Effect of Substrate Type on Survival and Growth of Sweet Potato Vitroplants Under Acclimatization

: The lack of healthy planting materials is one of the major constraints of sweet potato cultivation in Benin. One of the solutions to this problem is the use of vegetal biotechnology through micropropagation. At the end of the production of vitroplants, a crucial phase consists in acclimatizing them before their transfer to the real environment. The type of substrate used plays an important role in the success of acclimatization. This study aims at evaluating the effect of the type of substrates on the survival and growth of sweet potato vitroplants in acclimatization of the two accessions (Mèché and Bombo vôvô). For this, three substrates were assessed. These are Potting soil alone, Potting soil + Sawdust, and potting soil + Charcoal powder in proportion 2:1. These substrates were first sterilized separately in an oven at 150°C for 2 hours. The experiment was conducted in the greenhouse of Central Laboratory of Vegetal Biotechnology and Plant Improvement of the Faculty of Sciences and Techniques of the University of Abomey-Calavi following a model of random complete blocks in split plot design. The results show that the type of substrate influences the success of acclimatization in terms of survival rate, the gain of size and the number of neoformed leaves (p= 0.0033; 0.0019 and 0.0001). The Potting soil + Charcoal powder substrate influenced these parameters better than the other two with 95%, 3.13 cm and 3.165 respectively for survival rate, size gain and the number of neoformed leaves. It was followed by the Potting soil + Sawdust substrate. Acclimatized plants have been successfully introduced into the field, proving that this technique is fruitful in the increase of the production of healthy cuttings and make them available to farmers. The protocol used in this study can be applied in the acclimatization of sweet potato vitroplants.