Improved genotypes and fertilizers, not fallow duration, increase cassava yields without compromising arbuscular mycorrhizal fungus richness or diversity

Growth and phosphorus uptake by cassava in P-deficient soil in response to mycorrhizal inoculation

“…Cassava presented a positive response to AMF inoculation in disinfected soil (Howeler et al, 1982), but the benefits of AMF inoculation have not been clarified in natural soil conditions (Ceballos et al, 2013;Heberle et al, 2015) as verified in the present study. In the disinfected soil, a rate of 200 spores per plant Rhizophagus clarus promoted cassava growth similar to that in natural soil conditions, corroborating previous studies that cassava is naturally associated with AMF (Balota et al, 1999;Straker et al, 2010;Aliyu et al, 2019) and is highly dependent on them for growth (Balota et al, 1999;De Bauw et al, 2021).…”

“…In the cassava crop (Manihot esculenta Crantz), P fertilization is considered essential for improving cassava storage root yield (Peña Venegas et al, 2021). However, as cassava has thick absorbent roots and few root hairs, it has a low root surface area for nutrient uptake (Silveira et al, 2015); therefore, it is one of the crops most dependent on the association with arbuscular mycorrhizal fungi (AMF) (Balota et al, 1999;Silveira et al, 2015;De Bauw et al, 2021). Arbuscular mycorrhizal fungi occur naturally in soils, and mutualism between plants and AMF occurs in 72 % of terrestrial plant species (Brundrett and Tedersoo, 2018).…”

“…Studies on AMF in cassava crops, especially in African and South American countries (Fagbola et al, 1998;Balota et al, 1999;Okon et al, 2010;Straker et al, 2010;Ceballos et al, 2013;Heberle et al, 2015;Begoude et al, 2016;De Bauw et al, 2021;Peña Venegas et al, 2021) have shown that there is a diversity of AMF species associated with the root system of cassava, predominantly within the genera Acaulospora, Entrophospora, Rhizophagus, Glomus, Gigaspora and Scutellospora (Balota et al, 1999;Straker et al, 2010;Begoude et al, 2016;Chukwuka et al, 2017). However, some studies indicated variability in the response of cassava to mycorrhizal inoculation depending on the cassava variety and the AMF strain in the inoculant (Aliyu et al, 2019;Peña Venegas et al, 2021).…”

“…There are studies indicating that management practices that increase the abundance of native AMF in the soil may be more efficient than the inoculation of exotic AMF (Verbruggen et al, 2013). However, it is not in all situations that cassava growth or yield increase due to the previous adoption of management practices that favor the native AMF multiplication in the soil (Heberle et al, 2015;De Bauw et al, 2021). For example, the practice of fallow can increase the native AMF population in terms of richness and diversity and not improve the cassava yield (De Bauw et al, 2021).…”

“…However, it is not in all situations that cassava growth or yield increase due to the previous adoption of management practices that favor the native AMF multiplication in the soil (Heberle et al, 2015;De Bauw et al, 2021). For example, the practice of fallow can increase the native AMF population in terms of richness and diversity and not improve the cassava yield (De Bauw et al, 2021). In contrast, field studies showed that cassava response to AMF inoculation is not necessarily restricted to conditions of low P availability (Peña Venegas et al, 2021); it is complex and depends on factors such as cassava variety, soil heterogeneity and the fungal strains of the inoculant (Aliyu et al, 2019;Peña Venegas et al, 2021).…”