Sunflower remains the leading oilseed crop in Ukraine. Hybrid sunflower provides farmers with high profitability and the highest oil yield per hectare.
Sunflower yields are influenced by many factors, and one of the key ones is the right choice of hybrid. A hybrid that is suitable for the agroclimatic zone is the first step towards consistently high yields with high oil content and improved quality characteristics. When choosing a hybrid, it is important to take into account its adaptability, recommendations for growing in a particular zone, resistance to diseases, pests and abiotic stresses, as well as the basic requirements of the cultivation technology.
One of the important elements of the technology is the correct timing of sowing. Timely sowing allows us to maximise the potential of the hybrid, improve product quality, use mineral nutrition and protection products more efficiently, and optimise harvesting time, which generally helps to reduce costs and increase the profitability of sunflower cultivation.
Every year, the issue of sowing dates remains relevant and causes debate, as it depends on both weather conditions and farm capacities. However, even in a changing climate, high and stable yields can be obtained by sowing sunflower at the optimal or optimal late date.
Given the biological characteristics of the crop, sunflower sowing should begin when the soil temperature at the depth of seed placement reaches +10 °C and tends to rise. Compliance with the temperature regime directly affects the speed and friendliness of emergence, reduces the risk of soil diseases and pests (wireworms, false wireworms).
If sown too early, when the soil temperature is only +5…6 °C and does not rise, germination can be delayed by 3-4 weeks. This leads to sparse and weak seedlings with typical damage from soil pests. In such cases, farmers complain about the seeds without thinking about the impact of low temperatures and early spring frosts. At the same time, sowing too late can lead to a lack of moisture in the topsoil, especially in arid regions. Therefore, in cases of late spring, it is allowed to start sowing at a temperature of +8 °C, focusing on a stable positive warming trend.
To achieve maximum results, it is necessary to select the sowing dates that ensure the highest yields in the specific weather conditions of the farm. It is worth remembering that even the same hybrid sown at different times can show a yield difference of up to 30%. Therefore, the main criterion for choosing the sowing dates should be to achieve the maximum average yield.
In 2024, the Pole Znannia agricultural test site was used to study the impact of sowing dates on the yield, oil content and nature of Evrosem sunflower hybrids. The site is located in the village of Tsyhanske, Poltava region. Sunflower hybrids by Evrosem were sown in the experiment: Stark 7+ Sumo, Tor 7+ Sumo, Avalon 7+ and Groot.
Stark 7+ Sumo is a medium-early intensive sunflower hybrid with a high level of adaptability. It is grown using Express technology (Sumo, Granstar). It starts growing well at the beginning of the growing season. It has excellent drought tolerance, is resistant to all known races of broomrape (up to 7+ races). It has a wide window for sowing at different times. It is not affected by diseases: downy mildew, phomosis, rust, phomopsis. In commercial crops, it demonstrated the highest oil content among all Eurosem hybrids – 54.1%.
Avalon 7+ is a mid-season hybrid of the classical cultivation direction. In laboratory and field trials, it has shown high resistance to the most aggressive races of broomrape from all over Ukraine (A-G+). The sunflower is an extensive type, stable and plastic. Due to its high drought tolerance score, it is mainly grown in the southern and south-eastern parts of Ukraine. The average oil content is 48-50%.
Tor 7+ Sumo is a hybrid under Granstar with an ultra-short growing season of 90-95 days. This ultra-early hybrid has high initial growth energy and is resistant to downy mildew, broomrape races A-G+, and stem lodging. The average oil content is 50-52%.
Groot is a sunflower for Clearfield cultivation technology (under Euro-Lightning). It has the greatest potential among IMI hybrids. It is a medium-early hybrid with high drought resistance and tolerance to all races of downy mildew.
Experimental sowings were carried out in the following periods:
- I – 23 April
- II – 5 May
- III – 15 May
- IV – 23 May
- V – 10 June
These sowing dates for these hybrids have been tested for several years.
For the Tor 7+ hybrid, the best sowing date was 5 May, in which case its yield was 3.1 t/ha, with almost the highest oil content of 49.7% and weight in bulk of 389 g/l. Similarly, for the Grut hybrid, the best sowing date was 5 May, and when sown at this date, the yield was the highest – 3.88 t/ha, oil content – 49.9%, and weight – 403 g/l. These two hybrids have a rather short time period for sowing, so you need to do it right away and sow them in time.
In the Stark 7+ Sumo hybrid, the highest yields were recorded from 5 May to 23 May (an average of 3.44 to 3.66 t/ha was harvested during the test years). At the same time, the oil content was at a high level – more than 50%, as well as the weight – 438 g/l.
The Avalon 7+ sunflower hybrid has a much wider sowing range from 23 April to 23 May. That is, it is a great hybrid that allows you to prepare well for the sowing campaign, with Avalon yields starting at 3.6 t/ha.
Based on our results, we recommend sowing sunflower hybrids in this way in central Ukraine:
- Thor 7+ Sumo 5-15 May
- Stark 7+ Sumo 5-23 May
- Groot 5-15 May
- Avalon 7+ 23 April-15 May.
The right sowing date for the hybrid will ensure not only successful and even emergence of the crop, but also high test yields. Choose Evrosem seeds and sow according to our recommendations.