Shovelomics: high throughput phenotyping of maize (Zea mays L.) root architecture in the field

Abstract

We present a method to visually score 10 root architectural traits of the root crown of an adult maize plant in the field in a few minutes. Phenotypic profiling of three recombinant inbred line (RIL) populations of maize (Zea mays L.; B73xMo17, Oh43xW64a, Ny821xH99) was conducted in 2008 in a silt loam soil in Pennsylvania and in a sandy soil in Wisconsin, and again in 2009 in Pennsylvania. Numbers, angles and branching pattern of crown and brace roots were assessed visually at flowering. Depending on the soil type in which plants were grown, sample processing took from three (sand) to 8 min (silt-loam). Visual measurement of the root crown required 2 min per sample irrespective of the environment. Visual scoring of root crowns gave a reliable estimation of values for root architectural traits as indicated by high correlations between measured and visually scored trait values for numbers (r 2 =0.46-0.97), angles (r 2 =0.66-0.76), and branching (r 2 =0.54-0.88) of brace and crown roots. Based on the visual evaluation of root crown traits it was possible to discriminate between populations. RILs derived from the cross NY821 x H99 generally had the greatest number of roots, the highest branching density and the most shallow root angles, while inbred lines from the cross between OH43 x W64a generally had the steepest root angles. The ranking of genotypes remained the same across environments, emphasizing the suitability of the method to evaluate genotypes across environments. Scoring of brace roots was better correlated with the actual measurements compared to crown roots. The visual evaluation of root architecture will be a valuable tool in tailoring crop root systems to specific environments.

Root Phenes for Enhanced Soil Exploration and Phosphorus Acquisition: Tools for Future Crops

“…More complex traits expressed later in plant development such as adventitious root formation are amenable to markerassisted selection using QTL or other molecular markers, although these tools have limited availability in many developing countries, where the need for phosphorus-efficient genotypes is greatest. A number of important root architectural phenes can be rapidly phenotyped in the field using a simple manual method called shovelomics, in which root crowns are excavated and visually scored for several root phenes at a rate of 2 min/plot (Trachsel et al, 2010).…”

Accelerating genetic gains in legumes for the development of prosperous smallholder agriculture: integrating genomics, phenotyping, systems modelling and agronomy

“…• Involves manual excavation of plants and separating roots from shoots • Washed roots are then placed on a phenotyping board for root trait quantification • New algorithms allow extraction of several root traits in a high throughput manner Trachsel et al (2011), Bucksch et al (2014) Accelerating genetic gains in legumes | 3297 Phenotyping platform (and institute or company)…”

Root system architecture: insights fromArabidopsisand cereal crops

“…VISUALIZING COMPLEX ROOT SYSTEM ARCHITECTURE The study of root architecture has always been compromised by the inherent difficulties in studying a system that necessarily operates in a below-ground environment. Extracting an entire root system from soil, while maintaining completeness and avoiding damage to the finer elements of the root system, is a challenge (though some results have been generated this way, for example via 'shovelomics', a method of excavating, washing and phenotyping crown roots [13,130]). …”