Relationship between yield, carbon isotope discrimination and stem carbohydrate concentration in spring wheat grown in Ningxia Irrigation Region (North-west China)

Abstract

Carbon isotope discrimination (Δ) in flag leaf, grain and basal stem, grain yield (GY), and harvest index (HI), were determined in a collection of 20 bread wheat cultivars (landraces, released cultivars and advanced lines) in Yinchuan, located in the central region of the Ningxia region (North-west of China), in 2007 and 2008. In 2008, specific stem DW (SSDW) and carbohydrates, including water-soluble carbohydrate (WSC), non-water-soluble carbohydrates (NWSC) and total non-structural carbohydrate (TNSC) in stem were also measured. Relationships between GY, HI, SSDW, accumulation and mobilisation of stem carbohydrates and Δ were analysed. There were positive and significant correlations between grain Δ, basal stem Δ and GY in 2007 and 2008. A significant and positive correlation between Δ and HI was found. In 2008, positive correlations were recorded between stem WSC concentration, SSDW sampled 7 days after anthesis and Δ. Carbon isotope discrimination was associated positively with remobilisation efficiency of stem WSC and TNSC. While negative relationships were noted between Δ and SSDW at maturity, stronger association was noted between Δ, carbohydrate concentration, accumulation and mobilisation efficiencies on stem length basis than on stem DW basis. In conclusion, there is a good relationship between Δ and carbohydrate in stem of wheat when irrigation does not meet the crop’s water requirement and wheat experiences a slight water stress after anthesis.