Breeding crops that utilise nutrients more efficiently
The future expansion of Irish agriculture needs to be seen in the context of global climate change. Agricultural practices will need to be sustainable in terms of both inputs and emissions (e.g. fertilisers and greenhouse gases), and increasing weather volatility means that crop varieties must also be able to withstand a more diverse array of adverse environmental conditions.
Nutrient availability and recovery by plants is a key factor affecting (often limiting) crop yield potential. In order to achieve more agronomically and environmentally sustainable crop production systems, achieving high levels of N use efficiency (NUE) is critical. Nitrogen uptake by crop plants grown in soil is greatly influenced by root morphology, soil properties, climate, cultural and management practices, and plant species. Many studies have focused on cultural and management practices (changing fertiliser rates, timings and placement) to optimise nutrient availability for crops, however, limited knowledge exists on the variability within crop species for NUE and adaptability to low N environments.
Nitrogen fertiliser is a major input in cereal growing. VICCI is utilising large experimental populations of wheat and barley that have been developed by collaborating research organisations in the UK (a winter wheat MAGIC population from NIAB and a large barley collection from the James Hutton Institute). These populations have been extensively genotyped, allowing the cost effective identification of genes and loci determining NUE efficiency under Irish growing conditions. In addition, VICCI researchers are testing approaches based on novel breeding techniques such as CRISPR/Cas9 to develop low grain-N cereals that can provide high energy grain suited to monogastric (pigs, chickens) feeding, with low nitrogen fertiliser requirements combined with reduced emissions of nitrate, ammonia and nitrous oxide.
While N is a key nutrient for plant growth and development, uptake over and above that needed for biomass production is required to supply the formation of grain protein during grain filling. If there is insufficient N available during grain filling the removal of N from the crop canopy results in premature canopy senescence and reduced yield. Removing or reducing this N requirement for grain storage proteins should reduce the requirement for 'luxury' N uptake. There is a need and opportunity to develop for Irish cereal growers novel lines of winter wheat that can provide high energy grain suited to monogastric (pigs, chickens) feeding, and with low nitrogen fertiliser requirements. The expected gains from such varieties would be reduced costs of crop nutrition combined with reduced emissions of nitrate, ammonia and nitrous oxide.