1. Naomi Asomani Antwi Matilda Ntowah Bissah May, 2016

2.  Introduction  Background  Materials and Methods  Results  Conclusions

3. Plant genetic resources (PGR):  comprise the set of gene combinations as a results of the evolution of species.  have potential for current or future agricultural use.  are landraces, improved varieties, products of biotechnology, etc.  PGR conservation is necessary to prevent genetic erosion.

4. PGR are conserved  in situ - forest reserves, on-farm  ex situ - seed storage, field genebanks, in vitro slow-growth, cryopreservation  or in a combination of both methods (Jaramillo et al., 2002).

5.  In vitro techniques are employed for conservation of recalcitrant seeds, vegetatively propagated species and biotechnology products (Engelmann, 2011). In vitro conservation of PGR - complements field conservation and - space saving - phytosanitary method for germplasm maintenance and exchange - protects PGR from natural disasters, disease and pest outbreak.

6. Cassava  major carbohydrate source in the tropics.  The leaves provide a cheap source of protein and vitamins (Umuhozariho et al., 2014).  It is also used as livestock feed  raw material for the cassava industry.

7. Field genebank Cryopreservation Tissue culture (slow-growth)

8.  Cassava has a narrow genetic basis for crop improvement.  Cultivation of released cassava varieties, climate change, disease and pest incidences, etc. can lead to loss of genetic diversity in cassava.  Conservation of cassava genetic resources will ensure that their diversity is captured for crop improvement and future use.

9. to showcase the in vitro conservation activities carried out on cassava genetic resources held at the CSIR - Plant Genetic Resources Research Institute, Ghana.

10. Media content: I. MS formula for basal salts II. Vitamin mix III. Sucrose – 30 g/l IV. Bacteriological agar - 8g/l Plant growth regulators: Benzylaminopurine (BAP) - 0.05mg/l Naphtalene acetic acid (NAA) - 0.01mg/l

11. Shoots soaked in fungicide

12. - washing in 35% ethanol for 10 minutes - washing in 10% commercial bleach for 10 minutes - washing in sterile distilled water Surface sterilization in laminar flow hood

13. 1. Prepared explants 3. Nodal segments of cassava shoots in growth medium 2. Transferring to medium

14. Temperature - 25 ± 1°C Lighting - fluorescent light (18.5 μmol.m-2.s-1) Photoperiod - 16/8 hours day dark Relative Humidity - 60 - 70%

15. Regenerated plantlets are cut into nodal portions and subcultured onto fresh medium

16.  by periodic subculturing at a minimum of six months intervals.

18. Microbial contaminations Stunted growth Necrosis

20. 1. CSIR – PGRRI has hold the national in vitro cassava collection. 2. Current inventory 241 cassava accessions are under in vitro conservation, 232 landraces and 9 released varieties. 3. The in vitro cassava collection is maintain by periodic subculturing of accessions. 4. Loss of accessions from in vitro conservation is due to necrosis, microbial contaminations, hyperhydricity and stunted growth.