Yield structure of crambe (Crambe abyssinica Hochst.) under the effect of seeding rate and varietal characteristics

Abstract

Purpose. To establish an optimal seeding rate for different varieties of crambe (Crambe abyssinica Hochst) based on its influence on the formation of the main elements of the yield structure in the conditions of the Right Bank Forest Steppe.
 Methods. Crambe varieties ‘Belenzian’ (USA) and ‘CRA 5/79’ (Germany) were studied in field conditions (Cherkasy region) in the years 2020–2022. The crop was sown at the beginning of May in a continuous row method at seeding rates from 1.0 to 3.5 m seeds per hectare to a depth of 3–5 cm. Before harvesting, the preservation and biometric indicators of the plants were recorded, after which the seed yield was determined. The harvest was harvested by the direct harvesting method at a seed moisture content of 15%.
 Results. Regardless of the seeding rate, the preservation of plants before harvesting (on average according to the experiment) was somewhat higher in the variety ‘Belenzian’ – 72.8 against 70.4% in ‘CRA 5/79’. The lowest indicators in both varieties (64.1–67.6%) were recorded for the lowest sowing rate (1.0 and 1.5 m seeds/ha) and the highest (74.3–78.1%) for the highest seeding rate (3.0 and 3.5 m seeds/ha); the height of the plants was 73–90 cm on average, reaching a maximum in both varieties at seed rates of 2.0 and 2.5 m seeds/ha. An increase in the seeding rate to 3.0–3.5 m seeds/ha led to a significant decrease in plant height. The longest pods (4.7 and 4.5 cm) in variety ‘Belenzian’ were noted for the seeding rate of 1.0 and 1.5 m seeds/ha, while in variety ‘CRA 5/79’, the longest pods (3.3 and 3.5 cm) were obtained for the seeding rate of 2.0 and 2.5 m seeds/ha, respectively. The highest number of pods (144 and 146 in ‘Belenzian’; 130 and 135 in ‘CRA 5/79’), the weight of seeds from one plant (8.51 and 878 g and 8.04 and 8.23 g respectively) and the weight of 1000 seeds (8.78 and 9.00 g and 7.89 and 8.01 g, respectively) were obtained for seeding rate of 2.0 and 2.5 million seeds/ha. At the same seeding rates, the highest seed yield of ‘Belenzian’ was obtained – 2.12 and 2.23 t/ha, respectively, while in ‘CRA 5/79’ 2.04 and 2.00 t/ha of seeds was obtained at the seeding rate of 2.5 and 3.0 m seeds/ha, respectively.
 Conclusions. Seeding rate has a significant impact on the formation of biometric indicators that are the elements of the yield structure and, ultimately, the yield of crambe seeds. The values of most indicators increase with an increase in the seeding rate, reaching a maximum at 2.5 m seeds/ha, and then gradually decreasing. The optimal seeding rate from the point of view of the formation of a high yield of seeds in both crambe varieties is 2.5 m seeds/ha. The research results can be used to improve the elements of cultivation technology for growing crambe in the Right Bank Forest Steppe of Ukraine.