J.M. Jefwa

Inoculation of tomato seedlings with Trichoderma Harzianum and Arbuscular Mycorrhizal Fungi and their effect on growth and control of wilt in tomato seedlings

A green house study was conducted to investigate the ability of an isolate of Trichoderma harzianum (P52) and arbuscular mycorrhizal fungi (AMF) in enhancing growth and control of a wilt pathogen caused by Fusarium oxysporum f. sp. lycopersici in tomato seedlings. The plants were grown in plastic pots filled with sterilized soils. There were four treatments applied as follows; P52, AMF, AMF + P52 and a control. A completely randomized design was used and growth measurements and disease assessment taken after 3, 6 and 9 weeks. Treatments that significantly (P < 0.05) enhanced heights and root dry weights were P52, AMF and a treatment with a combination of both P52 and AMF when compared the control. The treatment with both P52 and AMF significantly (P < 0.05) enhanced all growth parameters (heights; shoot and root dry weight) investigated compared to the control. Disease severity was generally lower in tomato plants grown with isolate P52 and AMF fungi either individually or when combined together, though the effect was not statistically significant (P0.05). A treatment combination of P52 + AMF had less trend of severity as compared to each individual fungus. T. harzianum and AMF can be used to enhance growth in tomato seedlings.

Acclimatization and growth of tissue cultured banana co-inoculated with microbiological and chemical commercial products in different soils in Kenya

The efficacy of co-inoculation of microbiological products and combining them with a chemical stimulant in enhancing survival and growth of tissue culture banana under different soil conditions was investigated in the greenhouse. Tissue cultured banana (Gros Mitchel cv.) was inoculated with products containing Bacillus spp., arbuscular mycorrhizal fungi (AMF), Trichoderma harzianum, Myconate (chemical stimulant) and their combinations. Two soil types (Rhodic Ferralsol and Vertisol) were used at the hardening and potting phases and inoculation of plants was done at both phases. Plant growth was assessed at an interval of two weeks. Destructive harvesting was done and mycorrhizal colonization, root and shoot biomass and shoot nutrient uptake were assessed at the end of nursery phase. The effect of the products on the measured parameters depended on soil type with Vertisol being most receptive to inoculation. The combination of Bacillus spp. with AMF or Myconate or T. harzianum in the Vertisol gave the most significant increase in plant growth by over 28, 24 and 14%, respectively and in plant biomass accumulation by over 34, 46 and 33%, respectively compared to the control. Mycorrhizal colonization was not significantly affected by product inoculation in the two soils. In the Rhodic Ferralsol, the combination of arbuscular mycorrhizal fungi with T. harzianum promoted the highest uptake of zinc, boron, magnesium and phosphorus; T. harzianum+ Bacillus spp. promoted the highest uptake of potassium, while AMF+ Myconate promoted the highest uptake of calcium. In the Vertisol, the combination of Bacillus spp. with arbuscular mycorrhiza fungi gave the highest uptake of phosphorus, magnesium, calcium and boron; Bacillus spp.+ Myconate gave the highest uptake of potassium, while singly applied AMF gave the highest uptake of zinc. Results demonstrate that tissue cultured bananas’ survival and growth can benefit from co-inoculation of arbuscular mycorrhizal fungi and Trichoderma or Bacillus or a chemical stimulant during the nursery phase. The effect of coinoculation is however depended on soil type.

International Workshop of the African Network on Mycorrhiza (AFRINOM 1): advancing plant–microbe interactions in crop nutrition, integration of mycorrhiza into agroecosystems

The African Network on Mycorrhiza (AFRINOM, http:// senegal.ird.fr/afrinom) was created following an international workshop on “Mycorrhiza: a biological tool for sustainable development in Africa,” held in Dakar, Senegal, in 2011 (Bâ et al. Mycorrhiza 2011). The general objectives of AFRINOM are to strengthen research, encourage cooperation, and promote exchange of information on mycorrhiza in Africa. The network, which consists of 135 members from 31 countries, encourages the development of joint research activities between researchers in Africa and Europe, America, Oceania, and Asia. It also gathers data and published information on mycorrhiza in Africa and provides information about laboratories working on mycorrhiza in Africa and a database on cultures of ectomycorrhizal and arbuscular mycorrhizal fungi from Africa and abroad. The International Workshop of AFRINOM 1 on “Advancing plant–microbe interactions in crop nutrition, integration of mycorrhiza into agroecosystems” was organized in Nairobi, Kenya, October 22–26, 2012, as part of the ISFMAfrica 2012 conference on “Integrated Soil Fertility Management in Africa: from microbes to markets.” Thirty-one participants from 13 countries attended the workshop, which included oral presentations, poster sessions, and excursion. Abstract of all talks and posters can be found on the AFRINOM website. The workshop objectives were to analyze innovative mycorrhizal interventions (e.g., production of mycorrhizal inoculants) and their impact in land management strategies benefiting smallscale agriculture in Africa. The contents addressed included the following: integration of mycorrhiza into agrosystems, optimization of mycorrhizal interventions and adaptation, mycorrhiza in ecosystems management, alternative interventions and bioprospecting tools, and strain selection and delivery. In the plenary session, Prof. Joanna Dames (South Africa) introduced challenges and future prospects of mycorrhizal agrotechnology for Africa and raised a fundamental question: why have we not embraced mycorrhizal technology and adopted it as standard agricultural practice in Africa? In her talk, she covered the many constraints linked to production of mycorrhizal inoculants, i.e., mass production, formulation, quality control, maintenance of culture collections, mycorrhizal fungal species/plant host matching, persistence among native strains, cost of the product for small-scale farmers, and farmer perception. In a session on integration ofmycorrhiza into agroecosystems, H. Dupre de Boulois (Belgium) presented the potentials and advantages of monoxenic AM fungal cultures, and concluded that present knowledge is inadequate to proposemass production of mycorrhizal inoculants by this method. Amadou Bâ (Senegal) presented results on the domestication of different provenances J. M. Jefwa CIAT, Nairobi, Kenya