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Post by steve1 on Apr 1, 2016 22:43:56 GMT -5
keen101 (Biolumo / Andrew B.) - the constricted pod phenotype as related to Mendels work relates to a single recessive gene (though as his papers were lost they have not been able to work out whether it was pp or vv). In the 1860's the single recessive was the standard snow gene type and it wasn't I believe to about 1925 (Wellensiek), the no parchment ppvv genotype was recognized from a cross. I'd have to say from my testing the very small amounts of parchment seen in some of the single recessive genotypes would likely make no discernible difference to edibility. I will post a few more stain pics in the thread I have posted previously.
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Post by keen101 (Biolumo / Andrew B.) on Apr 1, 2016 23:43:28 GMT -5
keen101 (Biolumo / Andrew B.) - the constricted pod phenotype as related to Mendels work relates to a single recessive gene (though as his papers were lost they have not been able to work out whether it was pp or vv). In the 1860's the single recessive was the standard snow gene type and it wasn't I believe to about 1925 (Wellensiek), the no parchment ppvv genotype was recognized from a cross. I'd have to say from my testing the very small amounts of parchment seen in some of the single recessive genotypes would likely make no discernible difference to edibility. I will post a few more stain pics in the thread I have posted previously. Thanks Steve, I'm not exactly sure what all that means. Are you saying that you can get a constricted pod that is not low in fibre? If so, that's somewhat interesting. Whether the pp or vv genes are involved or not i'm aware of very few pea varieties that have constricted pods. One might be Carouby De Massane, but i believe i've seen inflated versions too. I'm not really sure whether a snow pea with constricted pods or inflated pods are more advantageous than the other. Perhaps just personal preference? In a big pod like Carouby de Massane i suspect inflated pods make more of an impression than constricted, but i have no idea if that affects fiber or edibility characteristics. |
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Post by steve1 on Apr 2, 2016 6:16:13 GMT -5
Sorry keen101 (Biolumo / Andrew B.) - not sure I explained myself very well. The whole constricted pod that Mendel used as one of his 7 traits was related to dry pod. If you don't get a constricted hugging the contours of the seed dry pod phenotype there should be neither of the recessive pp or vv genes present or in other words a full parchment shelling pea. By definition that is. I have struck one (so called) snow pea that developed parchment late, by none the less was full parchment shelling pea (with inflated dry pod). Mind you it was good to eat young. From my reading the PPvv genotype can have a complete thin layer of parchment (on the most extreme examples) but generally is just patches although in some cases can be very difficult to tell from non parchmented peas - from Rasmusson 1927 who wrote the stain phenotype/genotype paper. Same I would say with the ppVV genotype, some of the examples I've stained are so low in parchment (visually) you'd be extremely hard pressed to notice the difference between that genotype and a non parchmented ppvv genotype visually and on the tooth. When you next have a few very mature fresh pods (mature seed but not senescent) of Carouby split the pod in half length ways and snap the half pod out wards to inwards. I would expect pods that had a distinct peelable layer of parchment would dry as inflated pod type and and be genotype PPVV. Not that it matters if parchment is produced late and you use the peas early! More important if you are trying to breed snow/snap peas that are completely edible as mature pods. Hope that helps. |
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Post by reed on Apr 2, 2016 10:02:58 GMT -5
I also agree that Sugar Magnolia is a very decently flavoured purple podded snap pea. Amish Snap is such an excellent snap pea that I have looked no further amongst the snap peas. Ha Ha Ha, I hit the jackpot. Those two kinds are growing in my garden at this very minute, thanks to you ferdzy. Gonna be a fight here I'm afraid when someone finds out that other than a little taste they for for seed increase, not eating. Supposed to be a couple cold nights on the way. Are the seedlings good and frost tolerant? |
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Post by keen101 (Biolumo / Andrew B.) on Apr 2, 2016 10:47:20 GMT -5
Honestly i still don't know if i fully understand it. I don't think it was your explanation steve, i think it's just my brain isn't ready for such a concept. In any case i hope to evaluate my pods for fiber and strings better this year. Perhaps i can identify some good lines that i should use for breeding. Sometimes the best way to learn about something is just by doing. Some things just cant be explained they have to be seen and felt and experienced. edit: steve1, i think i've seen you mention the parchment staining before in your thread. Can you resurrect that thread and show us more. What chemicals do you use for the staining? Are there cheap easily obtainable chemicals which would do the same job? I know in biology labs they use a blue staining technique for microscope slides, i assume that's what you are using. Would iodine work? I know it stains starch, so i assume not. |
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Post by ferdzy on Apr 2, 2016 17:29:49 GMT -5
reed, I think they are reasonably frost tolerant. I can't say I plant either of those super early so I have never really tested them. My philosophy is to put some short DTM peas (Strike, Norli) in as soon as possible and then mid season/late peas have less pressure on to go in, since they are not being relied upon to supply the first peas but to continue the season. I can tell you that Amish Snap are typical of peas, in that I never got the 6 weeks of production everyone quotes for them, until we finally had a cool, damp summer and then they just kept going and going and going. A note for diane; peas without parchment in the pods also tend to have leaves without tough stringy fibres, making them better for use as a leafy green. I also have to comment that around here people always seem to want to grow pea sprouts, which are just not that great in my experience. Far better is what the Chinese call "dau miu" (means pea shoots, I'm pretty sure) which are the pinched off tips - 2" to 3" - of the growing vines of young plants. These are both more substantial and less stringy than pea sprouts as the microgreen crowd knows them. Last I saw them for sale - a good few years back since the area I am now in is not, uh, cosmopolitan - they were $16.00/lb. I bet they are $20 now or close to it. I have never understood why local farmers aren't churning them out. At any rate, it occurred to me that Agrohaitai would have something to say about them, and they do. www.agrohaitai.com/beanpea/snowpea/snowpea.htm
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Post by templeton on Apr 3, 2016 3:33:50 GMT -5
Honestly i still don't know if i fully understand it. I don't think it was your explanation steve, i think it's just my brain isn't ready for such a concept. In any case i hope to evaluate my pods for fiber and strings better this year. Perhaps i can identify some good lines that i should use for breeding. Sometimes the best way to learn about something is just by doing. Some things just cant be explained they have to be seen and felt and experienced. edit: steve1, i think i've seen you mention the parchment staining before in your thread. Can you resurrect that thread and show us more. What chemicals do you use for the staining? Are there cheap easily obtainable chemicals which would do the same job? I know in biology labs they use a blue staining technique for microscope slides, i assume that's what you are using. Would iodine work? I know it stains starch, so i assume not. Hi Keen. Classically there are two fibre genes. In a nice well-organised world (the sort of world steev will bring about when he becomes world-president-for-life) every nice-eating peapod would be genotype ppvv. But of course, things aren't quite that simple. The important phenotype is 'tastes nice without fibre when i eat it'. A ppvv pea should be just that, and a way to test for it is to look for constricted dried pods - no fibre to keep the pod all stiff as it dries. ( Joseph Lofthouse's crushable dried pod test probably also tests for this.) But there are other genetics that delay pod fibre production - it is possible to get a 'nice to eat' phenotype in sub-mature pods, even if they have P or V, since they have delayed fibre production, controlled by other as yet undocumented genetics. If you want to grow 'filled pod' mange touts, like snap peas and the way Carol Deppe uses Oregon Giant as a filled pod mange tout, then you probably need ppvv - unless of course there are some 'very delayed fibre' genetics around - but who knows? Since we know about pp and vv, as a breeder these are good targets to have in your parents, but it is possible that 'nice to eat' varieties might have only pp or vv, with the other genetics that make them palatable. Since we don't know what these are, it makes choosing breeding parents problematic. I suspect that there might be genes to delay string production too. Since the stringless gene seems to be linked to lack of vigor, searching for a 'string delay' phenotype might be smarter. And we haven't even started on 'sugar in pod tissue' discussions - I'm sure there are genetics that control the flavour of the pods, as distinct from the flavour of the included peas, since I've tasted both blah and yum flavours in my young pods way before the peas themselves have swollen. Hope I haven't confused matters... T |
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Post by reed on Apr 3, 2016 7:45:42 GMT -5
reed , I think they are reasonably frost tolerant. 24 F this morning and they look fine so far, have to wait till the sun is up on them good to know for sure but I'd say they are frost tolerant. |
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Post by steve1 on Apr 3, 2016 16:57:15 GMT -5
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Post by diane on Apr 3, 2016 20:26:40 GMT -5
Usually if I eat pea shoots, I cut off the end of the stems with leaves, and they are delicious.
I don't have any at that stage of growth now - I have the ones I'm going to hybridize, and they are starting to produce buds, so
I don't want to chop off the tips. Instead, I sampled a leaf from each. None was inspiring. Maybe it is the juicy stems that
taste good, not the leaves.
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Post by steev on Apr 3, 2016 22:05:55 GMT -5
I snip my Austrian field peas for salad, only what snips easily with my thumbnail (so low-tech); given the time to snip a pound and the mark-up a produce market would want, in view of freshness/wastage issues, $20 per pound wouldn't surprise me at all.
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Post by raymondo on Apr 12, 2016 4:22:56 GMT -5
...Far better is what the Chinese call "dau miu" (means pea shoots, I'm pretty sure) which are the pinched off tips - 2" to 3" - of the growing vines of young plants... I heartily agree. Love them in salads and stir fries. |
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Post by keen101 (Biolumo / Andrew B.) on Dec 27, 2016 1:18:04 GMT -5
Hi Keen. Classically there are two fibre genes. In a nice well-organised world (the sort of world steev will bring about when he becomes world-president-for-life) every nice-eating peapod would be genotype ppvv. But of course, things aren't quite that simple. The important phenotype is 'tastes nice without fibre when i eat it'. A ppvv pea should be just that, and a way to test for it is to look for constricted dried pods - no fibre to keep the pod all stiff as it dries. ( Joseph Lofthouse 's crushable dried pod test probably also tests for this.) But there are other genetics that delay pod fibre production - it is possible to get a 'nice to eat' phenotype in sub-mature pods, even if they have P or V, since they have delayed fibre production, controlled by other as yet undocumented genetics. If you want to grow 'filled pod' mange touts, like snap peas and the way Carol Deppe uses Oregon Giant as a filled pod mange tout, then you probably need ppvv - unless of course there are some 'very delayed fibre' genetics around - but who knows?
Since we know about pp and vv, as a breeder these are good targets to have in your parents, but it is possible that 'nice to eat' varieties might have only pp or vv, with the other genetics that make them palatable. Since we don't know what these are, it makes choosing breeding parents problematic.I suspect that there might be genes to delay string production too. Since the stringless gene seems to be linked to lack of vigor, searching for a 'string delay' phenotype might be smarter. And we haven't even started on 'sugar in pod tissue' discussions - I'm sure there are genetics that control the flavour of the pods, as distinct from the flavour of the included peas, since I've tasted both blah and yum flavours in my young pods way before the peas themselves have swollen. Hope I haven't confused matters... T It is possible to get too hung up on the genetics, and lose sight of the intended outcome, which is edibility. Does it really matter if a snow pea has late fiber or no fiber if at the picking stage it is delectable? From a breeding sense it does, but from the food production perspective it doesn't matter that much. Not that I'm going to stop pursuing ppvv.T - I agree entirely, the end game is taste. However I found the genetics interesting enough to post mostly for those thinking about using that variety as part of a red pod project. The genotype may help some eradicate a recessive from their project and knowledge of the late fiber formation adds increased complexity (in that I can't say how it is inherited because I can't say whether it is mono or polygenic in nature or dominant or recessive). It's also interesting I'm starting to think there are not that many ppvv varieties available. Cheers Steve So today i was curious if fasciated (aka. umbel-type peas) were the same trait as Mendel's "axial" trait. While reading this cool page from the JIC i found this little interesting tidbit about possible linkage in genes. I will quote it below. www.ncbi.nlm.nih.gov/pmc/articles/PMC3176118/levrgpSo, what i gather from this is that if you are looking for the vv phenotype you are most likely to find it in dwarf peas? And that you may find some linkage between yellow pods and wrinkled seeds (but not necessarily). If this is true this is very interesting. In the case of breeding for ppvv genotype parchment-less snap peas you should work with dwarf peas apparently. Thoughts? |
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Post by templeton on Dec 27, 2016 15:51:34 GMT -5
keen101 (Biolumo / Andrew B.), I don't know enough genetics to not make me look stupid when trying to explain the mechanics, but I'm pretty sure the linkage is between the genes whether they are are in the dominant or recessive mode. Perhaps someone with more knowledge will illuminate us. T
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Post by philagardener on Dec 27, 2016 19:35:51 GMT -5
Dominant / recessive refers to the interaction (in a diploid) between different alleles at a single locus in terms of the resulting phenotypic character.
Le (tall) and le (dwarf) are alleles at a height determining locus. Lele (heterozygous) diploids are tall, so tall is dominant to dwarf.
Similarly, V (inflated) and v (constricted) are alleles at a pod type locus. Vv diploids have inflated pods, so inflated is dominant to constricted.
Linkage means that alleles for different traits tend to be inherited together because they are physically connected ("linked") on a chromosome.
If the height determining locus (where Le or le is found) is linked to the pod shape locus (where V or v is found), then parental combinations of traits will tend to be inherited together and will show up among the offspring more frequently than predicted by Mendel's rule of independent assortment.
Non-parental combinations of those traits (recombinants) are generated through a process called crossing-over and involves a physical exchange of DNA between homologous chromosomes in meiosis. The frequency of recombination depends on the distance between the loci that are being studied.
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