EFFECT OF HOST OR NON-HOST PREVIOUS-CROP IN GROWTH AND MYCORRHIZAL PROPAGULE IN WHEAT IN CHILEAN ANDISOL AND INCEPTISOL SOILS

Abstract

Arbuscular mycorrhizal (AM) fungi are obligate symbionts that improve nutrient absorption of plants. Including non-mycorrhizal plants in crop rotations as previous-crops can affect the symbiosis. The objective of this work was to study the influence of prior crop with an AM host or a non-host plant on the mycorrhizal propagule number, growth and nutrient uptake in wheat grown in the second year under greenhouse conditions. Oats, lupin and rapeseed were seeded the first year in an Andisol and an Inceptisol of La Araucanía Region, Chile, followed by wheat in the second year. The treatments were: oats-wheat (A-T), lupin-wheat (L-T) and rapeseed-wheat (R-T). The highest above ground biomass, number of inflorescences of plants, and P and Fe contents in leaves were obtained in L-T (cropping with a non-host followed by a host plant) in an Andisol. A significant increase in the content of Mg and K in wheat was observed in the A-T treatment in an Inceptisol. Regarding mycorrhizal parameters, the highest root colonization (35%) in wheat was observed in L-T in the Andisol, while the A-T treatment recorded the highest spore number but the lowest root colonization (19%). The highest phosphatase activity of wheat roots was observed in R-T in both types of soils, while the lowest value recorded in L-T in the Andisol. It is was concluded that growing wheat after a non-mycorrhizal host plant, like rapeseed, decreases the number of mycorrhizal propagules (spores) in both Andisol and Inceptisol, while pre-cropping with host plants increases the propagule number in wheat.