Author Topic: Beginnings of a wheat landrace  (Read 412 times)

Kai Duby

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Re: Beginnings of a wheat landrace
« Reply #15 on: 2019-01-13, 08:43:48 PM »
As far as I have been able to find Khorasan wheat is actually a subspecies of Durum (Triticum turgidum subsp. turanicum) as is Polish wheat and Sin et Pheel (T. turgidum subsp. polonicum). The durums are apparently tetraploids while common wheat (T. aestivum) is a hexaploid. I don't know how this effects their ability to hybridize.

I enjoy the taste of Khorasan wheat so much and use it in a different way that I'm aiming to keep it separate from the common wheat mix. So I am planning on making multiple groups or psuedo-populations for specific traits and species.

- T. turgidum: likely a mix of the less common forms like khorasan, polish and persian. Mainly for large grains suitable for soups and pasta. This whole species interests me because I don't seem to have a problem digesting the less common "ancient" grains whereas most pastas and semolina flours give me quite the gut grief.

- Common Awned Spring Wheats

- Common Awnless Spring Wheats: I think the awnless quality is important enough to warrant a separate group because I intend on keeping animals one day that I'll feed some wheat hay to and hand harvesting awnless wheat seems to be a more enjoyable experience.

- Common Winter Wheats

I certainly intend on trialing the other species of wheat at some point but for my own purposes the "hulless" species and varieties are more appealing.
I think it would also be a worthwhile venture to accumulate the wheat ancestors and have a working population that represents all wheat diversity like the mountain maize populations interplanted with teosinte.
San Luis Valley, CO. >7,500'. Zone3-4. Low rainfall: 8-10''. Low Humidity. High winds.

Walt

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Re: Beginnings of a wheat landrace
« Reply #16 on: 2019-01-14, 02:15:06 PM »
Tetraploid T. turgidum and hexaploid T. aestivum cross without much difficulty.  Bear in  mind that must bloom together, as grass pollen in general doesn't keep.  Under hot dry conditions, the pollen may be good for only a few minuts.
T. turgidum is AABB, T. aestivum is AABBDD.  The hybrid. AABBD has enough chromosome pairing to give some fertility.  The pollen grains (from the hybrid) that do the pollinations will be those with either AB or ABD.  Pollen grains with incomeplete sets of D will not compete with those with complete sets or no sets of D.
So the F2 will have many aneuploids, but in each generation, the number of aneuploids will be reduced by about half.  You will soon have a population with a mixture of mostly T. turgidum and T. aestivum.  But there will have been gene exchange between the 2 species.

Kai Duby

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Re: Beginnings of a wheat landrace
« Reply #17 on: 2019-01-26, 08:01:02 PM »
Walt: Thank you for the details! I did grow the Khorasan right next to the common wheat so I will certainly be on the look out for crosses. Do the aneuploids have any advantage or disadvantage over the other ploidy levels? Would an ongoing population of the two have varying cross pollination every year so the aneuploid count would be annually rejuvenated despite decreasing annually from poor fertility?
San Luis Valley, CO. >7,500'. Zone3-4. Low rainfall: 8-10''. Low Humidity. High winds.

Walt

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Re: Beginnings of a wheat landrace
« Reply #18 on: 2019-01-28, 10:06:53 AM »
Remember  that wheat is mostly self pollinating.  And crosses can only happen if the 2 plants bloom the same day.  If the plants are in bloom together and close together, you could get crosses.
The only use of aneuploids so far has been to keep a gene for insect or disease resistance in a breeding line while backcrossing to a commercial variety to get the commercial variety back to "pure" other than the spare chromosome, then hit it with radiation to break up the spare chromosome and get the gene onto a chromosome of the commercial variety.
Presumably the aneuploids could be used for other things but such uses don't come to my mind. 
I only see them as an intermediate step in getting gene exchange between the AABB chromosomes of the two species.  Rarely, a D chromosome will pair with an A or B chromosome and exchange genes.
The aneupoloids themsevles are viable but have reduced vigor compared with the euploids.
Once there are hybrids between the species, the hybrids will be closer in bloom time to the species and new hybrids will become more common.
But if I wanted to mix the genes, I'd hand pollinate a few heads and grow the hybrids as a new population.  But  that's just my preference.  To each his own.