Evaluation of stem non-structural carbohydrates (NSCs) in cultivated Asian rice, Oryza sativa

Rice has been observed to accumulate non-structural carbohydrates (NSCs) primarily in the form of sucrose and starch, in its stems prior to flowering. These pre-anthesis reserves are subsequently remobilized from the stem to the grain and are considered an important source of carbon assimilates during grain-filling, supplementing concurrent photosynthesis. Adequate accumulation and sufficient remobilization of stem NSC are of interest to the breeding community in the context of yield stability in variable environments, as they have been shown to be important contributors to grain-filling under sub-optimal climatic conditions (e.g. water stress). Because NSC storage and remobilization reflect dynamic source-sink relationships in the plant and are strongly affected by environmental factors (GxE), relatively little work has been done to identify genetic associations with these traits.

We have measured starch and sugar levels in the stems of a small diversity panel using a large number of replicates of indica and tropical japonica genotypes under greenhouse conditions at flowering and maturity as a pilot assessment of the levels of variation in stem carbohydrates levels.