Yield structure and grain quality of newly developed rice lines (Oryza sativa L.)

Abstract

Purpose. Assessment of newly created rice lines by yield structure indicators and grain and groat quality in the conditions of the Southern Steppe. Materials and research methods. Breeding work with rice (Oryza sativa L.) at the Institute of Climate-Smart Agriculture of the NAAS is carried out according to the scheme of the breed- ing process using the genetic potential of variety samples of the world collection and varieties of cultivated rice of our own selection, which have a high diversity of traits and properties. The best of them, after careful study, are used in hybridization in order to obtain lines that combine all the necessary parameters of the variety model. The study was conducted during 2022–2024 at the Institute of Climate-Smart Agriculture of the NAAS in the crop rotation fields of the basic farm “Maiak” in Kiliia, Odesa region. Research results. To determine technological indicators (grain yield, whole kernel yield, vitreousness, cracking), a significant representative factor is the grain index (l/b – the ratio of the grain length to its width), which can significantly affect the quality of processing. Newly created rice lines are characterized by a complex of economically valuable traits that are realized to varying degrees, depending on the cultivation technology and weather and climatic conditions of the growing season. The grain index (l/b up to 2.5) of all newly created lines corresponded to the shortgrain type, except for lines O 54–23, which was of the long-grain type (l/b had more than 2.6). The yield structure indicators of the newly created lines had high variability. The average number of grains in the panicle ranged from 198 pcs. (in short-grain forms) to 310 pcs. (in long-grain forms). The largest number of grains in the panicle was distinguished by samples from short-grain forms – Line O 53–23 (220 pcs.), O 42–23 (225 pcs.), O 44–23 (230 pcs.), and long-grain forms – O 54–23 (310 pcs.). The length of the panicle ranged from 18.1 to 19.7 cm in short-grain samples, and in long-grain – 17.8 to 18.1 cm. The highest productivity of the main panicle was distinguished by sam- ples with short-grain type of grain O 53–23 (6.55 g.), O 42–23 (6.65 g.), O 44–23 (6.80 g.), and long-grain – line O 54–23 (8.31 g.). The virtuousness of the grain among the best short-grain forms is on average 98.8 %, and in longgrain forms 100 %. The following samples stood out with high virtuousness: Lines O 16–23, O 42–23, O 44–23, O 53–23 (100 %), which were on a par with the Viscount and Marshal standards – 100 %. According to our research, the total yield of cereals was on average 69.67, 68.69 %, and the best among the newly created lines were: O 42–23, O 44–23, O 53–23 (70.15–71.46 %). Conclusions. New high-yielding rice lines with high adaptability to the conditions of southern Ukraine have been created, namely: early-ripening lines – O 16–23, O 35–23, O 42–23, O 43–23; mid-ripening lines – O 44–23, O 50–23, O 53–23; long-grain line O 54–23. The grain yield of the newly cre- ated lines is 9.45–11.46 t/ha with high grain quality. The newly created lines exceed the grain yield standards by 0.66–2.86 t/ha (by 7.5–32.7 %) in the short-grain group and by 2.32 t/ha (by 28.1 %) among long-grain. The newly created lines are registered in the National Center for Plant Genetic Resources of Ukraine. The new lines are plastic to fluctuations in growing conditions, are characterized by high technological and economic characteristics, have high yield structure indicators and quality indicators, are capable of producing high yields.