INTERRELATION BETWEEN STRUCTURAL YIELD ELEMENTS AND TECHNOLOGICAL INDICATORS OF WHOLEGRAIN AND MILLED RICE IN NEW RICE CULTIVARS

Abstract

Background. To obtain sustainable and high rice yields, it is crucial to select the best cultivars adapted to the cultivation in the main rice-growing areas. Combining high yields and technological quality indicators of wholegrain and milled rice is of vital importance. The practical solution of such an important task largely depends on successful breeding work. Materials and methods. Eight rice cultivars were evaluated in competitive trials in 2016–2018. Experimental plots were arranged within the rice irrigation system of the All-Russian Rice Research Institute in Belozerny Settlement, Krasnodar Territory. During the growing season, the following traits were visually evaluated: plant density, resistance to lodging, disease and pest infestation, and uniformity of crops. Screening and discarding operations on the plots planned for harvesting were followed by making model sheaves of 10–15 plants each for biometric analysis. Technological characteristics of wholegrain and milled rice were measured according to GOST 10843-76 and GOST 10987-76 standards. The results were mathematically processed and proved reliable. Results. Four promising cultivars ‘VNIIR 10244’, ‘VNIIR 10275’, ‘VNIIR 10279’ and ‘VNIIR 10282’ with a set of economically useful traits significantly exceeding the standard reference (st) ‘Flagman’ were selected. Their yield was 9.0 t/ha; 1000 grain weight: 29.3; 28.1; 30.4 and 26.3 g; hull percentage: 17.7; 19.7; 19.5 and 21.4%; and wholegrain content: 88.5; 93.5; 89.4 and 97.8%, respectively. Significantly high yields of these cultivars are due to the optimal number of fertile spikelets (150–160 pcs), panicle density (9.8–12.6 pcs/cm), and significant weight of grain from the main panicle (3.7–4.4 g), with an average sterility of 14.2–20.3%. A close positive correlation of yield traits with wholegrain content was observed in cvs. ‘VNIIR 10282’, ‘VNIIR 10279’, ‘VNIIR 10276’ and ‘VNIIR 10275’ (r = 0.92– 0.98). An inverse relationship between yield and kernel fissuring was observed in most genotypes, which testifies to the potential possibility of increasing their yield without the risk of reducing milled rice yield or wholegrain content. Conclusion. The evaluation resulted in identifying four promising rice cultivars: ‘VNIIR 10244’ and ‘VNIIR 10279’ (large-grain), ‘VNIIR 10275’ and ‘VNIIR 10282’ (medium-sized grain). They significantly exceeded the standard reference ‘Flagman’ in a set of economically useful traits: yield and its structural elements as well as technological characters of wholegrain and milled rice quality. The best of the selected genotypes according to the optimal ratio of the studied traits will be submitted to the State Variety Trials in 2019–2020.