Growth, yield and chemical composition of sunflower seeds in soil infested with different population densities of root-knot nematode

Abstract

The effect of the root-knot nematode, Meloidogyne incognita, on the growth and yield of sunflower grown in two different geographical regions was investigated in microplots at initial population densities of 0, 10, 100, 1000, 10000 and 20000 eggs and juveniles/kg soil. Tolerance limits of sunflower growth and yield, as well as the chemical composition of sunflower seeds, including oil, protein, carbohydrate, phenolic compound contents and fatty acids composition, were estimated. Tolerance limits (T) for fresh shoot and seed weights were 110 and 400 eggs and juveniles of M. incognita/kg soil, respectively, at Kafr-Kandeel region, and 105 and 153 eggs and juveniles/kg soil, respectively, at Kafr-Elsheikh region. Seed oil content (seed quality) and protein content in oil cakes (meal) were decreased by nematode infection, and the reduction was greater with increasing nematode inoculum. The fatty acids (oil quality) were not affected by nematode infection.