Comparison of indigenous and selected mycorrhiza in terms of growth increases and mycorrhizal dependency of sour orange under phosphorus and zinc deficient soils

The soils of Central Anatolia contain a high clay content, pH and low fertility, especially zinc (Zn) and phosphorus (P) levels, and this region also experiences less precipitation; consequently, crop production is primarily limited due to Zn and P deficiency. The objective of this study was to evaluate the effects of inoculating selected single arbuscular mycorrhizae (AM) and indigenous native mycorrhizae (INM), along with the application of P and Zn doses, on the growth and nutrient uptake of sour orange (Citrus aurantium L.) seedlings under sterile soil conditions. Our hypothesis was that citrus growth is dependent on AM fungi in terms of P and Zn nutrition. A fully factorial experiment was set up to test the effects of mycorrhizal fungi, P and Zn doses, and two soils on the growth and nutrient uptake of sour orange under greenhouse conditions. In both soils, mycorrhizal inoculation increased certain growth parameters of citrus seedlings, such as shoot height, shoot and root dry matter, and root infection. Generally, mycorrhizae-inoculated seedlings grew better than the control plants; however, mycorrhizal inoculation also significantly increased plant tissue Zn and P uptake. In the absence of mycorrhizal inoculation, shoot and root dry matter production were severely affected by the application of P and Zn, and supplying adequate amounts of P and Zn significantly increased plant growth parameters. Under low P addition, Rhizoglomus clarum-inoculated plants exhibited an increased P concentration, up to 83%, and an up to 54% increase of Zn concentration. Under a high P level application, the increase of P and Zn concentration decreased. Inoculated citrus seedlings had high mycorrhizae dependency, which was significantly affected by the soil series and P, and only partially by Zn application. The results indicate that INM inoculation is as effective as R. clarum inoculation. © ISHS 2019