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Post by templeton on Apr 21, 2016 21:57:10 GMT -5
A couple of seasons ago I crossed a semi-leafless field pea (kaspa) with my yellow snow (Pixie Moon, a sib line to Joni's Taxi), inspired by a post from the Mudflower blog (I've done a bit of trading with Damien) about making peas easier to see and harvest. One of the winter-grown F2s from that cross yielded a dwarf semi-leafless yellow (all recessive traits, so easy to stabilise), but rather than wait for the pods to develop to test for fiber, as luck would have it, I had a flowering yellow snow ready, so did an F2 backcross to the yellow snow. I grew out the F1 BX (back cross) this summer, and last month sprouted the F2 BX. Both dwarf and hypertendril show up early in the seedling stage, so I grew the seedlings out in little jiffy pots, so I could check before planting out. I got one hyper+dwarf, so as a bit of insurance, sowed another dozen or so seeds. This is yielding some good stuff, and the hypertendril trait is coming through. Here a pic of the dwarf, hyper, which WILL be yellow, and with luck, should also have the low fiber genes, giving a snow. This season I've got smart, and am growing a set of most of the snows in my collection, giving the possibility of extra back crosses if needed.  T |
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Post by farmermike on Apr 21, 2016 23:58:08 GMT -5
Inspiring work, templeton! How can you recognize the dwarf trait so early in the seedling stage?
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Post by philagardener on Apr 22, 2016 5:32:12 GMT -5
In my experience, normal height seedlings literally stand out from the dwarfs within a week of showing above ground.  |
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Post by templeton on Apr 22, 2016 20:16:44 GMT -5
Inspiring work, templeton! How can you recognize the dwarf trait so early in the seedling stage? As phila says, the dwarfs have short internode length (the stem length between leaf sets), so once they get a couple of sets of true leaves, you can usually discern the dwarfs. Occasionally you get a tall that starts off a bit shortish, but usually its fairly clear. There are a few different genes that determine internode length, and when these double up you get very short internodes. I'll try and find some shots to post. T |
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Post by diane on Apr 23, 2016 10:43:14 GMT -5
Short internodes sound ideal. I sowed many snows and snaps in the greenhouse so I could cross them. They have started to flower, but they're
2.5 metres tall, so the flowers are well above my head. I guess I'll need to use a stepladder for the crossing.
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Post by templeton on Apr 23, 2016 21:55:32 GMT -5
A few pics of internode length, the shortest a yellow snow project - Ray's Golden Spring = Golden Podded X Oregon Spring that raymondo grew out for me a few years ago as part of a not very successful cooperative coloured snow project, a medium=semi-dwarf internode, and a long internode both from my red snow project    |
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Post by keen101 (Biolumo / Andrew B.) on Apr 25, 2016 11:36:23 GMT -5
Inspiring work, templeton! How can you recognize the dwarf trait so early in the seedling stage? Rebsie's video shows how apparent the difference between tall and dwarf internodes are even in the seedling stage. It even seems possible to identify heterozygous offspring which are half dwarf and half tall as there seems to also be a height difference between them and the tall ones. www.dailymotion.com/video/xcwxai_introduction-to-luna-trick-pea_tech..If mendel was the father of genetics and pea breeding, then surely rebsie is the mother of pea breeding as i think she has inspired a whole new generation of pea breeders. Interesting that she said she was inspired by carol deppe. |
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Post by steve1 on Apr 25, 2016 16:47:17 GMT -5
keen101 (Biolumo / Andrew B.) Interesting about the intermediate offspring. There are I think at least 5 recognized genes that only function in the presence of le. I seemed to have three different heights segregating in one cross - I just assumed I had one of the other genes in the mix. I suppose you could always check the numbers and run it through a chi square.
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Post by keen101 (Biolumo / Andrew B.) on Apr 25, 2016 19:04:30 GMT -5
Yeah, i wasn't aware that there were 5 genes that could be responsible for height. But often i suspect that it's not just a case of a simple recessive dominance kind of deal. In the case of some dwarf x tall crosses i suspect that sometimes it's closer to co-dominant. But your right, actually crunching the numbers should shed some light whatever the case may be. If it's as simple as what i'm suggesting then technically you should get about 1/4 tall, 1/4 dwarf, and 2/4 intermediate. But if the numbers are different, then perhaps your right and there are other genes at play.
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Post by keen101 (Biolumo / Andrew B.) on Apr 27, 2016 23:15:24 GMT -5
keen101 (Biolumo / Andrew B.) Interesting about the intermediate offspring. There are I think at least 5 recognized genes that only function in the presence of le. I seemed to have three different heights segregating in one cross - I just assumed I had one of the other genes in the mix. I suppose you could always check the numbers and run it through a chi square. Steve, another alternate explanation is that assuming you had a perfect mendelian trait of tall vs dwarf that in addition you were also observing hybrid vigor which may actually be taller than the homozygous tall plants. However i'm not sure whether hybrid vigor sticks around in heterozygous F2 plants or not. According to Breeding and the Mendelian Discovery by A.D. Darbishire, he say's this on page 163: |
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Post by steve1 on Apr 28, 2016 1:02:09 GMT -5
Does that mean then the intermediates are pure breeding tall and the tallest are heterozygous? When they hit full size count them up - and if you want I'll run them through a chi square stats package. I think F2's are pretty vigorous from what I've seen - but I believe it's related to overall heterozygosity not just the Le/le locus.
Cheers
Steve
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Post by keen101 (Biolumo / Andrew B.) on Apr 28, 2016 10:22:39 GMT -5
Does that mean then the intermediates are pure breeding tall and the tallest are heterozygous? When they hit full size count them up - and if you want I'll run them through a chi square stats package. I think F2's are pretty vigorous from what I've seen - but I believe it's related to overall heterozygosity not just the Le/le locus. Cheers Steve From what i understand it's at least a possibility. Without genetic testing i'm not sure how you actually find out unless you do lots of measurements and follow the offspring closely. Perhaps if you measured the pure tall parent line as a control base line you could figure it out. But i think your right, hybrid vigour may be related to the overall genetic heterozygosity and not just for one locus. |
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Post by keen101 (Biolumo / Andrew B.) on Dec 31, 2016 17:24:14 GMT -5
Any update T? Any nice photos? I getting ansy for spring.
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Post by templeton on Jan 1, 2017 16:04:33 GMT -5
Any update T? Any nice photos? I getting ansy for spring. , I'm flat out in the forest 9 hours a day at the moment gathering data for my PhD, so the garden is neglected. The peas are sitting there waiting for a window for me to get out and assess them - hot weather later this week means i'll probably have a day or so off to find the camera and do some assessment - if i can sneak away from my burgeoning domestic commitments. Thanks for your interest. T |
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