Peculiarities of vegetative development of common buckwheat in different environments: some additional evidences with Chinese and Russian varieties

An aim of buckwheat breeding is to achieve an optimal morphological structure in terms of numbers of vegetative nodes on both main stem and two upper branches which are correlated with the duration of the varieties’ vegetation period. Within the species, there is a wide polymorphism for these characters, and the level of the polymorphism within one set of varieties can depend on the growing conditions. We analyzed the response of varieties from the Oryol region (central Russia) and Jilin province (northern China) to different growing conditions. Chinese varieties 'Baiqiao 1' and 'Baiqiao 2' showed weak and ambiguous response to growing conditions changes; 'Baiqiao 3' (China), 'Devyatka', 'Demetra' and 'Bogatyr' (Russia), showed a clear tendency for the formation of more vegetative nodes on main stem in Baicheng (Jilin), i.e. on a shorter day and higher temperature. All cultivars tend to have a reduced number of vegetative nodes on the upper branches in Baicheng compared to Orel. Some of these results differ from ones of previous studies that analyzed a set of buckwheat cultivars under different photoperiodic conditions. It may be explained by additional differences in environmental conditions, other than photoperiod. Differencin the variety sets also appear to be important.