Photosynthetic capacity and net photosynthetic productivity of buckwheat varieties representing different periods of breeding

The studies were conducted according to the plan the CСU of Orel State Agrarian University "Plant genetic resources and their use" together with the breeders of All-Russian Research Institute of Grain Legumes and Groats Crops. The main objects of the research were 11 accessions of buckwheat representing different periods of breeding development: local populations, the old varieties which were bred in 1930-1960 and modern varieties bred in 1990-2010. Experimental material was grown in the field experiment. Drill seeding was carried out using the drill machine SKS-6-10 with a seeding rate of 3 million seeds per ha. A plot area was 10 m2, plot placement was random with four-fold replication. Care of sowing and harvesting were carried out in accordance with the methodological recommendations for the region. It is established that modern varieties in comparison with the predecessors form more powerful (13.3%, on average) photosynthetic capacity (PC), mainly due to the formation of larger leaves (12.3% on average) but not due to prolonging their functioning, which is one of the most important factors increasing their seed productivity. PC in years of research of local, old and modern varieties was on average 10.65, with 11.96 and 12.81 dm2/plant.×day respectively. Varietal differences significantly appear in the PC from the phase of "early flowering + 10 days" and continue until harvest, whereas net productivity of leaf photosynthesis as a result of selection does not change significantly. Its value largely depends on weather conditions, than by their hereditary characteristics. The net productivity of photosynthesis during the years of research of local, old and modern varieties was at an average of 9.0, 8.0 and 9.7 g/m2/plant×day, respectively. The highest photosynthetic activity of the leaves is seen in varieties of buckwheat in the period of vegetative growth and in phase of "early flowering + 30 days".