Produzione di tubero seme: tecniche di valutazione di nuovi cloni e di vecchie varietà di patata

Introduction. Given the gap between seed potato needs and availability at national level, the research activity, inserted in the ambit of the project "Potato Genetic Improvement" funded by the Italian Ministry of Agriculture and carried out by the Department of Agronomy and Land Management of Faculty of Agriculture of Florence, aimed to define rapid techniques of selection in order to evaluate agricultural performances of potato new clones and landraces by means of different methodologies. In parallel, has been carried out an activity of conservation of collected genotypes. Materials and methods. The experimental protocol was organised in four distinct experimental activities: 1) assessment of in vitro behaviour of potato new clones and landraces by means of standardised in vitro techniques; 2) assessment of semivivo behaviour of potato new clones and landraces by means of standardised techniques; 3) full field trials adopting a randomised block design in order to assess the performances and the reaction norm of selected potato clones and landraces grown under different climatic conditions and cultivation typologies; 4) recover, in vitro introduction, virus elimination,in vitro multiplication and conservation of collected genotypes by means of standardised techniques. Results and discussion. In vitro behaviour was significantly influenced by growing conditions and genotype. Specifically short-day conditions and the presence of CCC in the medium induced a higher tuberisation. Furthermore some genotypes showed better tuberisation performances under long-day conditions. Semivivo trials substantially indicated a similar response of the different clones and landraces in terms of minituber production per plant. The response to different environmental conditions was heterogeneous with the lowest production registered under extra-seasonal cultivation and the highest in Camigliatello Silano. In particular, some clones reached the production level of the control variety Désirée. Conclusion. The results obtained with the different techniques indicate that the genetic material is highly diversified highlighting the possibility of its utilisation in different and typical environmental conditions of national potato crop. Moreover the comparison between the results obtained in vitro, semi vivo and full field conditions and, in particular, the behaviour concordance among some clones, highlight a concrete possibility of exploiting the rapid and low cost features of in vitro culture to select potato genotypes for productivity. Also the semi vivo technique, although more expensive, could represent a valid alternative in support to selection activity. Referring to earliness, in vitro technique could provide an important selection tool, but it would be necessary to deeply define the parameters for earliness assessment.