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Abstract Background Onion grass (Romulea rosea) is a common weed that infests native and improved pastures in the Mediterranean environments of southern Australia. It is a very challenging weed to control due to its distinctive growth and survival mechanisms involving corms. Methods Three glasshouse experiments were conducted in Australia to investigate the response of onion grass to defoliation and fertiliser application, the development and growth of onion grass corms and the chemical control of the weed in winter and spring. Results Defoliating consistently to 1 cm above ground reduced corm weight by 84% compared with the control. Medium or high fertiliser application did not increase herbage mass of onion grass compared with the nonfertilised treatment. The corm weight of onion grass declined from Weeks 1 to 8 after emergence, remained at 53–60 mg dry matter (DM) corm−1 from Weeks 8 to 19 and then declined on average to 37 mg DM corm−1 up to Week 26 after emergence. New corms started to develop at Week 6 after emergence. A small proportion of the onion grass plants (7.5%) developed multiple new corms (3–6 corms) from a single old corm. The most effective herbicide control was a winter application of metsulfuron methyl or imazamox as an alternative product to protect clover. Conclusions This study has identified the growth and development patterns of onion grass corms, how the plant responded to defoliation and fertiliser application and effective chemical control of this weed. These findings have significant practical implications for the improvement of onion grass‐infested pastures.

Previous studies have shown reduced enteric methane emissions (ME) and residual feed intake (RFI) through the application of genomic selection in ruminants. The objective of this study was to evaluate feeding behaviour traits as genetic indicators for ME and RFI in Australian Maternal Composite ewes using data from an automated feed intake facility. The feeding behaviour traits evaluated were the amount of time spent eating per day (eating time; ETD; min/day) and per visit (eating time per event; ETE; min/event), daily number of events (DNE), event feed intake (EFI; g/event) and eating rate (ER; g/min). Genotypes and phenotypes of 445 ewes at three different ages (post-weaning, hogget, and adult) were used to estimate the heritability of ME, RFI, and the feeding behaviour traits using univariate genomic best linear unbiased prediction models. Multivariate models were used to estimate the correlations between these traits and within each trait at different ages. The response to selection was evaluated for ME and RFI with direct selection models and indirect models with ETE as an indicator trait, as this behaviour trait was a promising indicator based on heritability and genetic correlations. Heritabilities were between 0.12 and 0.18 for ME and RFI, and between 0.29 and 0.47 for the eating behaviour traits. In our data, selecting for more efficient animals (low RFI) would lead to higher methane emissions per day and per kg of dry matter intake. Selecting for more ETE also improves feed efficiency but results in more methane per day and per kg dry matter intake. Based on our results, ETE could be evaluated as an indicator trait for ME and RFI under an index approach that allows simultaneous selection for improvement in emissions and feed efficiency. Selecting for ETE may have a tremendous impact on the industry, as it may be easier and cheaper to obtain than feed intake and ME data. As the data were collected using individual feeding units, the findings on this research should be validated under grazing conditions.