Higher yielding varieties of common buckwheat (Fagopyrum esculentum Moench) with determinate growth habit (single mutation det) manifest higher photosynthesis rate at stage of grain filling

Abstract

Comparison of common buckwheat varieties with determinate vs. indeterminate growth habit reveals no differences in leaf photosynthesis rate at stage before flowering. However, at stage of seed filling the difference was significant. Maximal difference was 20 days after early flowering, i.e in period of most intensive seed formation. These results show that determinate varieties have higher sink strength providing by developing seeds. It is correlated with higher yield ability of such varieties. Probably, growth limitation resulting from det-mutation leads to some shifts in system of sink priorities of buckwheat plant and allows initiate the development of additional seeds. One more possible cause of alteration of the physiological parameters in determinate varieties is some optimization of plant structure: in terms of physiology the determinate buckwheat is a plant which is more similar to cereals than indeterminate buckwheat. However, underlying physiological changes accompanying the transition from indeterminate toward determinate growth in buckwheat remain almost unknown. Assumption about strong effect of det-mutation per se on photosynthesis rate was not supported in our work. Alternative assumption about accumulation of additional genes enhancing the sink ability suggests opportunities for additional progress in the selection work using tools evaluating photosynthesis intensity at stage of grain filling.