Influence of arbuscular mycorrhizal fungi on vegetative growth of avocado rootstocks

The objective of the present study was to evaluate the influence of six arbuscular mycorrhizal fungi (AMF) species (Glomus clarum, Scutellospora heterogama, Glomus etunicatum, Acaulospora scrobiculata, Gigaspora margarita and Glomus manihotis) on vegetative growth, mineral nutrition and carbohydrate contents of avocado (Persea sp.) rootstocks. These were cultivated in 5 L bags of black polyethylene containing substrate mixture of soil + silica sand + decomposed bark residue of acacia (Acacia mearnii) (2:2: 1, v:v:v). The rootstocks were kept in a sombrite (70% shading) greenhouse. Two months after AMF inoculation, the results indicated that AMF influence on avocado rootstocks growth is variable depending on AMF species. S. heterogama, A. scrobiculata and G. etunicatum were more effective, resulted in good nutrition and carbohydrate contents of avocado rootstocks, and consequently resulted better vegetative growth of plants. G. clarum only increased stem height of the rootstocks, while G. manihotis did not affect vegetative growth of avocado rootstocks. G. margarita was harmful to avocado rootstocks growth.