Canola response to plant density at Wubin 2013 trial report

Results

Established plant density

The established plant densities were nearly 37% of the targeted plant densities. No significant difference (p>0.05) between varieties for plant establishment were observed (Figure 1).

Figure 1 Observed plant density of canola varieties against target plant density at Katanning in 2013

Grain yield and gross margins

All varieties responded to increasing the plant density. However the response started to flatten at about 30 plants/m² for open-pollinated varieties GT Viper and ATR Stingray and at about 20 plants/m² for hybrids Hyola 404RR and Hyola 450TT (Figure 2). The economic optimum plant density for GT Viper and ATR Stingray was 39 plants/m² and 21 and 24 plants/m², respectively, for the hybrid type Hyola 404RR and Hyola 450TT varieties.

Figure 2a Grain yields of GT Viper at different crop densities at Katanning in 2013. Symbols are actual treatment means for grain yield and density and lines are fitted response curves.

Figure 2b Grain yields of Hyola 404RR at different crop densities at Katanning in 2013. Symbols are actual treatment means for grain yield and density and lines are fitted response curves.

Figure 2c Grain yields of Hyola450TT at different crop densities at Katanning in 2013. Symbols are actual treatment means for grain yield and density and lines are fitted response curves.

Hyola 404RR was the highset yielding variety (2394 kg/ha) and produced highest gross margins of $934/ha (Figure 3). Averaged over the densities, the gross margins of other varieties varied from $664-$781/ha.

Figure 3 Gross margins of open-pollinated and hybrid canola varieties in RR and TT herbicide regimes as impacted by plant density at Katanning in 2013

Rye grass

Rye grass head numbers were significantly higher (p<0.05) in TT treatments than in RR. There was much less ryegrass in RR treatments especially in Hyola 404RR at low densities. The ryegrass head numbers decreased rapidly as crop density increased (Figure 4).

Figure 4 Ryegrass head numbers in open-pollinated and hybrid canola varieties in RR and TT herbicide regimes as impacted by plant density at Katanning in 2013

Trial number: (13WH12)