Sunroot and Sunflower Crosses

[starry]

Some info on crosses that have been done with sunroot and various sunflower species.

bulbnrose.x10.mx/Heredity/sunflowerXchoke/sunflowerXchoke.html

Would be great if it were possible to create a sunroot with large edible seeds...or even just a perennial sunflower with large edible seeds.

[nicolas]

I'm not sure to understand but it seems a dead end cause a cross H. tuberosus x H. annuus is weakly fertile and the F2 is infertile ? (see above)

Hybridization experiments showed that the group of rhizomatous species with a chromosome number equaling that of sunflower (2n = 34) did not cross at all with the sunflower, whereas the tuberous group with a chromosome number of 2n = 102 crossed relatively easily. H. subcanescens crosses particularly well with sunflower, and H. macrophyllus and H. tuberosus somewhat less easily. Crosses succeed if these species are used as seed parents, while sunflower used as seed parent has an adverse effect on the cross.

Form-creative process in hybridization of Jerusalem artichoke with sunflower. The first-generation hybrids are marked by a high variability in all morphological characters, particularly in stem branching, a cordate or ovate leaf shape, tuber formation or absence of it, anthocyanin coloring of the stem, etc.

Hybrid plants can be distinguished from non-hybrids already in the seedling stage by their cotyledons. In ordinary seed-grown Jerusalem artichoke these are dark green in color, more elongate, and without an abrupt transition to the petioles. The cotyledons of the hybrids are intermediate between those of Jerusalem artichoke and sunflower: they are wider, and their blades narrow abruptly where they join the petiole.

In hybrids between Jerusalem artichoke and sunflower the head is considerably larger than in Jerusalem artichoke, but smaller than in sunflower; it usually has a diameter of 4 to 5 cm, and 8 to 10 cm in only single specimens

The tuber-forming ability of Jerusalem artichoke X sunflower hybrids. Hybrids between Jerusalem artichoke and sunflower exhibit a varying tuber-formation ability. Together with high-yielding plants producing up to 4 kg of tubers each, there are others which only yield 100 to 200g. The tuber-formation character is dominant in F1 hybrids.

Only a small percentage (about 1%) of the large number of hybrid seedlings raised by us had an annual life cycle, i.e., the plants were without tubers and other perennial organs (stolons or root buds)

Characteristically, a certain percentage of plants grown from hybrid tubers do not form tubers themselves, though they do not differ from tuber-forming plants in any other way. Twenty-three of 470 plants raised from tubers, or 4.8%, were non-tuberous, and 14 plants, or 29%, formed perennial root buds, or small stolons without tuber thickenings in the collar region.

F1 hybrids have an intermediate vegetative period; most hybrids flower, but relatively few reach seed maturity.[in Ukraine]

The F2 hybrids from a backcross of F1 to sunflower or Jerusalem artichoke are completely sterile

F1 hybrids, too, have a high percentage of abortive pollen grains. The highest percentage was observed in the combination H. tuberosus x H. annuus (65.5)

[starry]

I guess I let my enthusiasm get ahead of my reading Interesting info anyhow.

[nicolas]

Hey me too, i was quoting in ecstasy until the lasts sentences. It is maybe not a dead end, but a one-shot breeding. One can still propagate the hybrid vegetatively, and maybe the F1 can produce offspring if self-pollinate ? So it is worth the try i think. One has to get a fertile sunchoke and a very big seeded sunflower and try crosses until the seeds of the hybrids are big. A medium sized seeded hybrid is still great for poultry i think, and the hybrid is interesting for fodder as noted in the article.

[agrorev]

Maybe creating an amphidiploid will restore fertility like the the Cucurbita and Phaseolus interspecific crosses?

[starry]

Feb 5, 2014 10:16:31 GMT -5 agrorev said:

Maybe creating an amphidiploid will restore fertility like the the Cucurbita and Phaseolus interspecific crosses?

Do you know how that is done? 

[oxbowfarm]

Colchicine?

[Graham]

You could also try to use a bridging species.

It would take some research to identify a suitable candidate, but it's always worth considering as a means to overcome incompatibility issues in wide crosses.

[starry]

A bridge species like another species of Helianthus?

[starry]

I have also found this image online but don't really understand what it is depicting nor could I find any supporting documentation other than the image.
Does anyone know what it means?



en.wikipedia.org/wiki/File:Annual%26perennial_sunflowerheads%26text.jpg

[Graham]

Yup.

One that's more compatible with your two target species than they are with each other. You would move the larger seed head from H. annuus into the bridging species then use your new hybrid to introduce the trait into H. tuberosus.

That's assuming a suitable species exists.

[starry]

Feb 5, 2014 13:20:28 GMT -5 starry said:

I have also found this image online but don't really understand what it is depicting nor could I find any supporting documentation other than the image.
Does anyone know what it means?

en.wikipedia.org/wiki/File:Annual%26perennial_sunflowerheads%26text.jpg

After staring at it for a bit I am assuming it is just showing that if you breed the various species together in the combinations shown you can get a population of hybrids that all have the same number of chromosomes?

[starry]

Blog posts of Sunroot x Sunflower from Mid-Atlantic Plant Research Center

maprc.blogspot.ca/2010/10/hopefully-jerusalem-artichoke-x-red-sun.html

maprc.blogspot.ca/2011/05/jerusalem-artichoke-x-red-sun-sunflower.html

maprc.blogspot.ca/2011/09/jerusalem-artichoke-x-red-sun-seedling.html

maprc.blogspot.ca/2012/07/helianthus-tuberosus-x-red-sun.html

maprc.blogspot.ca/2012/08/long-bloom-season-perennial-sunflower.html

maprc.blogspot.ca/2012/08/perennial-sunflower-still-going.html

maprc.blogspot.ca/2012/09/helianthus-hybrid.html

maprc.blogspot.ca/2013/08/gapland-gold-helianthus-hybrid.html

maprc.blogspot.ca/2013/09/sunflower.html

maprc.blogspot.ca/2013/10/another-try-for-some-red-in-perennial.html

[agrorev]

The backcross of the F1s to the tuberosus may be completely sterile, but the F1s are very diverse and can be crossed amongst themselves for multiple generations.  Doesn't seem like a dead end.  Is there an advantage to be able to back cross to the parent as opposed to crossing just among the F1s and their progeny?  I guess you might more easily influence certain characteristics.  The sterile tuberosus x (tuberosus x annuus) could be potentially useful as a clonally propagated crop as Graham says.  The article also mentions there was one individual of such a backcross that was highly fertile.  Another example that even in crosses that don't normally work well, there is the occasional combination that pairs well for whatever reason.

It seems the image confirms what the article says: you can create a diverse breeding group of tetraploid Helianthus hybrids when using tuberosus as the seed parent.

[nicolas]

Great news !