|Flagship 1: Managing productivity is focuses on interventions that are intended to improve the productivity of our crops.|
Crop biotic interactions include beneficial and detrimental relationships, and some of these biotic relationships act synergistically with abiotic constraints.
The role of nitrogen fixation in improving legume crop performance, soil health and their contribution to following or companion crops as well as providing forage for animals is also part of the activity focus.
The way that constraints to the cultivation of legume crops can be overcome includes the analysis of crop physiology, agronomy and crop management. Notably this is in terms of the identification and quantification, of constraints such as drought, insect pest damage or other biotic and abiotic stresses.
Insect pests are a major constraint on legume production and have been largely intractable genetically, notably in the case of polyphagous insects in the genera Helicoverpa and Maruca. Management practices that include rearing and deployment of parasitoids and/or the use of bio-pesticides are an opportunity that could have a major impact independent of the availability of sources of genetic resistance or tolerance. This corresponds to our Product Line 5 (PL5) on integrated pest management.
Crops have associations with a range of microbes, some are pathogens but others promote growth either directly (eg, Rhizobium) or indirectly by competing with pathogens or negatively impacting on pests (eg, certain actinomycetes and/or stimulate plant growth - Azospirillum spp). These organisms and their management are therefore significant levers in managing the performance of grain legume crops. Some of these crop-microbe interactions are also impacted by the environment, for example Nitrogen fixation is modulated by phosphorous availability, water and temperature as well as plant maturity. Studies on N fixation (PL4) are allied to the Bill & Melinda Gates Foundation-supported N2 Africa project where this is active.
There are major uncertainties associated with projected climate change with some areas projected as becoming wetter and others drier, but overall an increase in temperature is likely to be a general concern. Elevated temperature (especially night time temperature) can have a major impact on plant fertility (ie, seed set). So understanding the mechanisms underlying existing variation in temperature sensitivity of yield is needed in order to combine mechanisms and strategies. Moreover, temperature changes also modify agro-ecologies especially microclimate, and can favor an increase in pathogen and pest reproductive fitness leading to rapid build-up of populations and consequently disease and pest outbreaks. The abiotic consequences of climate change affect pests and pathogens as well as our target crops, so this also has a consequence for crop responses to and challenges by biotic stress.