Effectiveness of different arbuscular-mycorrhizal fungi on initial and post-transplant growth and bean yield of coffee tree seedlings

Abstract

The effects of inoculation of coffee tree seedlings with different arbuscular-mycorrhizal fungi on seedling raising (nursery) and post-transplant growth stages, survival and bean yield under field conditions are reported. Seedlings were inoculated with Gigaspora margarita, Glomus clarum and with other thirteen fungal assemblages of indigenous mycorrhizal 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 pots in the greenhouse. Responses at these two stages showed no major differences among the fungal treatments. Survival and growth of ouplanted seedlings were increased by all fungal treatments. However, bean yield was significantly increased only by G.margarita and by four indigenous fungal assemblages. Mean yield increase of these treatments was on the average 100% higher than non-inoculated control.