Dill Seed Trials at CSIDC

Introduction

Dill is well known as a garden herb used primarily in home pickling. Aromatic (essential) oil extracted from either the whole plant or from the seed is used for commercial pickling. Dill is used as flavoring in cheese, potato, and pasta products.

The dill seed normally contains between 2 and 4% essential oil. The component of greatest interest is a phenolic compound called carvone. The essential oil must have a carvone content of at least 30% to be commercially acceptable.

Irrigated dill research was started in 1994 with a study conducted by Dr. F. Sosulski, of the Department of Plant Sciences, University of Saskatchewan, Dr. A. Slinkard of the Crop Development Centre, and Dr. J. Wahab of the Canada-Saskatchewan Irrigation Diversification Centre. A summary of the on-going work is presented here.

Dill Yield Trials

A seed yield trial comparing six varieties of dill was grown under irrigation at CSIDC in 1994 and 1995. The varieties Leaf and Dill R produced the highest yields. Low yields in 1994 were due to high shattering losses during a severe windstorm (Table 1).

Effect of Seeding Date

The variety Bouquet was seeded on four dates in 1995. The seed yield, essential oil yield, and total extractable oil yield were greatest at the May 18 seeding date (Table 2).

The highest essential oil contents (3.6%) were obtained at the May 4 and May 12 seeding dates. The essential oil contents of seed from the later seeding dates were slightly lower. The carvone content was increased with delayed seeding. The total oil content was similar for the first two dates and increased slightly at the later seeding dates.

Oil Content and Quality

The oil content and oil quality of dill seed grown at CSIDC are summarized in Table 3. The essential oil content, though lower in 1995 than in 1994, was within the desired level (2-4%) for each year. The carvone content of the oil was higher in 1995 than 1994, but was at acceptable levels in both years. The content of total extractable oil in the seed was similar for both years.