Ethiopian Coriander Flowers Gave Their Best Nectar in the Afternoon

The full story

What Happened? [1]

Researchers at Adami Tulu Agricultural Research Center in Ethiopia compared two improved coriander varieties, Batu and Tulu, as possible forage plants for honeybees. They tracked flowering, bee visits, pollen, nectar volume, and nectar sugar concentration under rainfed field conditions. [1]

Both varieties produced more nectar later in the day than early in the morning. The study presents coriander as a possible component of bee-forage planting in this particular semi-arid setting—not as a guarantee of a particular honey harvest. [1]

Why Should We Care? [1]

For bees, a landscape is also a meal schedule. Knowing when flowers offer nectar can help researchers and beekeepers think about how crops might complement other blooming plants. [1]

This study suggests that coriander deserves further consideration as one locally tested forage option in Ethiopia's Central Rift Valley. But its estimates describe the nectar resources calculated from flowers in experimental plots; they do not show how much saleable honey a beekeeper will actually collect. [1]

What Did the Researchers Find?

The researchers compared Batu and Tulu coriander in a randomized complete-block field design with four replicated plots for each variety. [1]
Nectar volume and sugar concentration varied significantly by time of day; both varieties generally showed their highest nectar volumes in the afternoon, especially from 15:00 to 18:00. [1]
At 15:00, mean nectar volume was 1.92 microliters per flower for Batu and 1.50 microliters for Tulu; the table reported lower values at 06:00 for both varieties. [1]
The two varieties did not differ significantly in reported pollen yield, flowers per plant, or observed bee visits per square meter. [1]
The paper calculated honey-production potential from floral density, nectar sugar per flower, nectar-secretion duration, and an assumed honey sugar content; it did not report harvested honey from colonies. [1]

How Do We Know? [1]

The team grew the two varieties in 3-by-3-meter rainfed plots at Adami Tulu Agricultural Research Center. To measure nectar, they covered flower heads with mesh to prevent insect visits, sampled flowers over three consecutive days, and measured nectar volume and sugar concentration at three-hour intervals from 06:00 to 18:00. [1]

They analyzed nectar traits by variety and time of day using analysis of variance. The paper also describes observations across the 2021–2023 production seasons. These procedures support a careful comparison at this site, while leaving important questions about other places, years, and farming conditions open. [1]

What Doesn’t This Study Prove?

Potential honey is not harvested honey. The reported honey figures were calculated from floral and nectar measurements using assumptions about sugar content. The study did not place colonies, measure colony condition, or report an actual honey harvest, so it cannot predict a beekeeper's realized yield. [1]

Weather associations are not proof of cause. Temperature and humidity changed naturally in the field rather than being experimentally controlled. The authors state that controlled studies would be needed to establish causal effects or identify exact temperature thresholds for nectar production. [1]

This was a local comparison of two varieties. The evidence concerns Batu and Tulu grown at one Ethiopian research center under the reported field conditions. It does not establish that all coriander varieties, farms, climates, or bee colonies will behave the same way. [1]

The paper reports conflicting honey-potential figures. Its abstract describes estimates of 35–39 kilograms per hectare, while the results section also reports a 58.2–130.2 kilograms-per-hectare range and an approximately 100.5-kilograms-per-hectare mean before restating the lower range as a conservative interpretation. Visitors should not treat any single figure as a settled yield estimate without author or publisher clarification. [1]

Where Did This Research Come From?

Research Record

Original Study: Honey production potential and nectar secretion dynamics of improved coriander varieties for bee forage development at Adami Tulu agricultural research center, Ethiopia
Authors: Mekonnen Wolditsadik Beyi, Gemeda Terfassa Fida, Taye Beyene Lema
Journal: Scientific African
Publisher: Elsevier BV
Publication: 2026-09
Honey Chronicles Timeline Date: Forthcoming — timeline placement pending
Journal Issue Date: 2026-09
Volume: 33
Pages / Article: e03470
Species Studied: Coriandrum sativum L.
Research Location / Affiliations: Adami Tulu Agricultural Research Center, Central Rift Valley, Ethiopia; Oromia Agricultural Research Institute (IQQO), Adami Tulu Agricultural Research Center, Ziway, Ethiopia
DOI: 10.1016/j.sciaf.2026.e03470