EFFECTIVENESS OF DIFFERENT ARBUSCULAR-MYC ORRHIZAL FUNGI ON INITIAL AND POSTTRANSPLANT GROWTH AND BEAN YIELD OF COFFEE TREE SEEDLINGS

The effects of inoculation of coffee tree seedlings with different arb uscular-mycorrhizal fungi on seedling raising (nursery) and post-trans plant growth stages, survival and bean yield under field conditions ar e reported. Seedlings were inoculated with Gigaspora margarita, Glomus clarum and with other thirteen fungal assemblages of indigenous mycor rhizal fungi, previously isolated from coffee, corn and soybean crops. Mycorrhizal inoculation improved seedling growth at nursery stage and also after they were transplanted to fumigated soil and to field plot . Growth increases due to inoculation were, on the average, below 100% at nursery stage and above 400% when seedlings were transplanted to p ots in the greenhouse. Responses at these two stages showed no major d ifferences among the fungal treatments. Survival and growth of ouplant ed seedlings were increased by all fungal treatments. However, bean yi eld was significantly increased only by G.margarita and by four indige nous fungal assemblages. Mean yield increase of these treatments was o n the average 100% higher than non-inoculated control.