Improved barley cultivars for better nutrient acquisition

Barley cultivars to cope with nutritional drought

With global environmental change it is essential to ensure resilience of farming systems. In the agricultural landscape of the future, effective use of water and nutrients by crops will be critical to the sustainability of farming systems.

The main objective of this research is to identify barley cultivars which cope with nutritional drought, the reduced availability of nutrients under predicted drier summer conditions. Understanding the interaction between plant responses to water availability and phosphorus deficiency will be crucial. Since many of the physiological responses associated with both stresses are shared, it is imperative that such responses are decoupled to identify the key drivers of relevant phenotypes.

This research employs state-of-the-art techniques to identify genes, transcripts and proteins which control the expression of relevant phenotypes. Applying this understanding to the barley genetic resources exclusive to SCRI will optimise identification of cultivars better able to cope with the future requirements of farmers.

Initial results have demonstrated that while the overriding driver of root proliferation by commercial varieties of barley is water availability there is an additive effect of P-availability. We now need to elucidate whether barley cultivars have genotypic variation in their response to combined water and nutrient limitation.

Variation in barley rhizosphere biochemistry, potential to improve mineral nutrition

Plant roots exude inorganic and organic compounds into the soil which alter their rhizosphere biochemistry. These compounds have an important effect on mobilisation and uptake of nutrients by plants and micro-organisms either by affecting pH or by acting on specific substrates to release otherwise unavailable elements.

Enzymes such as phosphatases release phosphate from organic sources (unavailable to plants) into plant available forms in soil solution. Phosphatases have been identified in the roots of a wide range of plants and have been shown to increase with P-deficiency.

We are screening the collection of barley cultivars unique to SCRI for natural variation in root exudates. This will potentially lead to identification of lines which are able to more efficiently capture resources under nutrient limited conditions. Using a hydroponic system and screening under phosphorous deficient conditions in the first instance, we have detected enhanced phosphatase activity in exudates of a Hebridean landrace barley variety when compared with the commonly grown cultivar 'Optic'. 

We have also detected significant differences in the activity of enzymes associated with organic matter degradation. This suggests that important natural variation can be found in traits which will help identify cultivars for more sustainable agricultural practices relying less on artificial inputs for sufficient crop yields.