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I am a social scientist and I was reading "The political economy of hybrid corn" by Jean-Pierre Berlan and Richard Lewontin.

https://go.gale.com/ps/i.do?id=GALE%7CA4325182&sid=googleScholar&v=2.1&it=r&linkaccess=abs&issn=00270520&p=AONE&sw=w&userGroupName=anon%7E8cf008c1

They claim that the R&D cost for inventing hybrid corn was much higher than the mass selection of corn varieties (Mendelian selection scheme). One reason hybrid corn was adopted was that farmers had to revisit the seed seller every year to maintain their corn yield because the second generation hybrid corn is much less productive, while the selection of a new productive corn variety will make the seed company obsolete once the productive crops are distributed. It was claimed that Henry A. Wallace, the founder of hybrid seed selling company and the son of Secretary of Agriculture Henry C. Wallace, pushed for hybrid corn at the expense of using Mendelian scheme.

I was wondering if there is any academic article or experiment result that compare the productivity hybrid corn versus corns that were developed by "Mendelian selection scheme."

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    – Community Bot
    Commented Aug 29, 2021 at 21:13

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Hybrid corn IS a "Mendelian selection scheme". The issue here is more predictability and uniformity of crop growth and yield.

Normally, plants are genetically varied and having different versions of each gene from mother and father usually increases the fitness of the plant (this is sometimes called "hybrid vigor"). When farmers replant with seeds from only their "best" plants, over the generations the plants become more uniform and predictable in that (good) aspect, but also become more and more inbred (having both copies of a gene be exactly the same instead of slightly different). This inbreeding reduces plant fitness (e.g. yield or disease resistance).

With the discovery of genetics in the early 20th century, farmers realized they could get the benefits of hybrid vigor without the drawback of inbreeding. It's a two step process: separately breed two different varieties of a plant, each highly inbred, then produce seeds in a "seed factory" that have one variety as the "mother" and one variety as the "father". Each inbred parent passes on only the one version it has of each gene, but each (offspring) seed ends up with both different versions of each gene, one from each parent.

The resulting hybrid seeds called "F1" are both genetically uniform AND show "hybrid vigor" because each has two different versions of every gene. They just don't breed true, as the different versions of each gene get mixed up again ("reassorted") in further generations.

However, as long as the two original inbred parent varieties are propagated (remember, they remain genetically identical as they are inbred), the F1 hybrid offspring seeds can be recreated whenever desired. This naturally leads to a larger organization (like a company) maintaining the two parent varieties and continually producing reproducibly uniform F1 hybrid seeds for farmers to actually use.

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    $\begingroup$ Thanks for the detailed explanation. My understanding of Lewontin's article was that non-hybrid seeds that were properly developed would have been better than hybrid corn. Does that sound outrageous? Thanks $\endgroup$
    – hbkn
    Commented Aug 31, 2021 at 3:45
  • $\begingroup$ It seems quite unlikely. After all, nothing is stopping farmers from using non-hybrid seeds; if they didn't see an advantage to buying the hybrids, they wouldn't do so. The complexity comes in when you deal with multiple features of the plant. For example, maybe a given "heirloom" (inbred) variety has a special taste that nobody has been able to incorporate into a hybrid, so a farmer is willing to accept a lower yield or less hardy plant because they can get a significantly higher price for the product at market. In home tomato growing both hybrids and heirlooms seem to hold their own. $\endgroup$
    – Armand
    Commented Aug 31, 2021 at 6:23
  • $\begingroup$ >"Hybrid corn IS a 'Mendelian selection scheme'." You've missed the point: that true-breeding (and predictable and uniform) vigor might also have been possible to select for, but seed companies didn't bother trying, since it would have let farmers replant seed—unlike the hybrid-corn business model of making farmers buy new seed each year. (Tl;dr if hybrid vigor is because of heterozygote advantage at various loci, you couldn't select for true-breeding vigor. If it's because of dominant good genes in each parental strain covering up recessive bad genes in the other strain, you could.) $\endgroup$
    – David Bahry
    Commented May 4, 2022 at 4:31
  • $\begingroup$ @DavidBahry We've learned a lot in the past 15 or so years of the genome era. One of those lessons is that in real life different alleles of a gene are not all good or all bad; in fact, many genes have multiple functions as part of the same gene! This has supported the assertion that hybrid vigor is due in large part to heterozygote advantage rather than just increasing the proportion of loci with "dominant good genes". In this case, it seems the business model is indeed supported by the science. $\endgroup$
    – Armand
    Commented May 4, 2022 at 5:55

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