An Alternative Tissue Culture Media for Potato (Solanum tuberosum L.) Micro Propagation

The cumbersome nature of tissue culture technique contributes to the low adoption of the technique. This work aims at developing an accessible alternative tissue culture medium for potato micro propagation. The inorganic components of the conventional MS medium were replaced with a common source of nitrogen, phosphorus and potassium (NPK) to regenerate in vitro plantlets of six improved Cameroonian potato varieties selected from meristem-derived plantlets. These varieties included: Cipira, Mafo, Bambui wonder, Irad 2005, Jacob 2005 and Tubira. Five (5) nodes each per replicate per variety were cultured on both media and allowed to grow at a temperature of 21 ºC and 16hrs/day photoperiod for 28 days.Number of nodes sprouting, number of nodes rooting, plant height, and number of nodes per plantlet were recorded weekly in 4 weeks. Results shows that both media regenerated vigorous plantlets with shoots and roots. Using the Statistical Package for Social Science (SPSS), analysis of variance revealed slight significant differences (p≤0.05) between varieties and media in terms of sprouting and rooting Height of plantlets on NPK medium ranged from 29.85 mm (Cipira) to 45.25 mm (Irad 2005) meanwhile, on MS medium it ranged from 47.93 mm (Bambui Wonder) to 65.70 mm (Jacob 2005). Average number of nodes ranged from 2.59 (Tubira) to 3.63 (Mafo) on fertilizer medium while on MS medium it ranged from 2.70 (Irad 2005) to 4.20 (No significant difference at p≤0.05). in conclusion; the developing countries can replace the inorganic components of MS medium with inorganic fertilizer (NPK) for in vitro multiplication of potato

Diseases Caused by Pectobacterium and Dickeya Species Around the World

202

Biological control of cacao diseases

This chapter discusses the advances in biological control of cacao diseases over the last 15 years. Most attention has been focused on biological control of frosty pod rot (Moniliophthora roreri), witches' broom (Moniliophthora perniciosa) and black pod disease (Phytophthora spp.). Research on biocontrol of other diseases in the cacao phyllosphere or rhizosphere is scarce or in its infancy. There is, however, a steady increase in information regarding the factors influencing and the mechanisms underlying biological control of cacao diseases as well as practical aspects such as inoculum production, formulation and application. There has been a clear shift away from inundative approaches using epiphytic BCAs towards more classical biocontrol approaches using bacterial and fungal endophytes as well as vesicular arbuscular mycorrhiza. These have the advantage that they can permanently establish themselves in the cacao tree. Moreover, besides direct competition for space and nutrients, antibiosis and mycoparasitism, through induced resistance and growth promotion, endophytes have a larger arsenal of mechanisms through which they can help protect their host. Endophytic BCAs could thus provide more effective and sustainable disease control. Recent advances in our understanding of the mechanisms through which endophytic biocontrol agents can reduce pest and disease impact provide possibilities for innovative disease control strategies, including combination therapies together with natural or chemical products. Continued work on production, formulation and application is also necessary in order for biocontrol to become economically interesting. However, biological control will not become a stand-alone solution for disease control but should become part of integrated pest management strategies, with cultural management as a central and reinforcing pillar. (Résumé d'auteur