Multipronged Phenotyping Approaches to Characterize Sugarcane Root Systems

Roots are the primary conductors of water and nutrients and play a vital role in sustaining growth and yield under stressful environments. The study of plant roots poses methodological difficulties in in situ assessment and sampling, which is especially true for sugarcane (Saccharum spp.). Traditional methods during the 1920s documented the genotypic variation in sugarcane root systems, after which few studies were reported on sugarcane root traits per se until recently. In addition to morphology, rhizosphere characteristics, including allelopathic effects and/or affinity for microbial symbiosis, determine plant establishment and survival. Ultimately, root systems define the above-ground productivity of sugarcane. With the impetus for climate-resilient varieties, it is becoming more relevant to explore and utilize the variability in root system traits of sugarcane. This paper describes multipronged approaches for sugarcane root phenotyping, including field excavation by trench sampling, the use of a root core sampler, raised platforms for root sampling, and raising plants under hydroponic culture, employed by a team of scientists at the Indian Council of Agricultural Research-Sugarcane Breeding Institute (ICAR-SBI). Field excavation by trench sampling is imperative to assess the plant roots in their natural growing environment. The use of raised platforms simulating field conditions and a root core sampler are alternative approaches, with a considerable reduction in time, uniform sample size, and less loss of root material. Hydroponic plant culture allows the study of morphology, anatomical features, and rhizosphere biology, including the exudation of organic compounds and microbial interactions. Data generated from different experiments using diverse sampling methods add to the wealth of information on the root system traits of sugarcane.