Effect of the Application of Microorganisms on the Nutrient Absorption in Avocado (<i>Persea americana</i> Mill.) Seedlings

Abstract

Avocado is a fruit crop of high economic importance for Ecuador, both locally and for exportation. Fuerte and Hass varieties are cultivated, both of which are grafted onto rootstocks from the cultivar Criollo. The growth of rootstocks in the nursery is a critical stage in the production of avocado plants, and application of beneficial microorganisms could be used to improve plant nutrition and growth of the rootstocks. In this research, the effect of inoculation of Trichoderma harzianum or Glomus iranicum var. tenuihypharum on avocado rootstock seedlings (cultivar Criollo) was evaluated. Application of T. harzianum significantly increased the absorption of N5+ and Mg2+ in the roots; while in the aerial parts (leaves and stem), it increased the absorption of N5+, Ca2+, Mg2+, Mn2+ and Cu2+. On the other hand, G. iranicum var. tenuihypharum significantly increased the absorption of Ca2+ and Fe3+ in the root; but no major effect was observed in the aerial part. However, a positive tendency toward an increase in the amount of P5+ was observed in the root; while in the aerial part this trend was observed for N3- and Ca2+ absorption. Neither of the two microorganisms influenced the absorption of S4+, an element that was present at stable levels in the whole plant. In conclusion, the applied microorganisms produced an increase in absorption of several macro and micronutrient in Criollo avocado rootstock seedlings.