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Water use in both urban and rural communities has become an enormous environmental and social issue, and over 30% of domestic water consumption is applied outdoors. To use Australia's unique biodiversity to select turfgrasses that maintain quality with reduced inputs of water and nutrients, we have collected about 500 indigenous couch grass genotypes and have begun to characterise them using physiological and genomics tools. Here we report on experiments that aim to develop the methodologies for screening a large number of genotypes for water use efficiency. Eight Cynodon grasses were grown in 40-cm-long PVC tubes with two soil types, two cutting heights, and four replications. The plants were grown at field capacity for several weeks prior to applying a terminal water stress. A survival period was estimated based on the time from the last watering to the time that all green leaf was lost. Large genotypic differences in survival period of up to 14 days were observed. Two genotypes, '81-1' and 'CT2', outperformed the other genotypes for survival period, possibly due to lower rates of evapotranspiration either through lower stomatal conductance and/or lower leaf area.

Increasing demand for scarce water resources in Australia has led to the selection of turfgrass genotypes with good drought tolerance. Here we describe the development of methodologies for screening green couch grasses (Cynodon spp.) grown in 40-cm PVC pots placed under rainout shelters. The drought tolerance of up to 8 genotypes including 4 commercial varieties (CT2, Grand Prix, Legend, and Winter Green) and 4 wild Australian ecotypes (1-1, 25-a-1, 40-1, and 81-1) was examined in 3 experiments conducted in 2007–08 and 2008–09. In the first experiment, all genotypes were grown with 2 soil types (clay and sandy soils) and 2 clipping heights (5 and 2 cm). Genotypic variation for survival period (defined as the period from the time water was withheld until 100% leaf firing had occurred) was high for the sandy soil × 2 cm clipping height treatment and, because retrieval of roots was easy, this combination was used in Expts 2 and 3 as the best system for screening drought tolerance. This method gave highly repeatable results across 2 years. Wild ecotype 81-1 had a significantly longer survival period than other genotypes, possibly associated with lower stomatal conductance early after water deficit was imposed, a greater root biomass at depth, and greater osmotic adjustment.