Donor-acceptor relationships as a criterion for selection of rice plants for productivity: assessment of the harvesting index of the main shoot

Relevance. The article presents the results of studying the production processes of rice agrophytocenoses in order to identify the morphophysiological characteristics of plants associated with the coefficient of economic efficiency of photosynthesis (or harvesting index HI) for improving the evaluation methods in breeding for yield.Methodology. In a vegetation experiment, photosynthetic and production activity was studied in 5 rice varieties on three backgrounds of mineral nutrition.Results. Varietal differences in yield on one background of mineral nutrition are not associated with the parameters of photosynthetic activity, but are determined by the nature of the distribution of assimilates formed during photosynthesis among plant organs. Their intensive influx into storage tissues to developing panicles and grain determines the increased productivity of the varieties Rapan 2, Nautilus and Yubileiny 85. The traits of varieties that determine the activity of the photosynthetic apparatus, the distribution of assimilates among plant organs, the size and structure of the biological and economic yield and donor-acceptor relations, which are the leading factor in the production process at the level of the whole plant and agrophytocenosis, have been identified. The harvesting index of the cenosis varied from 35.5 to 50.3% and of the main shoot from 34.7 to 52.1%, the yield varied from 0.652 to 1.124 kg/m2. A high genotypic relationship has been established between the harvesting index (HI) and the yield (0,90±0,25), the grain content of the agrophytocenosis (0,88±0,27) and the weight of grain per plant (0,99±0,03). A high genotypic relationship was established between the harvesting index (Khoz) and yield (0.90±0.25), grain content of the agrophytocenosis (0.88±0.27) and grain weight per plant (0.99±0.03) under optimal nutritional conditions.The analysis has shown similar relationships with the coefficient of economic efficiency of photosynthesis of the main shoot (HI of the main shoot), which allows it to be used for assessing productivity.