By: Wendy McDonald – MPSG Production Agronomist – West
On June 3, 2026 we went to have a look at the three species of lupins that are part of the variety trials seeded at the Parkland Crop Diversification Foundation (PCDF) in Roblin. In the 2026 variety trials there are narrow leaf lupins, sweet white lupins, and yellow lupins.
*Since Australia is the largest producer of lupins in the world, I grabbed this info from a Producing Lupins publication by the Australian Department of Primary Industries and Regional Development. Lupin growth stage photo credit to Deutsche Saatveredelung AG (DSV). The photos are from Roblin.
Lupin seed has two parts: a seed coat and an embryo. You can think of their embryos like an already developed plant consisting of two cotyledons, five or six leaf primordia on a tiny seedling axis and the radicle. Lupin seeds are big and cotyledons account for about 75 per cent of the weight of the seed. The seed coat accounts for almost 25 per cent of the weight.
It’s very interesting how lupins emerge after germination. Lupins germinate epigeally, meaning the cotyledons are pushed up and out of the soil into the air. That takes a lot of energy to do! The point of attachment of the cotyledons to
the seedling axis is susceptible to damage, so soil crusting can cause issues. The loss of a cotyledon will reduce seedling vigour. Cracks in the seed embryo can lead to seedling abnormalities such as a missing taproot or upside down growth.
After germination, the hypocotyl hook straightens and the cotyledons turn green and expand as the shoot grows. The hypocotyl above the soil surface also turns green.
Since the cotyledons and the shoot are above the soil line, lupins can be susceptible to damage from wind blasting, grazing and insect damage.
The first leaf emerges from the cotyledons (the seed coat covered in seed treatment hangs on for a bit). The first true leaf will grow from the centre of the cotyledon and it is actually a leaflet that looks like a little palm tree. (5-10 leaves growing together in a circular fashion)
We did see some lupin plants with bright green cotyledons. Some plants had a touch of brown on the outside edges of their cotyledons, which may have been a little bit of “wind burn”.
Closer scouting found lupin plants with normal stems (no root rot symptoms) but brown tinged cotyledons. Also some plants unexpectedly had all brown cotyledons.
Other plants had brown concentric rings on their cotyledons. Could this be a symptom of Anthracnose? Anthracnose is a disease transmitted by seed with symptoms that can appear at any plant growth stage and can present as dark sunken lesions on the leaves.
Darkening cotyledons and yellowing plant growth were seen in all three species of lupins on June 3 in Roblin. We will continue to monitor, reach out to experts and consider sending plants for testing to investigate further.
Lupin Production Guidelines – Manitoba Pulse & Soybean Growers