In vitro conservation of Ipomoea batatas (L.) Lam cultivars by minimum growth with the use of mannitol

In vitro conservation of Ipomoea batatas (L.) Lam allows the exchange of germplasm and its availability for breeding programs. The objective of this work was to determine the effect of mannitol and abscisic acid in the conservation through minimum growth of I. batatas cultivars from INIVIT Germplasm Bank. Treatments included abscisic acid (ABA) (5 and 10 mg l-1) and mannitol (1.0, 1.5 and 2.0%) in a basal MS culture medium, the combination of ABA (10 mg l-1) and mannitol (1.0 , 1.5 and 2.0%). As controls were used the MS basal culture medium and MS with sorbitol (1.0%) and glucose (1.0%). In the cultivars 'Cautillo' and 'INIVIT BS 16-2006' the best results of survival, growth decrease and green but small leaves were obtained in the treatments that contained the basal culture medium with mannitol (10, 15 and 20%) . Growth of the explants was not achieved in culture media with abscisic acid. The MS culture medium with 2 mg l-1 of thiamine, 100 mg l-1 of myo-inositol and 1.0% of mannitol, allows the in vitro conservation of sweet potato cultivars between six and eight months.