Fruit yield of three varieties of Fragaria ananassa related to degree of colonization by arbuscular mycorrhizae and other fungal endophytes, Tucumán, Argentina. Radical histological response to the interaction

Abstract

The province of Tucumán contributes 60 % of its strawberry production to the Central Market of Buenos Aires. In the root system of plants there are arbuscular mycorrhizal fungi (AMF) and fungi such as dark septate endophyte (DSE) that are symbiotically associated and related to production. The objectives of this work were to evaluate fruit performance of Camarosa, Sabrosa and Ventana varieties, related to the degree of colonization by AMF, DSE and another unknown septate fungus (USF); to quantify and characterize the radical colonization among the varieties; and to analyze the radical histological response of the interaction, during two crop seasons. Roots were treated according to conventional techniques. For the three varieties, yield and colonization by AMF, DSE and USF were quantified. Yield analysis showed
that Camarosa variety had the highest productive potential in the two seasons. In the 2011 campaign, the highest increase in total fruit yield for the three varieties and the lowest percentage of mycorrhizal colonization were observed; this could be related to a high phosphorus content (44 ppm) in the soil. Cells of the cortical parenchyma showed colonization by AMF (Arum and Paris), DSE and USF in all three varieties. Primary growth evidenced diarch and tetrarch stela in Camarosa variety, diarch in Sabrosa and diarch to pentarch in Ventana. The co-occurrence of AMF, DSE and for USF, in strawberry varieties, raises questions about the functional relationship of the association.