analysed for mineral composition. Trial n. 2. Minitubers of 12 genotypes were grown under three different environmental areas in relation to altitude and growing season. The environmental effects on genotypes were evaluated by means of dormancy length. Results and discussion. The results outlined by this research indicate that thermal sum accumulated during tuberisation significantly affect tuber dormancy length. In fact, microtubers and tubers with a higher total day degrees sprout faster than those with lower values. Conclusion. This paper highlights the possibility to select genotypes per tuberisation earliness to be introduced in extra-seasonal potato cultivation typology in order to promote a sustainable planning of seed tuber production systems.