Abstract:

Population of Heterodera glycines fluctuations in the fields during growth of soybean. In order to investigate dynamics of Heterodera glycines in soybean roots, and provide more information of effective control for soybean cyst nematode, distribution and dynamics of soybean cyst nematode (SCN, Heterodera glycines, race 4) in the soybean roots were monitored during the period of 7–37 d after seedling emergence in 2006 and 2007. The results indicated that distribution of SCN population closely related to the growth of roots. Nematodes invaded the roots at 7 days after seedling emergence, and nematode density and population increased with the growth of soybean roots, the fluctuation of nematodes per centimeter root showed a sigmoid curve. The changed of nematodes per cm root showed an inverse trend with the age of seedlings between taproot and lateral root. Nematode density in taproot had a declining trend, when that in lateral root increased to a stable value. Difference of nematode density between taproot and lateral root decreased with deepening the soil layer, number of nematodes per cm root and percent to total nematodes reached the ultimate number in the 5–15 cm soil, suggesting that most of the nematodes distributed in lateral root and at the 5–15 cm soil layer during the soybean seedling stage.

Key words: Soybean, Heterodera glycines, Root, Space-time dynamics