Crop rotation options for dryland agriculture: An assessment of grain yield response in cool-season grain legumes and canola to variation in rainfall totals

Crop production in dryland systems is mainly dependent on water availability from rainfall which is highly variable between years and locations. We employed the widely used boundary-line analysis, with an existing industry dataset from across the Australian dryland cropping regions, to investigate the relative sensitivity of grain yield in canola (Brassica napus L.), chickpea (Cicer arietinum L.), faba bean (Vicia faba L.), field pea (Pisum sativum L.), lentil (Lens culinaris L.), and narrow-leafed lupin (Lupinus angustifolius L.) to variation in rainfall totals. Chickpea had the lowest non-productive water use, was more responsive to water supply, and reached its maximum yield at a lower water supply than the other species. In contrast canola had the highest non-productive water use, was less responsive to water supply, and reached its maximum yield at a higher water supply than the other species. These results suggest that chickpea offers the most stable outcome, and canola the greatest variation, in response to the variability in rainfall totals between years and locations. © 2019 Elsevier B.V

A reduced tillering trait shows small but important yield gains in dryland wheat production

Reducing the number of tillers per plant using a tiller inhibition (tin) gene has been considered as an important trait for wheat production in dryland environments. We used a spatial analysis approach with a daily time-step coupled radiation and transpiration efficiency model to simulate the impact of the reduced-tillering trait on wheat yield under different climate change scenarios across Australia's arable land. Our results show a small but consistent yield advantage of the reduced-tillering trait in the most water-limited environments both under current and likely future conditions. Our climate scenarios show that whilst elevated [CO2 ] (e[CO2 ]) alone might limit the area where the reduced-tillering trait is advantageous, the most likely climate scenario of e[CO2 ] combined with increased temperature and reduced rainfall consistently increased the area where restricted tillering has an advantage. Whilst long-term average yield advantages were small (ranged from 31 to 51 kg ha-1 yr-1 ), across large dryland areas the value is large (potential cost-benefits ranged from AUD 23 to 60 MIL yr-1 ). It seems therefore worthwhile to further explore this reduced-tillering trait in relation to a range of different environments and climates, because its benefits are likely to grow in future dry environments where wheat is grown around the world