Shuhua Yang, Shengwei Du
（Henan Agricultural University）
Abstract：
This study investigates the impact of light and heat resources during the grain filling period on the grain filling of oil sunflower, and clarifies the utilization efficiency of light and heat resources under different sowing periods. Using a randomized block experimental design, with Xinkui 10 as the test material, three treatments were set up: spring sowing and two periods of re sowing. By comparing the changes in dry matter accumulation and moisture content of oil sunflower shells and seeds under different treatment conditions, the effects of meteorological conditions such as light and heat resources on the filling of oil sunflower lean fruit seeds during the filling period were studied, and the mechanism of oil sunflower yield formation was explored. Research has found that: (1) During the filling period, the total accumulated temperature, total solar radiation, and photosynthetically active radiation of oil sunflower treated with one stage of re sowing decreased by 21.95%, 32.43%, and 32.24%, respectively, compared to the spring sowing treatment. The grain yield did not change significantly, indicating that oil sunflower has good tolerance to low temperatures. (2) The yield of the second stage of re sowing treatment was 19.8% and 20.65% lower than that of the spring sowing and first stage of re sowing treatment, respectively. This indicates that as the sowing date is delayed, the temperature drop has a significant impact on grain filling, which can easily lead to a reduction in oil sunflower yield. (3) The impact of solar thermal resources on grain filling is mainly reflected in the accumulation rate of dry matter and moisture content. Spring sowing treatment of oil sunflower leads to a decrease in fresh weight of seeds due to rapid dehydration caused by high temperature in the later stage of grain filling; In the last week of maturity, the daily increase in dry matter and the dry matter weight of the skin during the second phase of re broadcasting showed a decreasing trend, and the dehydration of the skin was slow; The dry matter accumulation rate of seed kernels in the first stage of replanting oil sunflower was significantly higher than the other two treatments within 12-26 days after flowering, and the yield was also higher than the other two treatments. The light and heat conditions during the grain filling stage play an important role in the formation of oil sunflower yield. Even under conditions of insufficient light and heat resources, replanting oil sunflower can still achieve high yield. However, late sowing has a significant impact on grain filling, reducing yield, and is also not conducive to grain dehydration. The above research results are of great significance for determining the suitable sowing date for replanting oil sunflower, avoiding high temperature during peak flowering period, early frost stress in autumn, and improving grain plumpness. At the same time, they can also provide cultivation basis for the sustained high yield of oil sunflower after wheat replanting.
Key Words：
oil sunflower; accumulated temperature; photosynthetically active radiation; total solar radiation; grouting
