understanding corn genetics

[Deleted]

One thing I'm still unsure about is heat units versus daylength in tropical corn. If tropical corn "X" begins reproduction when days are 13.25 hours, let's say, then would it be better to plant it later so that it won't develop "stretchy" growth during the long days and lodge, seeing as how it will flower at that particular daylength regardless of its size? It wouldn't do anything worthwile to start "X" indoors a few weeks earlier and transplant, would it, since heat units wouldn't really matter?

And you're right, oxbow. I just don't want to select so heavily that the plants become somewhat inbred and lose their vigor.

[blueadzuki]

This upcoming year I am planning to plant out a corn mix that contains all or nearly all (I try and aviod totally using up any seed I plant, so there is always a little backup) of waht I ahve left of the Andean corn I picked up in NYC in 2009-2010. That stuff basically did nothing the last time I grew it, since once the whether turned hot, it basically went into stasis until autum. So it is my plant to start it really, really early to give it the maxiumum time in the cool (I'm sort of banking on the predictions stated on this forum that the next two years here in NA will be similar to the previos one (for me); a long cool to cold spring followed by a short hot summer and an early autum cool. It probalby won't be enough to get actual ear growth from any of it, but I may be able to get enough pollen (and if necessary, hold enough pollen in my freezer) to be able to cross it to the "normal" (read "local") corn selections I am planting; hopefully I'll get something out of the cross that has local season requirements with a bit of the Andean size and color patterns. If I can get my hands on enough medium pots, maybe I'll even start them inside so that I can plant ready made hills. which would also help with the problem of getting the beans round them (more often than not the beans climb away from the stalks and crawl on the ground until they die from lack of support (or being stepped on becuse they have covered every way through the corn) and tieing them to the corn often girds the stalks)

[Joseph Lofthouse]

Even if corn falls over during the growing season, it will often continue growing and produce pollen and/or seed. There are other anti-lodging strategies in addition to brace roots, for example large tap-roots, and/or tillers, and/or stiff stalks, and/or planting in hills, and/or soil modifications.

With the tropical highlands corn I am growing, it ends up about the same size/condition whether I plant it in March or in July. Either way it doesn't mature seeds for me. Either way it grows prostrate. However, the southern corn produces pollen, and if I could time a planting of northern corn properly a cross with a northern mother would likely mature before frost. Someone recommended planting the Mexican highlands corn on the East side of a building to mess with it's sense of day-length. I haven't tried that yet. The inventor in me wants a curtain under the eves of the house that auto-closes after a certain amount of day-length.

I'm pretty cavalier about discarding phenotypes that don't work for me... I'll make the cross with foreign stock, and then take from the F2 or F3 whatever works for me.

I have not observed hybrid vigor in my corn breeding projects. The phenotype of the children tends to be mid-way between the phenotypes of the parents.

I suspect that hybrid vigor may be another plant breeding myth propagated by The Corporation in order to bedazzle people into buying new hybrid seeds every year. I know intellectually that after 6 generations of inbreeding that a corn cultivar can get sickly and that crossing it with another highly inbred sickly variety may result in better growth than the sickly parents... But I don't know any maintainer of an open pollinated corn line that is creating such unnatural sickly inbreeds.

I am not creating extremely inbred lines, so there is no reason for me to expect hybrid vigor in my corn. If there is any hybrid vigor effect in my garden, it is very subtle, something that could only be measured by meticulous statistical analysis, not something that I'd be able to see just by looking at the offspring.

[Deleted]

So in other words, Joseph, it would be better for me to plant my Jala corn (finally got some ) later in the season so that it won't grow to the grossly oversized height some people want before finally tasseling? And, blueadzuki, what type of Andean corn was it? I saw a picture of someone in Arizona growing Cuzco Gigante, and it seemed to grow fine from its May (or thereabout) emergence to silking in early August. Perhaps it's only the strains from WAAAAAYYYYYY up the mountains that freeze growth? Here are the pictures:

www.delange.org/Cuzco_Maize_Giant_White_Corn/Cuzco_Maize_Giant_White_Corn.htm

[Joseph Lofthouse]

I am only growing one corn from the Tropical Highlands race. It is endemic to Oaxaca... So I am not the one to be asking about how to grow southern corns... But not knowing what I'm talking about has never shut me up before....

My variety grows to approximately the same size whether I plant it in March or July. Tasseling is slightly earlier if planted in March, but two weeks difference at the end of October when daytime temperatures are in the 60s is hardly noticeable.

[blueadzuki]

Nov 25, 2011 19:09:33 GMT -5 @bjargakarlinn said:

And, blueadzuki, what type of Andean corn was it?

What I have is some multicolored corn of the type that IS from really high up the Andes (apart from the fact that it is colored, it somewaht resembles the stuff sold in some Latin American supermarketsv as "Cancha de Montanas" (with a tilde over the n)
the cobs have the typical high andean shape (much shorter and wider than most North american corns, with very big (though not as big as Cuzco) kernels somtimes pointed, so that the whole cob often resembles a pine cone) most of them (well most of what I saved) have blue or purple spots, many are red or tan, and some have a pattern that I describe as "turkey feather" (numerous overlapping dark edged scales (though I'n not sure if this is a legitiamate pattern or some sort of damage or indeed if it is in the pericarp or aleurone. There is also one cob with the Morado colr (dark dark purple) and 12 or so chinmarked that have sweet corn genes I suspect the stuff was pretty old when I got it; the cobs had numerous dabs of superglue on them to stick them back in place (they were being sold as Indian corn for doors) and germination is only about 35-50% unsually (and the seed is now 2 years older than it was then, so it may be even lower now.)Part of why I'm planning to plant it this upcoming year is that I have a feeling that, if I wait another year, viability will drop to functionally 0.

[Deleted]

Joseph, if the Oaxacan strain doesn't work out for you, we'll be growing an Andean composite from the USDA next year. It's 96% Andean with 4% Northern cornbelt parentage for early maturity. I'd be happy to send you some seeds from the earliest lines if it does well for us. We also have a Guatemalan-Cuban-Colombian USDA composite with photoperiod neutrality. I'd be happy to send you seed from its earliest lines too, if you'd like. (It's tropical lowland mostly, but exotic genes all the same.) Blueadzuki, the same offer goes out to you, if you'd like.

[Joseph Lofthouse]

Thanks for sharing. My seed is also readily available... I feed lots of nice breeding stock to the chickens so don't be shy about asking for seed. There is plenty to go around.

[Deleted]

You're welcome. I mentioned the earliest lines because of the "~100 frost free days" in your profile footer, but if you have a greenhouse or some other means of growing later strains, then I'd be happy to send you some of those too. I have 20 corn varities planned for growout next year, so if a trait exists, then I'll probably have it!

[Joseph Lofthouse]

My eyes glaze over and my brain goes numb when I think about trying to grow a 150 day corn.

I really appreciate short season crops. It helps if they come to me already somewhat adapted. I tried growing Seminole squash which was endemic to Florida. Oh my gosh! The growing season that year was 88 days. I didn't even get blossoms.

The ~100 frost free days applies to very tender crops like cantaloupe and cucumbers. I have a bit longer growing season for somewhat cold tolerant crops like corn. My corn generally survives late spring frosts, and early fall frosts, so I might could stretch that to ~150 days that corn would stay alive in my garden, but the extra 50 days is during cold weather when corn doesn't grow very well anyway. I could attempt a 110 day popcorn, but a 120 day corn would too long.

One of my brothers has a greenhouse that we use for growing tomato and pepper starts. We've never used it for fall season extension, but it would be great to finish maturing a short season corn that had been pollinated with a late tasseling southern variety.

[Deleted]

"My corn generally survives late spring frosts, and early fall frosts, so I might could stretch that to ~150 days that corn would stay alive in my garden."
I've often wondered about corn's resistance to very light frosts. Typically the weather warms back up for another solid 2 weeks or so after the first fall frost here, which is about how long some of my tropicals would need to finish ripening. How much damage do your corns take after a light frost? Do you think kernels about 1-2 weeks away from the black layer stage would be hurt by a light frost? The way things are looking, my Cuzco Gigante should silk here around August 14, and our first 32 degree dip comes around October 7th, just a week before the dry corn is ready to harvest. What has been your experience?

[blueadzuki]

Nov 25, 2011 23:15:13 GMT -5 @bjargakarlinn said:

Joseph, if the Oaxacan strain doesn't work out for you, we'll be growing an Andean composite from the USDA next year. It's 96% Andean with 4% Northern cornbelt parentage for early maturity. I'd be happy to send you some seeds from the earliest lines if it does well for us. We also have a Guatemalan-Cuban-Colombian USDA composite with photoperiod neutrality. I'd be happy to send you seed from its earliest lines too, if you'd like. (It's tropical lowland mostly, but exotic genes all the same.) Blueadzuki, the same offer goes out to you, if you'd like.

Thanks, but I selected the Andean kernels that are being planted specifically because of thier patterns that I want to mix with my stippled; a random sample from somewhere else would likey adulterate the patterns I am after right out of existance.

[cortona]

bjargakarlinn if you next year can consider me for an excange or trade with some of your corn line i'm very interessed, looking for flour or flint corn to create a drought resistent landrace for my climate(i think i can /must split the progect in two: one realy hearly maturing and cold resistent that i can plant as weater permit and one that are more drought resistence but longer season) i can andle in good year a 150 d t m corn but probably not flour corn that mold easily because in normal year october/november is a realy rainy period(wel: "the rainy period" usualy)

[Deleted]

Cortona,
Drought tolerance isn't something that I can test for on a consistent basis, being in one of the wettest parts of my state (we only have dry summers sporadically through the years). However, I am planning a cross between Virginia Gourdseed and a Southwestern dent next spring, so I could send you some crossed seed in the fall, and you could select for drought tolerance the following years. As for a cold resistant and early variety, I'll also be doing a cross between Rhode Island White Cap and Roy's Calais, so I could send you some seed from it. Cross the mix with Painted Mountain the following year, and you'd have a very early and cold-hardy corn. I'm planning on doing that very thing myself in the next couple of years.

[DarJones]

Drought tolerance is an interesting trait. Sandhill carries a variety named Drought Tolerant White that I am interested in but mostly because I would like to compare it to a drought tolerant variety that I have grown and saved seed from for several years. Most drought tolerance in corn of U.S. origin is just because of a larger than normal root system. CIMMYT has several lines selected specifically for drought tolerance that appears to be based on metabolic traits which is an entirely different concept from the tolerance that I am familiar with.

DarJones