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Post by DarJones on Dec 17, 2012 15:07:58 GMT -5
I am setting up a project to evaluate cold tolerance in some wild tomato species and in some domestic tomato lines from various sources. Here are some of the notes made to date for the evaluation. Most cultivated tomatoes are distinctly unhappy at temps below 60 degrees. Virtually all of them stop growing below 45 degrees. Leaves freeze at about 28 degrees for most of them and any amount of frost on the leaves usually kills them. Frost can form under some conditions at 35°F which means that tomato plants have to be protected in humid climates at or below this temp. Some plants are capable of surviving temps below freezing. In particular, some Russian work identified rare individual plants that survived temps down to 8°F. I have seed of a few of these cold tolerant tomatoes being mailed from Andrey. sadoved.com/3798-saraevskie-tomaty-zamechatelnoe-nasledie.htmltranslate.google.com/translate?sl=auto&tl=en&js=n&prev=_t&hl=en&ie=UTF-8&eotf=1&u=http%3A%2F%2Fsadoved.com%2F3798-saraevskie-tomaty-zamechatelnoe-nasledie.htmlI also have one line that survived a 22°F freeze in 2007. I lost about 5000 plants, but 4 or 5 plants of a single variety survived. I grew 3 of them and saved seed to produce the line I call Tastiheart. Here is some more research showing that cold tolerance genes exist in S. Habrochaites. I also have information about cold tolerance in S. Lycopersicoides which is native to high altitudes up to 3700 meters (2 miles high) in the Andes and is routinely subjected to temps of 0°F to 15°F. www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0050785I requested S. Lycopersicoides introgression lines from TGRC and should receive them this week. So my question Joseph, would you be interested in trialing some presumed cold tolerant varieties but with the stipulation that you have to apply some scientific rigor to keep track of exactly which variety is most cold tolerant? In other words, details! Details! DarJones |
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Post by Joseph Lofthouse on Dec 17, 2012 16:28:46 GMT -5
So my question Joseph, would you be interested in trialing some presumed cold tolerant varieties but with the stipulation that you have to apply some scientific rigor to keep track of exactly which variety is most cold tolerant? In other words, details! Details! DarJones: Good work! You're killing me... Such a tease. By nature, I am incredibly anal. I compensate by pretending like I am happy go lucky. And I usually manage to convincingly pull-off the happy-go-lucky routine. Except those that know me best, have come to recognize a certain sigh/yawn that signals that the underlying anality is still there. (It's not evident in written communication though.  ) It seems like you are doing very important work, and I'd really like to participate, so here is my resume. I worked in a chemistry lab doing analytical analysis for 20 years, so I possess the skills to keep detailed records. I known how to make labels that will last the whole growing season, and to make backup maps so that even if a kid pulls out the stake that I can still tell which is what. My popcorn and squash seeds are currently stored and labeled fruit-to-packet with the mother's name, and in some cases with grandmother's name as well. [Woo Hoo! Me keeping a pedigree? Please don't rat me out, I've got my cavalier reputation to maintain.] For collaborating evidence, consider the phollowing photos, of my garlic trials, which I took a few minutes ago in my garden.
I have set aside approximately 1/4 acre this summer for plant breeding experiments that have no production quota associated with them, so I have plenty of space to conduct frost/cold tolerant tomato trials.
And most importantly, I promise to make labels and keep detailed records.
So if I've persuaded you to take the risk on me, let's collaborate further on what the trial protocols should be, etc. |
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Post by DarJones on Dec 17, 2012 19:17:35 GMT -5
The obvious end of the day requirement is to grow tomatoes that produce a crop even when challenged with cold temps and a very short season. The means to that end is to find genetics that will lead to significant improvement of tomato production in a temperate climate. So here goes with my thoughts so far.
Tomatoes are a tropical plant. Their origin was in the Peruvian Andes from the equator to 10 degrees South latitude. Their extended native range including wild species is from 20 degrees South latitude to 30 degrees North latitude. Note however that domestication appears to have occurred between 20 and 30 degrees North in the Central America region and seems to date to about 5000 BCE. These are approximate numbers just to get a sense of the issues to deal with. The key fact here is that they originated in the tropics and therefore are not highly adapted to temperate climates.
Tomatoes are closest related to non-tuber bearing potato species, more distantly to tuber forming potatoes, and still further distant to peppers in the capsicum genus. Including Solanum lycopersicum, there are currently 13 species recognized in Solanum section Lycopersicon. Three of these species - S. Cheesmaniae, S. Galapagense, and S. Pimpinellifolium - are fully cross compatible with domestic tomato, four more species - S. chmielewskii, S. habrochaites, S. neorickii, and S. pennelli - can be readily crossed with domestic tomato though with some limitations, and five species - S. arcanum, S. chilense, S. corneliomulleri, S. huaylasense, and S. peruvianum - can be crossed with domestic tomato with significant difficulty usually requiring embryo rescue to produce viable plants.
Solanum section Lycopersicoides and section Juglandifolium are represented by two species each that are considered bridge species genetically intermediate between tomato and non-tuber bearing potato species. S. Lycopersicoides can be crossed with domestic tomato and introgression lines have been developed. This species was significant in moving the domestic tomato from separate genus status into the Solanum group because it directly links the tomato into the potato family.
The factors I've dug out so far include that the cold response pathway is especially weak in tomato. The roots are inefficient at absorbing potassium and phosphorus at low temps. Growth stops and the leaves show yellowing and chlorosis at temps below 45°F. Frost is a significant stressor because it can damage leaves at temps of 35°F and below. Frost forms as moisture condenses onto the protein coats of bacteria that live on the leaf surfaces. At about 28°F the leaves freeze. Below 28 degrees, very few plants survive.
There are some selected varieties with significant cold tolerance. These include lines with the ft gene which enables setting fruit at 40°F. This gene is in LA2006 which I have seed for. Several Russian selections have significant cold tolerance which has been determined by plants surviving overnight freezes down to 8°F. Lines such as Wheatley's Frost Resistant, Siberian, and Glacier have been selected in the U.S. These have varying claims from tolerance to early season cold to late season tolerance of below freezing temps.
I will have about 20 varieties with various levels of known cold tolerance to test. I would like to send you several seed of each so you can grow them in parallel with my growout. I plan to have them in the ground the first of March which is about 40 days too early in my climate. The probability of one or more severe freezes is near 100%. I plan to have a section of floating row cover to put over the plants so frost will not form directly on the leaves. Otherwise, they will be left to fend for themselves. I know that your climate is much more abrupt than mine, but would request that you take a similar approach by setting plants out as early as possible into cold soil to see if they can survive. Any plants that survive, save seed, and sell fruit if you have a surplus.
I haven't decided how to handle the introgression lines from S. Lycopersicoides yet. I have about 40 of them coverning 95% of the genome. The thing is that many of them will have serious problems and may not be able to make fruit or will be incapable of surviving unless grafted onto a compatible hardy rootstock. I am hoping to identify a few chromosome segments that significantly impact cold tolerance. S. Lycopersicoides is probably the most cold tolerant wild species that can be crossed with tomato. It is so far distant genetically that it is very difficult to move genes across to tomato chromosomes. I will send you a few of the breeding lines from TGRC because it makes sense for you to trial some of them in parallel with me but these may be other lines with much more promise in terms of producing edible fruit.
Breeding objectives that seem to be viable include: Thicker leaves with a thicker surface layer of cells, leaves that retain efficiency and produce chlorophyll at low temps, stronger roots that are more efficient at absorbing soil nutrients, plants that produce natural sugars that slow freezing, plants that can survive late fall frosts and still mature good flavored fruit, and up-regulation of the cold response biopath.
I'll work on this some more over the next few weeks.
DarJones - who notes that a well baited hook catches fish!
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Post by Joseph Lofthouse on Dec 17, 2012 20:47:41 GMT -5
In my garden, with clear night-time skies, I routinely get radiant freezes on tomatoes when the air temperature (5 feet above ground level) gets down to 36F, and sometimes the leaves will get freeze damage at up to 40F. These freezes often occur without the formation of dew/frost, so I guess that would mean direct freezing of the plant tissue. Because these are radiant freezes, and not air temperature freezes, it's very common that the only leaves that freeze are those that are facing most directly towards space. So interior leaves don't freeze, and leaves that are flat-face to the horizon don't freeze, just those that are facing towards the sky. Wouldn't it be interesting if one of the plants that comes out of this project had a mechanism like sunflowers which follow the sun, only in this case, tomatoes that moved their leaves at night to face the horizon. Or how about fuzzy leaves that would shade the surface of the leaf from radiant cooling. My target date for planting tomatoes is June 5th. My average last frost date is about 10 days before that. In the 2012 growing season the last frost occurred on the summer solstice (June 20th). The first fall frost usually falls between the 5th and 20th of September. Here's what temperatures and cloud cover looked like during May 2012. The clear skies between the 5th and the 15th would have resulted in certain death for most of my current tomato cultivars, as would the freeze on May 28th.  Here is the data for June 2012. My tomatoes were planted into the field on June 2nd. The freezes between the 6th and the 13th killed perhaps 20% of the plants in the patch. They were replanted. The morning of June 20th we had thick frost, which didn't outright kill any plants, but damaged the outer leaves of some cultivars.  In the fall, there was one cultivar, which showed remarkable resistance to frost. It didn't ripen tomatoes for me, but there were probably some green ones that I could have collected. It sure grew lots of vines, but didn't set fruit early enough. I'll do some reading before spring about the closely related species. The earliest planting of sweet corn that survived last year was planted on April 17th (Three weeks earlier than customary for corn). |
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Post by Joseph Lofthouse on Dec 17, 2012 21:33:46 GMT -5
The 130-140 DTM of that last one doesn't stand a chance in my garden. The first one listed as 90 days from germination has a good chance in my garden. |
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Post by atash on Dec 18, 2012 1:04:03 GMT -5
Wow, good work DarJones.
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Post by raymondo on Dec 18, 2012 3:43:03 GMT -5
A great project. I'll follow with interest.
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Post by DarJones on Dec 18, 2012 4:02:07 GMT -5
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Post by davida on Dec 18, 2012 10:08:59 GMT -5
Great work, Dar. I'll be interested to see how they perform in the first year in Joseph's garden compared to Joseph's earliest tomato that is adapted to his garden.
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Post by 12540dumont on Dec 19, 2012 13:18:31 GMT -5
Joseph, I guess you have your work cut out for you. You should be careful with Dar...he's been known to land a few big 'uns. I have this hook that I can't seem to get out of my mouth.....And by the way, anyone who's ever received a seed from Joseph knows that his labels come typed! So yeah, happy-go-lucky, maybe, skip-and go naked perhaps, but never unorganized in the garden.
On the tomatoes that are too long for your season, any chance that you can start them early and keep pruning and potting up? Or is that cheating the whole point of getting frost resistant quick tomatoes?
Terrific project.
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Post by Joseph Lofthouse on Dec 19, 2012 13:37:36 GMT -5
I frequently buy and plant huge tomato plants in 2 gallon pots from the nursery... Figuring that they will give me a quick early harvest. They don't produce significantly earlier or better than my homegrown plants that are transplanted into the garden as 6 week old seedlings. The nursery plants are generic generally adapted varieties that have not been selected to thrive under local conditions. If I had the ability to grow out my own tomatoes to that size, and could plant cultivars that are known to me to do well, then it might be useful. I've had a greenhouse sitting in the garage for years, just waiting to be put together....
I get the most boost to production by planting tomatoes on the south side of a building. I guess it creates a slightly warmer micro-climate.
I suspect that setting fruit at lower night-time temperatures may be more important to me than frost tolerance: Because I have gotten pretty good at predicting when the last killing frost will occur. That can mostly be avoided. And there are not all that many growing degree days available in May. But it would be nice if the roots could get established during May, so that when it finally warms up that the tomatoes are eager to grow instead of suffering through transplant shock.
I used to draw pictures of long-necked-butternuts on seed packets... I got teased about that, so now it's typed labels.
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Post by keen101 (Biolumo / Andrew B.) on Dec 19, 2012 14:49:13 GMT -5
I've had a greenhouse sitting in the garage for years, just waiting to be put together.... Joseph, if you've got a greenhouse to play with, then I’d say save it for something harder to work with like teosinte. If the teosinte here had a head start here last season it might have just made it to mature seeds. I had a few green seeds just starting to mature when the frost hit. I suspect if one can extend the season just long enough while exposing the plants to the natural climate as much as possible that the epigentics will be imprinted with the average temperature and season length that they will be slightly easier to grow the next year. If this can be done for a few seasons, then they might be able to be grown normally without something like a greenhouse. |
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Post by adamus on Dec 21, 2012 0:48:10 GMT -5
Ahh, so this is what happens when an obsessive compulsive meets an anal retentive. Good tomatoes.Yay. !!!!! ;D
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Post by DarJones on Dec 21, 2012 22:24:42 GMT -5
The only logical conclusion is that an infinite amount of energy will be released.  Joseph, I have about half of the breeding lines but am waiting for the stuff from Russia. I will let you know when it gets here. DarJones |
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Post by DarJones on Dec 28, 2012 22:50:12 GMT -5
I added 3 more links to the reading post. These three are highly significant for cold tolerance. In particular, I am requesting PI 120256 from ARS-GRIN. I also have several S. Habrochaites introgression lines that have been documented for cold tolerance as per the linked articles. The most significant genes for cold tolerance appear to reside on chromosomes 6, 7, 9, 11, and 12. LA3969 with a chromosome 12 segment appears to have at least 5 genes that are highly associated with cold tolerance. The highest levels of cold tolerance present in S. Lycopersicum do not even come close to the levels that are present in the wild species. note for Joseph, long neck butternut drawings on seed packages would surely get you a laugh around here. I suggest continuing with the printed labels. DarJones |
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) It seems like you are doing very important work, and I'd really like to participate, so here is my resume.
