Productivity of sunflower hybrids with erectoid leaves at various plant densities☆

We carried out the research in 2018–2019 in the Western Ciscaucasia on leached chernozem, low-humus, extra-heavy, heavy-loamy to study the possibility of cultivation of new sunflower genotypes with a compact habitus at a high plant density (80 000, 100 000 and 120 000 plants/ha) and a row width of 35 cm. We chose sunflower hybrids of the breeding of V.S. Pustovoit All-Russian Research Institute of Oil Crops with the normal (Triumph and Berkut) and the erectoid (Triumph er-2, Triumph Er-3, Berkut er-2, Berkut Er-3) leaf position as an object of research. The high lodging capacity of the erectoid hybrids Triumph еr-2 (30.2%) and Triumph Еr-3 (10.9%) suggests potential yield losses due to non-threshing of heads during the combine harvesting. The highest productivity and oil content of seeds of normal and erectoid hybrids was obtained at the plant density of 80 000 plants/ha. The densification of sowings to 100 000 and 120 000 plants/ha led to a decrease in the traits of yield structure and productivity. The limited resources of the environment do not allow achieving both high productivity and product quality in sowings with the plant density exceeding 80 000 plants/ha. The compact habitus of sunflower plants is not a determining factor in the development of productivity of sowings with a high plant density