Examining the yield potential of barley near-isogenic lines using a genotype by environment by management analysis

Here we modelled the influence of phenology of barley crops under diverse environmental and management conditions. Such trait manipulation can assist breeders in genotype selection and growers in better managing barley crops to achieve their yield potential. We first developed two near isogenic lines (NILs) of barley (Eps-317-1-E, and Eps-317-1-L). NILs were developed from a cross between TX9425, a Chinese landrace, and Franklin, an Australian malting barley. Field experiments were then conducted in Tasmania, Australia, using three sowing dates per year during 2015, 2016 and 2017 to parameterise and test the barley module of the APSIM model (APSIM-Barley). We then conducted a genotype by environment by management (GxExM) analysis using ten sites across the Australian wheat-belt, with a range of sowing dates, fertiliser rates and planting densities. The early genotype (Eps-317-1-E) performed better in environments prone to terminal drought and heat stress effects. This was due to earlier flowering and a propensity for greater transpiration-use efficiency from growth stage (GS) 50 to 87. The late NIL (Eps-317-1-L) generally produced higher yield in long-season environments with high rainfall and cool terminal temperatures. Performance of all genotypes was generally better for May sowings (being mid-autumn in the southern hemisphere), wherein yields of the two NILs were highest. Overall, our study showed that Eps-317-1-E was more adapted to regions prone to drought and heat stress, while Eps-317-1-L was more suited to regions with longer growing seasons. This study exemplifies how models can be used in concert with breeding experiments and thus provides farmers and breeders with opportunities to examine how new genotypes will perform in diverse environments under multiple management conditions.