Coriander Trials at CSIDC

Introduction

Coriander is an annual herb widely adapted to a variety of climates and soil types. It is best adapted to well drained, non-saline loamy soils of moderate to high fertility. Acreage in Saskatchewan has increased in recent years. Estimates of 1996 production range as high as 14,000 acres.

Fresh coriander leaf, or cilantro, is used as a herb in East Indian, Mexican, and Chinese cooking. The crop is more commonly harvested for the spicy, aromatic seeds which are ground as an ingredient of spice mixtures, or are steam distilled to extract an aromatic "essential" oil. The oil is used in prepared or processed foods and toiletries.

High quality coriander seed has an essential oil content between 0.4 and 1.4 percent. The finest quality oils contain 60 to 70% linalool, a compound which produces much of the characteristic coriander flavor. The coriander seed contains an extractable vegetable oil fraction which may be blended with the essential oil (to form an oleoresin) for use in food and other non-food products.

The Canada-Saskatchewan Irrigation Diversification Centre began evaluating coriander in 1988. Research on irrigated spice crops was expanded in 1994 with a study conducted by Dr. F. Sosulski of the Dept. of Plant Sciences, University of Saskatchewan, Dr. A. Slinkard of the Crop Development Centre, and Dr. J. Wahab of the Saskatchewan Irrigation Diversification Centre. A summary of the on-going work on coriander is presented here.

Variety Evaluation

There are two types of coriander: large seeded, and small seeded. Large seeded varieties such as Autumn and Suzanne are currently grown in Saskatchewan.

Coriander yield trials were conducted under irrigation at CSIDC in 1990, 1994, 1995, and 1996. An overall summary of yields are presented in Table 1. A large seeded line from North Dakota, ND-1, produced consistent high yields.

Average plot yield of Autumn = 1986 kg/ha

Oil Content and Quality

A summary of oil yield and quality parameters for coriander grown at CSIDC from 1994 to 1996 is shown in Table 2. The essential oil content and percentage of linalool for coriander grown under irrigation at Outlook meets industry standards.

The large seeded coriander has a lower essential oil and linalool content than the small seeded types. The essential oil content of the small seeded types was sufficient to offset the lower seed yield, resulting in comparable oil yields.

Date of Seeding

The variety Chinese was sown at four dates in 1995. Seed yield, seed size, essential oil yield, and linalool content were highest for the May 4 seeding date (Table 3).

Late May seeding produced seed with a greater essential oil content, but lower seed yields resulted in reduced oil production.

Depth of Seeding

Three varieties of large seeded coriander were seeded at 3, 4, 5, and 6 cm depth. The highest average seed yield and greatest essential oil yield were obtained at the 6 cm seeding depth (Table 4). There were no significant differences in seed size, percent essential oil, or linalool content of the oil for the various seeding depths.

Seeding Whole Versus Split Fruits

The fruit of the coriander plant consists of two joined hemispheric seeds. The crop may be sown using either whole fruits or single seeds. In 1994, a yield benefit to using split seed over whole fruits was observed for the variety Autumn. In both 1995 and 1996, seed type had no effect on yield or oil content and quality for four large-seeded varieties including Autumn. There does not appear to be any adverse effects of sowing split seed as a means of reducing seed cost.

Irrigation Management

The response of Autumn and Suzanne coriander to irrigation was studied in 1994. Plots were sown in early May at a seeding rate of 100 plants/m² (approximately 9 kg/ha).

Growing season rainfall during the test was 132 mm. Irrigation treatments of 25, 50, 75, and 100 mm were applied. Irrigation had no effect on seed yield, days to flowering, or seed size.

¹ Calculated as yield x essential oil content

Date of seeding: May 5