Serendipity at Maize Genetics

While at the 2011 Maize Genetics Conference, the Biofortified Executive Editorial Team (Hey that spells BEET), aka Anastasia and I, talked about many of the awesome things that have made it onto the blog, and things that have not yet done so. One of the craziest things that I learned from a fellow graduate student while harvesting ears of corn in the field last fall were the Oat-Maize Addition Lines. People often frame their opinion of genetic engineering based upon the likelihood that some genetic phenomenon could happen on its own, by chance. So breeding within a species – that’s ok because that happens already. Moving octopus genes into primroses – maybe not so likely. Essentially, if it can happen through pollen then almost whatever genetic change you can think of in plants to some is all good. Actually “Organic” Breeding is based on that principle. So moving genes from corn plant to corn plant raises few people’s eyebrows. If you were to suggest moving a gene from a maize plant to an oat plant – then you might as well be breaking a fundamental law of nature.

What if you found out that maize can cross with oats? Ron Phillips, Regents Professor Emeritus at the University of Minnesota, gave a talk on parts of his career as a plant breeder, and he focused on the role of serendipity – of fortuitous chance events, in the life of a scientist. And one of his serendipitous discoveries was that you could, against all boundaries we humans apply to nature (in our minds), indeed cross maize with oats. So we grabbed him for an interview to talk about the amazing Oat-Maize Addition lines and more. The right person to explain these plants to everyone on video – right there for us to interview, how’s that for Serendipity?

So what do you think, is an Oat plant with one Maize chromosome a “GMO” or something else?

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Karl is a Ph.D. Candidate in Plant Breeding and Plant Genetics at UW-Madison. In addition to his research on the genetics of sweet corn, he is also completing a minor in science communication and is working on several media projects about plant breeding. His favorite produce might just be squash.


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26 comments to Serendipity at Maize Genetics

  • So, now I’m waiting for the blog post on this (as I am averse to watching videos).

    Still waiting.

    *stares*

  • OrchidGrowinMan

    Very cool: as PZ and others have pointed-out, we as a society need to make it possible for SCIENTISTS to be seen as role-models, heroes, ‘rock stars’. (Maybe we should introduce trading-cards?) I wish this video had better production-value (no offense).

    Anyway, aside from the coolth of Avena’s receptiveness to xenochromosomes, which may be unique, Embryo Rescue is a very cool and useful technique, along with germ cell culture and others. I wonder how many OTHER accidental unexpected wide crosses are possible if that kind of assistance is made available? Triticale!

    I love ploidy-bending. Does than make me a perv?

  • Eric Baumholder

    I went looking for pictures of the Oat-Maize crosses, and found none. Any chance this would be a valuable cultivar? Oats yields well in poor soil conditions, and it’s high in mineral content. Oh, and OT: did you folks have a denial-of-service web attack yesterday? all I could get was ‘Network Error’.

  • OrchidGrowinMan

    Eric,

    The link in the post has lots of pics. All of the progeny are apparently just somewhat impaire oats; I think some further breeding would be needed to see if they are actually valuable as crops.

    That said, I wish we had a transcript for poor Ewan, and for me. Better yet, a technical paper. There’s a list of references at the site (site cites); which is best for limited-time readers?

    Oh, and I’ll second the Q re yesterday: I though I’d finally been banned when I kept getting the “refused” error….

  • 2001 Plant Phys paper with pics of the poor unfortunates

    seems that you don’t particularly get anything commercially viable – there does however seem to be the potential, through irraiation, to induce crossovers between maize chromosomes and oat chromosomes – one wonders how GMO this would be seen (as presumably in a large enough population this would occur naturally) and whether it could be used to improve oats (assuming any single corn gene would be beneficial to oats)

    • Maybe one could identify useful maize genes in oats through transgenesis, and then screen and irratiate addition lines that have the gene of interest.

    • Eric Baumholder

      Finally got to the pix. It’s amazing that the cross of two quite completely domesticated plants results most often is what most people would consider a weedy grass. However, Sun II x B73 looks promising.

      I’ve often thought we could get more bushels/acre if more of the corn plant went into production of ears, and less to the production of stalks. Back in the day, tall stalks were considered important to weed control — the tallest cultivars earliest in the season were prized.

      With HT technology, tall stalks are no longer that important (unless you’re selling biomass on the side). So one might have corn with, say, reliably three ears, with stalks perhaps three feet tall. Getting there with conventional breeding or embryo rescue would be difficult, but with gene sequencing and finding the genes of interest, a transgenic approach would seem to be the fast track.

      As an aside, I wonder if anyone’s done work with maize x sorghum. Sorghum is considered very drought-hardy and amenable to cultivation in marginal soils. Could work better than maize x oat.

      • The problem with more ears, rather than say bigger ears (which pose their own problems in terms of lodging) is that you invest all that carbon in the stupid junk that carries the kernels – multiple ears on a plant generally suggests (to my untrained eye at least!) that you ain’t planting densely enough – at least for field corn – perhaps sweet operates by different rules – as such I dunno to what extent shorter corn would benefit – the plant really does a pretty fantastic job of remobilizing accumulated resources into the ear as is, so perhaps height is a good thing (you can think of lower leaves less as photosynthetic factories and more as photosynthate warehouses (which makes sense if you’ve ever seen how dark it is a few leaves down in the canopy)

  • OrchidGrowinMan

    Ewan,

    “perhaps sweet operates by different rules”:
    I discovered something as a child, and so did at least one of my Chinese acquaintances: (sweet) corn stalks are just like sugar-cane! So there is some apparently wasteful allocation of carbohydrate. I don’t know about field corn though.

    Karl,
    Ewan,

    “identify useful maize genes”
    “any single corn gene would be beneficial to oats”
    One word: carotenoids.

    • Hmmm, Orange Oatmeal? That’s not a bad idea. For one thing, the Maize Phytoene synthase gene works well in rice, better than the original daffodil gene used in golden rice. And given the close relationship of these two grasses, maybe it will be expressed in the right tissues. I wonder how many genes for this pathway are expressed in oat endosperm already? It might be just one or a few genes to add to get the desired effect.
      I wonder if our new oat breeder at UW Madison, who developed orange maize, would be interested in trying to make orange oats?

    • Eric Baumholder

      OrchidGrowinMan,

      I can vouch for the fact that corn stalks (yellow dent) are as sweet as stalks of sugar cane. That element is likely what justifies chopping immature corn for silage. So there might be a trade-off between cultivars maximized for silage, and those maximized for grain.

    • Ewan R

      When during the season are we discussing when talking about sweet stalks? (I’m guessing from Erics comments that this is immature corn, or early reproductive) – you can make a relatively convincing sugar cane surrogate out of corn by simply removing all the ears – with nowhere for the sugars to go they end up congregating in the stalk (or so I’ve heard) – you’d hope that by R6 you’d have a non sweet stalk – I’m guessing sweet corn is picked before you reach dry down (not much of a market for sweet corn with 15% moisture…) so perhaps the stalks still retain some sugar.

      • I helped out a postdoc in my lab two summers ago, and we prevented the ears from being pollinated so there was no ‘sink’ for the carbohydrates to go to. The result was stalks that are really sweet with sugar, kind of like sugar cane.

        With regard to Eric’s suggestion that you just breed short plants with tons of ears, you may run against the biology of the plant if you do that. Carbohydrates are stored in the leaves as starch for when the sun is not out, and transported through the plant as sucrose. (And apparently stacks up in the stalk. Before pollination, the plant is storing up a lot of this carbohydrate in the very green tissues that Eric is suggesting that you reduce. When pollination occurs, the carbohydrates are mobilized to travel to the new sink – the developing ear(s), where it will then get converted to starch. So if you reduced the green plant material, you may reduce the source of the carbohydrates and the total capacity of the plant to mobilize sugars to the ear. There is still probably some room for modifying the plant, such as breeding for impaired mobilization (for biomass) or improved carbohydrate allocation in the ears.
        You could think about it another way – regular apple trees vs apple trees on dwarfing rootstocks. Are the apples any more numerous or sugary on the dwarfing rootstocks? It doesn’t sound like it, although it means you do don’t have to reach so high to pick them.
        I don’t think sweet corn would give you much of a biofuel benefit for several reasons. First, the overall carbohydrate content of the kernels is lower even though sugars are higher. Second, after harvest, the sugars are slowly converted into starch during storage. Some genotypes do this slower than others, such as those with the shrunken2 allele (sh2), but it means that if you were going to try to capture the highest sugar content you would have to grab them within a narrow number of days and process it immediately. Finally, the total carbs per acre will probably be lower than for field corn.

      • OrchidGrowinMan

        Ewan,

        After harvesting the sweet corn, the stalks are still sweet, and maybe become more so if left standing.

  • OrchidGrowinMan

    Eric,

    We’re already using triploid and short-day corn for silage and ethanol (presumably(?) from the stalk sugar): the idea is to AVOID grain production. In fact, wouldn’t sweet corn grain be better for ethanol, avoiding amylase or HCl expense?

    And yes, I would vote for orange oatmeal. Purple too, if that’s feasible! I’ve never understood why people would prefer white food: white peaches, white-fleshed apples, white beets and white corn are popular, and I can think of no justification (well, a few, especially sugar beets).

  • Hi folks. Your topics and posts are very interesting. First, I just want to say that I work with a farmer who grows a variety of popcorn that grows approximately 3 ft tall with 2-5 stalks (bushlike) and can produce up to 36 ears per plant. Normally 8-12, but the farmer and his predecessor found the record 36 ear plant about 15 years ago. When Gene started helping Richard in the late 80s, the plant yield was about 600 lbs per acre with kernel size approximately 11,250 kernels per pound (seriously). Gene’s efforts to use seeds from the strongest plants and his work with micronutrients brought yields up – today our average is over 1,500 lbs per acre and we are relaunching his line of popcorn (Tiny But Mighty) in the Midwest after the 2 years of floods almost ruined his family business.
    I ran into your posts after meeting Anastasia on Twitter. Something I mentioned on Twitter or the website was not highly accurate and I’m hoping to learn more about the science behind what I’m selling. My background is a huge science and ecology fan since I was young. Studied rainforest ecology and coral reef ecology while in high school with great field trips to Belize and Costa Rica. At Boston College I felt that the science route was preferred, but my talents would be best used in business so that I could hopefully bring those skills back to the science world. Although I was able to study reefs and marine science briefly while in Australia, my time in college was split between management and comparative theology.
    Now while almost complete with an MBA from University of Chicago – serendipity (or familyfarmed.org) :) put me in contact with Gene and his family. Over the past 15 month I’ve learned so much about his unique corn and am fighting to properly finance his comeback! Progress is good, but still a ways to go. This year ill be growing 100 plants in my parents’ yard in suburban Chicago. Gene gave me the recessive red kernels that come off our ears to plant and see what happens.
    I have no problem with the science of agriculture. My worry is that this is heavily driven by our commercial needs as a global civilization. I just hope that as we evolve as a culture in the 21st century, we don’t get too confident in our scientific abilities that we allow unique varieties of plants to become extinct and forgotten. Farmers (as a general group) follow science and business – if driven entirely by experimentation and commercial supply/demand there may be a time that we look back and say: “I wish a few more people had focused on those interesting, but less profitable plants” – I am not an expert, but I don’t want us to always be rushing evolution.
    Let me know what you think about our corn! So far the experts have not been able to give much insight other than it seems to be a relative of flint corn, but there is no genotype on record to match. I just find it amazing and awe-inspiring that we can still find hidden gems like this in a world that seems highly ‘discovered’.

    • Hello Kevin! Thanks for stopping by, I hope you come back and join us for other conversations. The more voices and more opinions the better!

      For anyone that hasn’t heard of it, I think TBM is a really interesting popcorn for a lot of reasons. On the entirely practical side, it’s nice that the husk doesn’t stick in my teeth. I’m not sure if it actually tastes different, I’d have to do a blind taste-test. On the science side, it’s nice that a single variety is being cultivated and sold for a change, instead of commodity grain where all the varieties are relatively similar and just bulked together.

      TBM is a unique opportunity to tell a story about a variety and let people know why in-species diversity is important. While the claim that it’s been “unchanged for thousands of years” is exaggerated, it is fairly unchanged from older cultivars. It’s certainly more like older varieties than modern hybrids, yet it is still useful in its own way. I’d love to see more detail shared about the variety. Instead of the simple “unchanged” line, how about a more nuanced story about how the traits that make the corn special have been painstakingly maintained over the years despite genetic drift and despite influx of pollen from other varieties? How about a story of how the variety has been changed little by little to make a better corn that includes many traits from a more ancient variety?

      I am concerned about some of the statements on the website. The way things are stated now, it seems that TBM is implying that modern varieties and genetic engineering are wrong. On the “Our Popcorn” page, it says that TBM is wholesome and natural, implying that everything else is unwholesome and unnatural. How would you feel if other farmers started putting your product down? Instead of putting other products down, how about emphasizing what is good about TBM? The claim about near-extinction of other varieties is exaggerated too, there are a lot of programs that actively work to maintain maize biodiversity in private and public sectors. I don’t know what you mean by getting “too confident in our scientific abilities” (the alternative is confidence in…?) but I disagree that using science to better crops equals forgetting about germplasm. I do agree that it is awe inspiring that we can find hidden gems in the form of entire lines as well as in the form of individual traits.

      To get back to your comment, Kevin, first of all, congrats on your progress on your MBA! I hope you are able to do all that you want to do with that great education. As for the specific details on the TBM variety, do you know if Gene has talked with the people at the GEM (Germplasm Enhancement of Maize) project? They have a lot of material, surely some are fairly similar to the TBM variety. If you are interested, I can get you in touch with them. I wish you good luck with growing your 100 plants this season!

    • “I wish a few more people had focused on those interesting, but less profitable plants” – I am not an expert, but I don’t want us to always be rushing evolution.

      Hence the need to properly fund ag research – corporations simply ain’t going to focus on crops or varieties that don’t pay off – universities can (although I suspect with the amount universities have to rely on money from business this is somewhat stymied) and should and seed banks etc – what we need to avoid doing, rather than being too confident in science, is being too confident that “the market” is going to preserve what is best – nobody would say, from a scientific standpoint, that getting rid of varietes utterly is a good idea (scientists understand that variation is a good thing ™ – indeed the strength even of a commercial breeding program lies not in the performance of the best inbred line, but in the breadth of variation from which the breeders can select) – if we rest on our laurels and note that as agribusiness spends billions on Ag R&D we can therefore cut funding then we’ll be in a far crappier place in coming decades.

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