Predecessors have a significant impact on the growth and development of the following crop. Depending on the predecessor crop there is different amount of nutrients, moisture left in the arable soil layer as well as phytosanitary conditions of fields differ. The research programme included the study of peculiarities of growth, development and yield formation of the new sunflower hybrids (LG59580, LG50609SX, PR64LE25, Suzuka), which belong to various ripeness groups, depending on predecessors in the north Steppe of Ukraine in order to improve major zonal energy-efficiency technology of sunflower cultivation. In terms of phytosanitary, cultivation of sunflower after sunflower had negative effect. During the cultivation the number of affected plants was twice fewer after other better predecessors. The Suzuka hybrid showed higher resistance. All of the hybrids formed higher productivity in case of their cultivation after winter wheat as a predecessor with 3.45–3.72 t ha-1 and after corn as their predecessor with 3.34–3.61 t ha-1. Sunflower re-seeding caused yield reduction by almost 1 t ha-1. The thousandkernel weight in all hybrids under research was higher in case of their cultivation after winter wheat as a predecessor. After winter wheat and grain corn this parameter fluctuated within the range of 71.5–74.5 and 69.3–72.5 g respectively, depending on the hybrid, while the parameter was much lower after sunflower and only reached 60 g in LG50609SX hybrids. The highest oil content in all the hybrids was measured after winter wheat and grain corn as predecessors. The highest oil content indications of 50.8–51.0% were defined in LG59580 and Suzuka hybrids. Thus, the cultivation of the hybrids under research after winter wheat and grain corn as predecessors contributed to the formation of healthy and productive plants, while growing sunflower in re-seeding conditions led to impaired phytosanitary conditions, reduced yield and decreased quality of seeds.
Andriienko et al. (Thu,) studied this question.