SM1791's picture
Isn't it better for farmers to harvest and reuse their own seeds?

A:Expert Answer

Most farmers do not choose to save seed because they can be assured that newly purchased seed is free of disease and pathogens, and in the case of hybrids, demonstrates hybrid vigor, with consistent, uniform characteristics. 


“Seed saving” is not really an option with hybrid corn if a farmer wants consistency in his or her crops because saved the seed from hybrid crops (the offspring) does not “breed true” in successive generations, i.e., it does not deliver the quality and uniformity that farmers need.   In soybeans, studies have shown that farmers get better yields when they buy new, “certified” seed rather than saved or “bin-run” seed.  As Successful Farming magazine pointed out:


“Shawn Conley, a University of Wisconsin Extension agronomist, analyzed data that North Carolina State University researchers published in 1991 comparing bin-run to professionally grown seed. The researchers analyzed 204 comparisons across 6 years in 16 locations with 35 varieties. They found a 1.9 bushel per acre advantage to certified seed over bin-run seed. In some cases, they were higher. Conley notes Wisconsin data showed a 2.2 bushel per acre advantage for certified over bin-run seed.  Today, this difference would likely be magnified due to improvements in seed technology, he adds.”


("Why it doesn't pay to plant bin-run soybean seed," Successful Farming, February 12, 2013)


Hybrids can be explained easily by revisiting high school Mendelian genetics 101:


When you cross two "true-breeding" parental varieties you create a hybrid.  To be "true breeding,” the plants’ genes would have to be homozygous for whatever traits are desired.  That means both alleles of a given gene would be either dominant (AA for example) or recessive (aa for example).  For example, in looking at three genes, A, B and C, the genes in true breeding parent 1 could be AAbbCC and parent 2 could be aaBBcc.  Each parent would be genetically different.  


The hybrid offspring of these parents (crossing AAbbCC x aaBBcc) would be AaBbCc:  one allele from each gene comes from parent 1 and the other allele from each gene comes from parent 2.  The ears of corn (the offspring), which are genetically different from their parents, are harvested.


If you purchase new hybrid seed the next year that was produced again from the true breeding parents above, you will continue to produce corn plants that are genetically the same as the previous year’s crop (AbBbCc). 


If on the other hand, you save the kernels from this offspring corn (AaBbCc) and plant them next year, the growing corn plants will fertilize themselves and each other. (Corn is wind-pollinated.) 


The offspring of this cross  (AaBbCc x AaBbCc) can produce a variety of 16 possible genetic combinations: AABBCC, AABBCc, AABbCC, AABbCc, AaBBCC, AaBBCc, AaBbCC, AaBbCc, AABBcc, AAbbCC, AAbbcc, aaBBCC, aabbCC, or aabbcc, half of which would not look like the parents.


Rickinreallife's picture

It is an intuitive and rational perception that if you could save a portion of your crop to use as seed for the following season, and indeed if this was a common practice in the past, it doesn't seem to make sense that a producer would voluntarily choose to purchase seed each year. Thus, seed companies must be in some manner conning or coercing producers to engage in what appears to be economically irrational behavior, right?

An alternative explanation is that it doesn't make sense for a producer to do so unless there is some value in doing so. Actually, planting saved seed is not cost or risk free. You lose the ability to earn income from a portion of the crop saved. In a low yield year, you still have to save the same amount of seed to have enough to plant, so the % of crop available to market or use would be reduced. If a growing season had numerous stresses, like drought, the germination and performance qualities of the saved seed could be disappointing and reduce yield potential the next year. Also,you take the chance that the seed will be damaged or destroyed in storage between growing seasons and you'll have the expense of purchasing seed anyway. There is often expense of cleaning and conditioning of saved seed, and this is particularly important to avoid saving weed seed along with the saved seed so you are not just planting weeds as well. Purchased seed can usually be relied on not to contain weeds. I worked for a wheat producer growing up who planted saved seed but still purchased new certified seed every 3-4 years in part due to genetic drift and the yield stagnation you talk about, and to acquire new wheat varieties that might come along that might have desirable qualities that his current seed didn't, say a new variety that was resistant to wheat rust.

When hybrids first came out, many farmers probably didn't abandon seed saving altogether. Instead, they might have tried some of the new hybrids on a portion of their land, and were sold on purchasing hybrid seed each year only if the yield and income and perhaps other values of the hybrid variety outweighed the cost. Likewise, crops with biotech traits (which aren't a wholly seperate category of plant that replace hybrids, they are the same hybrids that have merely additional genetic information that endows the hybrid with some desireable quality like herbicide tolerance) were not necessarily automatically purchased by producers. They likely experimented with biotech varieties on small portions, or observed their neighbors experience, before they would have been convinced that the additional cost was worthwhile. It is understandable that biotech traits were rapidly adopted by farmers because they delivered tremendous value, both in helping to manage growing season stresses that tend to not allow the crop to reach its yield potential, but also in a sharp reduction in input costs, the combination of which more than offset the higher expense. Herbicide tolerance enabled the producer to control weeds effectively, sometimes with a single application to a growing crop, of a product like glysophate that controls a broad variety of weeds, replacing having to apply a variety of products in multiple applications because they only targeted a limited range of weeds. Roundup ready technology became available about a decade after conservation compliance became a requirement for participation in federal farm programs. Herbicide tolerance made conservation and no-till which are great for reducing erosion and building soil quality in their own right, but helped producers meet the conservation requirements of the farm bill. Glysophate has a lower residual presence, and thus allows more flexible crop rotation choices. Herbicide tolerance also allowed producers to avoid several tillage trips, reducing fuel costs and machinery investment and depreciation. In the mid 90's, it was estimated that one tractor was needed for every 350 acres. Today, because of no-till, one tractor might be suffient for 900-1000 acres.

There has been a lot of environmental and agronomic value brought about by biotech enhancement of crops thus far, and some of the qualities in the pipeline, e.g. as nitrogen use efficiency genetics, will likely help further reduce production inputs and costs while maintaining yields, and I believe stimulate the ability for conventional farms to replace at least a portion of purchased nitrogen fertilizers.

Jenna E Gallegos's picture

Here is a short video by scientists at UC Davis explaining the genetics behind hybrid vigor: