In vitro genebank is an ex-situ conservation method that basically allows safeguarding of valuable genetic diversity of a particular crops, outside their original or natural habitat, under artificial growing (in vitro). Achieved with slow growth conditions, in vitro conservation involves maintenance of plant explants in a sterile, pathogen-free environment and mostly applied to vegetatively propagated crops that produce non-orthodox, heterogenous and/or recalcitrant seeds (sometimes do not produce seeds). This modern plant tissue culture technique has already been applied on more than 1000 species for mass propagation (multiplication) or planting material production (microtubers, nursery), haploidization, micro-grafting (in breeding), bioengeniering (genetic transformation) and for rescue of endangered material/species. In general, more economical and less risky in a long-term perspective; as compared to field collections, in vitro genebanking is mainly seen as medium term storage (MTS), with particular culture conditions to slow down the plant growth (slow growth conditions): growth retardation, minimal containment, relatively cold temperature and short photoperiod. In vitro conservation can be associated with long term storage (LTS), or cryopreservation, at ultra-low temperature using cryogenic techniques (in liquid Nitrogen at -196oC).
The IITA Genetic Resources Center (GRC) is based at IITA headquarter in Ibadan, Oyo state, Nigeria. It consists of three sections. One of which is the in vitro genebank (others are seed bank and field bank sections). At IITA, in vitro conservation is being used for vegetatively propagated crops such as cassava (Manihot exculenta, crantz), Yam (Dioscorea spp.), plantain and Banana (Musa spp.). The principle of in vitro genebank is to safeguard a duplicate copy, as complementary system, of the genetic diversities of these staple vegetative propagated crops already conserved on the field bank.
In vitro conservation bears many advantages for clonal crops maintenance. It firstly leads to the reduction of genetic loss risks (frequent in the field banks) and constitutes a viable alternative to complement and reduce the large space and hand labor required for field banks. In vitro plant tissue culture is a complementary conservation system that gives the possibility to clean the germplasm from diseases and pest via meristem culture and/or other therapies (thermo-, cryo- and chemo-treatment), in collaboration with IITA Germplasm Health Unit (GHU). This latter advantage makes it easier for germplasm exchange, in collaboration with IITA Germplasm Health Unit (GHU) and Nigerian Agricultural Quarantine Services (NAQS), to ascertain that the germplasm is transferred in line with standard phytosanitary regulations, as well as simpler plant material transport. The other advantage of the in vitro conservation system, over field bank, is the security of the conserved germplasm. Also, in vitro plant tissue culture is a powerful tool for safer and faster way to multiply large quantity of material and for various biotechnological application in breeding and other plant biological domains.
In the in vitro genebank of IITA GRC, both the improved lines and landraces of the above mentioned crops are conserved for breeding, training, research use and production. As at November 2018, in vitro genebank of IITA holds more than 2500 cassava accessions, as many yam accessions and more than 500 accessions of Plantain/banana. The germplasm conserved is available and the majority meets phytosanitary requirements making it accessible worldwide. To access germplasm conserved in vitro at IITA, request can be maded through GRC/IITA contact persons and will be distributed in line with the multilateral system (MLS) of the International Treaty on Plant Genetic Resources for Food and Agriculture under the auspice of the Food and agriculture organisation (FAO) of the united nations (UN),
The facilities available at the GRC in-vitro genebank includes plant growth and conservation rooms, culture media preparation room, transfer (aseptic handling) room and washing/autoclave room; with all relevant in vitro laboratory relevant equipment (autoclave, laminar flow hoods culture shelves, pH meter, weighing balances, glasswares, fridges, growth cabinets, water purification system, glass washing machine and dryer). The human resources is composed with well-trained and skillful personnel, competent to carry out in vitro plant tissue culture work in compliances with minimum quality and risk management system (laboratory best practices, safetry and security).