During the year 1951-52 in Paine Experiment Station of the Ministry of Agriculture, a field trial was conducted to know the influence of the seed size and the depth of seeding on seed yield in sunflower crop.
Certified Klein seed was used in this work.
Data was taken about: germination, vigor, height, diameter of heads and seed yield of plants from seeds of different sizes and seeded at four depths.
Results showed that:
Seed sizes did not affect the germination. Bigger seeds gave plants with higher vigor in the first development stages; but this difference disappeared afterwards and there was no difference in seed yield.
Depth of seeding influenced strongly the emergence, and a very different "stand" was obtained. The "stand" affected the vigor, height, diameter of heads and seed characteristics.
Seen yield was reduced seriously only at the maximum depth of seeding. Nevertheless in seeding depth near 13 centimeters, in which seed yield was not low, seeds obtained did not have good oil characteristics.
Six centimeters depth was determined the best for average conditions in Chilean Central region.
It was definite that small seeds have the same yield capacity than the large one.
There is a greater number of kernels per kilo with small grains and this may be an advantage in the south part of Chile where grains drills are proposed to be used with early sunflower varieties.

1 Extracto de la Tesis presentada para optar al Titulo de Ingeniero Agronómo de la Universidad de Chile