Benefits of Breeding Crops for Yield Response to Soil Organisms

Assessing the Consequences of Microbial Infection in Field Trials: Seen, Unseen, Beneficial, Parasitic and Pathogenic

“…Many are root-inhabiting, facilitating acquisition of specific nutrients or water in return for assimilates, mainly carbon. Mycorrhizae are classic examples of these but high soil disturbance conditions coupled with high levels of nutrients tend to mitigate against their presence and efficacy, particularly in crops such as the cereals that are not highly mycorrhizal anyway [82]. However, the response to soils and their microbial communities is seldom a factor in breeding programmes but there is much potential, particularly if fungicidal treatments are more contained, reduced or targeted [82].…”

“…Mycorrhizae are classic examples of these but high soil disturbance conditions coupled with high levels of nutrients tend to mitigate against their presence and efficacy, particularly in crops such as the cereals that are not highly mycorrhizal anyway [82]. However, the response to soils and their microbial communities is seldom a factor in breeding programmes but there is much potential, particularly if fungicidal treatments are more contained, reduced or targeted [82]. This potential has been described as the "evergreen revolution" where the beneficial relationships between crop plants and their symbionts, combined with their influence on soil chemistry, physics and biology, can be exploited as the means to achieving "sustainable intensification" [82].…”

“…However, the response to soils and their microbial communities is seldom a factor in breeding programmes but there is much potential, particularly if fungicidal treatments are more contained, reduced or targeted [82]. This potential has been described as the "evergreen revolution" where the beneficial relationships between crop plants and their symbionts, combined with their influence on soil chemistry, physics and biology, can be exploited as the means to achieving "sustainable intensification" [82]. However, even some fungi normally known as pathogens can have beneficial effects on plant biomass when they fail to transition to the symptomatic or pathogenic trophic state [9].…”

How can we exploit above–belowground interactions to assist in addressing the challenges of food security?

“…Previous potato growth in a field can increase the prevalence of root knot nematodes (reviewed in Trudgill et al, 2003), thereby increasing the need to plant varieties with greater resistance to root knot nematode. Site history can also influence the prevalence of other partners – for example, soil disturbance such as tilling can reduce the diversity and abundance of AM fungi (Fester and Sawers, 2011; Bennett et al, 2013a), which could have significant consequences in some of the scenarios above. For example, AM fungi have been shown to enhance belowground induced defense responses to the root herbivore vine weevil (Bennett et al, 2013b), so limiting the presence of AM fungi by tilling could increase the susceptibility of crop plants to vine weevil in the field.…”

“…As a result, utilizing mutualisms such as rhizobia, AM fungi, and endophytes could improve plant nutrition and defense against enemies. However, research suggests that breeding practices have selected against associations with the below-ground mutualists AM fungi and rhizobia (Bennett et al, 2013a; but see Lehmann et al, 2012). Modern breeding has often occurred under optimal nutrient conditions thereby making nutritional mutualists redundant, and under high soil disturbance which reduces the prevalence of soil mutualists (Fester and Sawers, 2011; Bennett et al, 2013a).…”