Green Leaves Still Sticking on Soybean

Oct 04, 2022

Fall is in the air and harvest is starting up across Iowa. It has been noted soybean are holding onto their leaves. This green bean effect is more often thought of as green stems, however, this year there are more leaves and petioles staying green and attached to the main stem. Take note this occurrence may mean that soybean grain is drier than expected based on plant appearance. This green bean effect can be caused by both biotic (stink bugs, thrips, viruses, etc.) and abiotic (weather, late planting, fungicides, etc.).

Management to avoid green bean syndrome is difficult in-season because of variety of causes. At harvest, the best solution to green bean syndrome is to harvest fields when the soybean seeds are at the proper moisture content. Make sure the sickle bar on the combine is sharp and well-maintained. Slower harvest speeds will be needed to account for more soybean biomass coming through the combine.

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Soybean at harvestable grain moisture with green (and yellow) leaves still attached. (photo credit: Rebecca Vittetoe)

Source : iastate.edu

Video: From Students to Solutions | On The Brink: Season 2, Episode 14

Ask Canada’s most decorated soybean breeder his favourite part of the job and he doesn’t name a single variety. He names the students.

Istvan Rajcan is a professor of soybean breeding and genetics in the Department of Plant Agriculture at the University of Guelph, where he has run the soybean breeding program for 28 and a half years. In that time he has developed 87 soybean cultivars, published 140 refereed papers and trained 51 graduate students. In 2025 he received the Public Sector Impact Award from the National Association for Plant Breeding.

He is also worried. In this episode he says Canada is at a crossroads, pointing to recent government cuts to plant breeding programs and to the facilities that support them. His prescription is structural. "Plant breeding funding formula has to be a long-term one," he says.

The formula he is defending is the public-private matching arrangement his program runs on. Private seed companies fund the work, provincial or federal money matches it, and the combined pool stretches each dollar further than either source could alone. At the National Association for Plant Breeding annual meeting in June, he says American public breeders were often surprised at how well that collaboration works in Canada.

He also describes how the people entering plant breeding have changed. His early graduate students came mostly from farms. More recently they include, in his words, "city kids who just became excited about genetics."

Topics covered:

Why public-private plant breeding funding in Canada needs a long-term

commitment rather than a larger one

How matching private seed company investment with provincial and federal

dollars multiplies research capacity

How the graduate student pipeline into plant breeding has shifted from

farm kids to city kids