Typically in years when soybeans don't get enough rain during their key reproductive time in August, as happened in many locations this year. Seed size is small. That means number of seed per pound are typically higher. That was the case in recent dry seasons.
However, Alan Galbraith, new executive director of the Indiana Crop Improvement Association, says that's not what's happening this year based upon the samples they've processed in their lab so far. Instead, they've found seed size to be normal in most cases, with seed counts per pound lower than in some years when weather really stressed crops late in the season. Not that varieties naturally vary in seeds per pound as a genetic trait as well.
The quality of samples coming in so far appears to be good, Galbraith says. That means that when samples of seed lots submitted to the Indiana crop Improvement Association are tested, they perform surprising well both on the warm and cold germination tests.
Dave Nanda, director of genetics and technology for Seed Consultants, Inc., believes he has a theory which explains why soybean seeds are actually slighter large this year, meaning there are fewer seeds per pound. Knowing how many seeds are present per pound is invaluable in calculating soybean seeding rates today. The emphasis is on hitting a certain population, not on putting on so many pounds per acre.
Nanda contends that because the dry weather and heat set in fairly early in most areas, with the soybean crop planted late, when soybeans were busy making young beans, many pods aborted some of the beans. While Monsanto may talk about five beans per pod and apparently some farmers found some this year, Nanda saw lots of two beans per pod with some threes thrown in in various plots that he looked at this summer."When you only have two seeds per pod, they tend to grow larger because they've got more room and they don't have to share as many nutrients," he says. "The result is larger seed than you would expect from a very dry summer with lots of heat."