Relationship between leaf photosynthetic characteristics and yield in buckwheat

A field trial was conducted to assess the variation in leaf photosynthetic characteristics in 10 buckwheat (Fagopyrum esculentum and F. tatatricum) cultivars. Wide variability was observed for photosynthesis and related characters measured at flowering and seed filling stages. Photosynthetic rate (A) was positively and significantly associated with stomatal conductance (gs), transpiration rate (T) and total biomass (TDM). The specific leaf mass (SLM) exhibited a strong positive association with rate of photosynthesis and TDM. The positive association between SLM, photosynthetic rate and total biomass (TDM) suggests that SLM, an easy to measure character can be used in breeding programmes to select for higher photosynthetic rate and higher biomass. Specific leaf area (SLA) was negatively correlated with A/T ratio suggesting its utility for screening for high water use efficiency in buckwheat. The A/T ratio was positively and singificantly related to A/g_s and A/C₁ ratio. The strong association between A/T and A/C_i, A/g_s suggests that these ratios determine the potential water use efficiency of the leaf.