Abstract
Introduction - Many of species of Ziziphus are underutilized crops despite their potential interests in agroforestry systems. Except for Ziziphus mauritiana, the effectiveness of arbuscular mycorrhizal fungi (AMF) on growth and mineral nutrition of Ziziphus spp. is not known. The aim of our study was to evaluate the mycorrhizal dependency (MD) of Ziziphus spp. in greenhouse conditions. Materials and methods - Three isolates of AMF were used: Rhizophagus irregularis isolate IR27, Funneliformis mosseae isolate DAOM227131 and Rhizoglomus intraradices isolate DAOM197198, on seven species of Ziziphus: Z. mauritiana, Z. lotus, Z. spina-christi, Z. mucronata, Z. amphibia, Z, abyssinica and Z. sphaerocarpa. Plants were grown in nursery receiving 20 g portions of a crude inoculum of AMF. The experiment was set up as a 4 x 7 factorial design consisting of three AMF, one control (disinfected soil without inoculum) and seven Ziziphus spp. Results and discussion - Inoculation by AMF significantly improved growth and mineral nutrition of Ziziphus spp., particularly the P nutrition. Mycorrhizal dependency values of Ziziphus spp. declined with AMF in the following order: R, irregularis (69.51%), R. intraradices (63.58%) and R mosseae (52.45%). Total length of AMF hyphae in soil samples from inoculated treatments was significantly higher in all Ziziphus spp. with II, intraradices combinations. The differences of MD among the tested Ziziphus spp. seem to be due to differences in the development of hyphal length in the soil and in P uptake by the external hyphae. Conclusion - Rhizophagus irregularis constitutes a promising tool for the production of higher quality nursery stock with expected improved performance of Ziziphus spp. in agroforestry systems.