Development of a novel semi-hydroponic phenotyping system for studying root architecture.

A semi-hydroponic bin system was developed to provide an efficient phenotyping platform for studying root architecture. The system was designed to accommodate a large number of plants in a small area for screening genotypes. It was constructed using inexpensive and easily obtained materials: 240L plastic mobile bins, clear acrylic panels covered with black calico cloth and a controlled watering system. A screening experiment for root traits of 20 wild genotypes of narrow-leafed lupin (Lupinus angustifolius L.) evaluated the reliability and efficiency of the system. Root architecture, root elongation rate and branching patterns were monitored for 6 weeks. Significant differences in both architectural and morphological traits were observed among tested genotypes, particularly for total root length, branch number, specific root length and branch density. Results demonstrated that the bin system was efficient in screening root traits in narrow-leafed lupin, allowing for rapid measurement of two-dimensional root architecture over time with minimal disturbance to plant growth and without destructive root sampling. The system permits mapping and digital measurement of dynamic growth of taproot and lateral roots. This phenotyping platform is a desirable tool for examining root architecture of deep root systems and large sets of plants in a relatively small space.