title: Robust phenotyping strategies for evaluation of stem non-structural carbohydrates (NSC) in rice.
abstract: Rice plants (Oryza sativa) accumulate excess photoassimilates in the form of non-structural carbohydrates (NSCs) in their stems prior to heading that can later be mobilized to supplement photosynthate production during grain-filling. Despite longstanding interest in stem NSC for rice improvement, the dynamics of NSC accumulation, remobilization, and re-accumulation that have genetic potential for optimization have not been systematically investigated. Here we conducted three pilot experiments to lay the groundwork for large-scale diversity studies on rice stem NSC. We assessed the relationship of stem NSC components with 21 agronomic traits in large-scale, tropical yield trials using 33 breeder-nominated lines, established an appropriate experimental design for future genetic studies using a Bayesian framework to sample sub-datasets from highly replicated greenhouse data using 36 genetically diverse genotypes, and used 434 phenotypically divergent rice stem samples to develop two partial least-squares (PLS) models using near-infrared (NIR) spectra for accurate, rapid prediction of rice stem starch, sucrose, and total non-structural carbohydrates. We find evidence that stem reserves are most critical for short-duration varieties and suggest that pre-heading stem NSC is worthy of further experimentation for breeding early maturing rice.
authors.affiliation: Section of Plant Breeding and Genetics, School of Integrated Plant Sciences, Cornell University, Ithaca, NY 14853-1901, USA.
authors.forename: Diane R
authors.initials: DR
authors.lastname: Wang
authors.affiliation: Integrated Biorefinery Research Facility, National Renewable Energy Lab, Golden, CO 80401, USA.
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Wolfrum
authors.affiliation: International Center for Tropical Agriculture, Km17 Recta Cali-Palmira, PO Box 6713, Cali, Colombia.
authors.forename: Parminder
authors.initials: P
authors.lastname: Virk
authors.affiliation: International Rice Research Institute, Los Baños, Laguna, Philippines.
authors.forename: Abdelbagi
authors.initials: A
authors.lastname: Ismail
authors.affiliation: Bayesic Research, Ithaca, NY 14850, USA.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Greenberg
authors.affiliation: Section of Plant Breeding and Genetics, School of Integrated Plant Sciences, Cornell University, Ithaca, NY 14853-1901, USA srm4@cornell.edu.
authors.forename: Susan R
authors.initials: SR
authors.lastname: McCouch
mesh_terms: D002241:Carbohydrates / Q000032:analysis / Q000502:physiology*; D014644:Genetic Variation; D012275:Oryza / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D000069600:Plant Breeding; D018547:Plant Stems / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D019655:Quantitative Trait, Heritable; D019265:Spectroscopy, Near-Infrared; D013213:Starch / Q000032:analysis; D013395:Sucrose / Q000032:analysis
chemical_list: D002241:Carbohydrates; D013395:Sucrose; D013213:Starch
keywords: 
  Oryza sativa
  ; Near-infrared spectroscopy; non-structural carbohydrates; partial least-squares; replication; yield potential.