Genotypic differences in early wheat seedling establishment in natural soil investigated using non-invasive 3D magnetic resonance imaging

Seed germination and seedling establishment are the first important steps in a plant's growth cycle. We developed a measurement pipeline to quantify the early stages of root development in young seedlings in natural soil. We used non-invasive magnetic resonance imaging (MRI), providing us with 3D information about root structures. By growing up to 18 seedlings per pot (Ø=12.5cm, 10cm height) and by focusing on early growth (up to 4 days after start of germination), a much higher plant throughput compared to traditional 3D root measurement protocols in soil was achieved. Due to the high temporal resolution of the acquired data sets (4 images per day), dynamic traits such as shoot and root emergence time were obtained accurately. We used this 'deep phenotyping' approach, with multiple temporal and spatial layers of data, to investigate genotypic differences using the 8 parent lines of the NIAB MAGIC population. Clear genotypic differences in structural (e.g. root angle, root lengths, and number) and temporal (e.g. time of root emergence, shoot emergence) were quantified. We identified different growth strategies among the parent genotypes by correlating the temporal development of traits. This new MRI method offers a promising tool for high throughput root seedling screening in natural soil environments, along with opportunities to discover new traits based on dynamics of root and shoot development. This work was financially supported by BASF