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Author Topic: Cherimoya/Pawpaw hybrid  (Read 12615 times)

usirius

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Re: Cherimoya/Pawpaw hybrid
« Reply #100 on: September 05, 2020, 02:17:07 AM »
keep us posted
Yes I will share any news here. Soon I will harvest the first Pawpaw fruit which flower has polinated with Cherimoya pollen. From this fruit and fromthe seeds I will share pictures.

Is there a way to genetically test the leaf? Maybe some university nearby that has something that could count the chromosomes?
Certainly there are institutes and universities here that could carry out a genetic analysis. Years ago, I wanted to have one done on a very interesting Vitis hybrid, which I created by open pollination, and I have contacted several institutions. Most of them refused, because they are busy with their own work, and the few who would have done it, demanded unreasonably much money. So I prefer to wait until I can see from other characteristics whether I have achieved hybrids or not. And if it worked, the chromosome set has to be doubled, because of the different chromosome sets of Cherimoya and Pawpaw.

This is super exciting stuff. Thank you for doing this experiment.
Thank you - you are welcome! I have to admit, it is also fun and all objections, comments and suggestions are inspiring and absolutely valuable for the evaluation and further development of this experiment!

That delay in fruit-set development is very interesting!

I don't recall having observed that.

I did sometimes observe the opposite, where foreign pollinations would be rejected so fast that there seemed to be an allergic reaction.
Interesting is also your observation and I think this does not contradict my observation, because the majority of Cherimoya flowers pollinated with Pawpaw pollen reacts in principle as u wrote, a very short time passes, mostly even shorter than if the flowers had not been pollinated, and the flower dries up and dies, The death of the flower is different and may give an indication whether perhaps genetic processes have already started or not. Some flowers dry out very quickly and evenly, i.e. petals and base of fruit, and some flowers first let the three petals dry out - like a dry mummy, which often remains loose at the base of fruit - and then dry out later with a little delay.


« Last Edit: September 05, 2020, 02:18:42 AM by usirius »
„May your choices reflect your hopes, not your fears.“ N. Mandela

Guanabanus

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Re: Cherimoya/Pawpaw hybrid
« Reply #101 on: September 05, 2020, 01:17:08 PM »
Chromosome doubling can happen, but usually doesn't.  Colchicine can be used, theoretically at least, to cause chromosome doubling on a new branch of the hybrid plant.  I never tried this, I have not heard of anyone's having had any success doing that with Annona species or hybrids.

Another event that happens is that a new hybrid, made with parents having different numbers of chromosomes, can be like a mule, having an uneven number of chromosomes.  These usually cannot make viable offspring, so no good seeds from these hybrids' fruit.  Or, they can't fruit at all.  I made "mules" like that when I pollinated Guanabanus muricatus (Annona muricata) with pollen from Guanabanus coriaceus (Annona coriacea)--- two plants, never any fruits, no matter what I pollinated their many flowers with.
Har

usirius

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Re: Cherimoya/Pawpaw hybrid
« Reply #102 on: September 05, 2020, 04:11:18 PM »
@ Guanabanus
Very constructive and interesting - your report on the hybrid you made - thank you for this Information!.


Yes absolutely, a polyploid hybrid does not have to be fertile.

Also there are examples which show that polyploidy can help to get fertile plant  hybrids. The cereale hybrid Triticiale - a cross between wheat (Triticum aestivum L.) as the female and rye (Secale cereale L.) as the male partner (×Triticosecale or Triticosecale Wittmack) ) the chromosome sets were doubled by using colchicine in the seedlings to obtain fertile offspring. In other words, the doubling of the chromosome sets could only lead to reproductive ability. Triticiale offsprings are usually selsbstungen from Trticicale x Triticiale h itself would actually have the possibility to work with colhizin, but I have not yet worked with it. I would have to read in and study the method, then I could also use it on the Annonaceae.

At this point I like to remember to one of my last posts - to the presentation which takes a summary of

Haldan's rule and the hybridogenic speciation and postzygotic incompatibility. Haldane (1892-1964) was a British Indian geneticist.

https://www.kunz.hhu.de/fileadmin/redaktion/Fakultaeten/Mathematisch-Naturwissenschaftliche_Fakultaet/Biologie/Institute/weitere_und_ehemalige_Dozenten/Prof._Dr._Kunz/07_Haldane_hybridogene_Artbildung.ppt (Sorry that it is written in German language. But the pictures will help to explain.)

So in genetics everything is possible. From no result to infertility to the emergence of a separate species with differentiation by developing an incompatibility to backcrossing with the parents. In the plant kingdom the development of incompatible hybrids

At this point I would also like to refer to another interesting report and quote from it: I think some of you, you maybe anyway, I will already know, A. muricata is also mentioned, sorry not A. coriacea )

Polyploidy in Fruit Tree Crops of the Genus Annona (Annonaceae)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6378316/
https://www.researchgate.net/publication/331019625_Polyploidy_in_Fruit_Tree_Crops_of_the_Genus_Annona_Annonaceae/fulltext/5c6181d692851c48a9ca964d/Polyploidy-in-Fruit-Tree-Crops-of-the-Genus-Annona-Annonaceae.pdf
"Genome duplication or polyploidy is one of the main factors of speciation in plants. It is especially frequent in hybrids and very valuable in many crops. (...) Surprisingly, while the hybrid atemoya has been reported as diploid, flow cytometry analysis of a progeny obtained from an interspecific cross between A. cherimola and A. squamosa showed an unusual ploidy variability that was also confirmed karyotype analysis. hile the progeny from intraspecific crosses of A. cherimola showed polyploid genotypes that ranged from 2.5 to 33%, the hybrid atemoyas from the interspecific cross showed 35% of triploids from a total of 186 genotypes analyzed. With the aim of understanding the possible implications of the production of non-reduced gametes, pollen performance, pollen size and frequency distribution of pollen grains was quantified in the progeny of this cross and the parents. A large polymorphism in pollen grain size was found within the interspecific progeny with higher production of unreduced pollen in triploids (38%) than in diploids (29%). Moreover, using PCR amplification of selected microsatellite loci, while 13.7% of the pollen grains from the diploids showed two alleles, 41.28% of the grains from the triploids amplified two alleles and 5.63% showed up to three alleles. This suggests that the larger pollen grains could correspond to diploid and, in a lower frequency, to triploid pollen. Pollen performance was also affected with lower pollen germination in the hybrid triploids than in both diploid parents. The results confirm a higher percentage of polyploids in the interspecific cross, affecting pollen grain size and pollen performance. The occurrence of unreduced gametes in A. cherimola, A. squamosa and their interspecific progeny that may result in abnormalities of ploidy such as the triploids and tetraploids observed in this study, opens an interesting opportunity to study polyploidy in Annonaceae.
(...)
Polyploidy is believed to be a major mechanism of adaptation and speciation, recognized as a major force in evolution (Van de Peer et al., 2017) and very valuable for crop improvement (Udall and Wendel, 2006; Mason, 2016). Polyploidy is more common in plants than in animals. It is estimated that between 30 and 70% of extant flowering plant species are polyploids (...)"

More I will not paste here. The best is to study the complete report by yourself!

Bytheway...to my new hybridizations of this year there is again a small setback. One of the ovaries, which took weeks to show that pollination was successful, has now decided to dry out after some growth. Another one is still in good shape, I hope it stays that way. Last year, such an ovary grew into a strongly deformed fruit, which is another sign of an unusual way of embryo formation. Unfortunately this fruit dried up in centimeter size and still hangs on the tree like a mummy. I have pictures, but I do not want to overload this post!
« Last Edit: September 05, 2020, 04:13:06 PM by usirius »
„May your choices reflect your hopes, not your fears.“ N. Mandela

usirius

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Re: Cherimoya/Pawpaw hybrid
« Reply #103 on: September 05, 2020, 04:13:33 PM »
@ Guanabanus
Very constructive and interesting - your report on the hybrid you made - thank you for this Information.


Yes absolutely, a polyploid hybrid does not have to be fertile.

Also there are examples which show that polyploidy can help to get fertile plant  hybrids. The cereale hybrid Triticiale - a cross between wheat (Triticum aestivum L.) as the female and rye (Secale cereale L.) as the male partner (×Triticosecale or Triticosecale Wittmack) ) the chromosome sets were doubled by using colchicine in the seedlings to obtain fertile offspring. In other words, the doubling of the chromosome sets could only lead to reproductive ability. Triticiale offsprings are usually selsbstungen from Trticicale x Triticiale h itself would actually have the possibility to work with colhizin, but I have not yet worked with it. I would have to read in and study the method, then I could also use it on the Annonaceae.

At this point I like to remember to one of my last posts - to the presentation which takes a summary of

Haldan's rule and the hybridogenic speciation and postzygotic incompatibility. Haldane (1892-1964) was a British Indian geneticist.

https://www.kunz.hhu.de/fileadmin/redaktion/Fakultaeten/Mathematisch-Naturwissenschaftliche_Fakultaet/Biologie/Institute/weitere_und_ehemalige_Dozenten/Prof._Dr._Kunz/07_Haldane_hybridogene_Artbildung.ppt (Sorry that it is written in German language. But the pictures will help to explain.)

So in genetics everything is possible. From no result to infertility to the emergence of a separate species with differentiation by developing an incompatibility to backcrossing with the parents. In the plant kingdom the development of incompatible hybrids

At this point I would also like to refer to another interesting report and quote from it: I think some of you, you maybe anyway, I will already know, A. muricata is also mentioned, sorry not A. coriacea )

Polyploidy in Fruit Tree Crops of the Genus Annona (Annonaceae)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6378316/
https://www.researchgate.net/publication/331019625_Polyploidy_in_Fruit_Tree_Crops_of_the_Genus_Annona_Annonaceae/fulltext/5c6181d692851c48a9ca964d/Polyploidy-in-Fruit-Tree-Crops-of-the-Genus-Annona-Annonaceae.pdf
"Genome duplication or polyploidy is one of the main factors of speciation in plants. It is especially frequent in hybrids and very valuable in many crops. (...) Surprisingly, while the hybrid atemoya has been reported as diploid, flow cytometry analysis of a progeny obtained from an interspecific cross between A. cherimola and A. squamosa showed an unusual ploidy variability that was also confirmed karyotype analysis. hile the progeny from intraspecific crosses of A. cherimola showed polyploid genotypes that ranged from 2.5 to 33%, the hybrid atemoyas from the interspecific cross showed 35% of triploids from a total of 186 genotypes analyzed. With the aim of understanding the possible implications of the production of non-reduced gametes, pollen performance, pollen size and frequency distribution of pollen grains was quantified in the progeny of this cross and the parents. A large polymorphism in pollen grain size was found within the interspecific progeny with higher production of unreduced pollen in triploids (38%) than in diploids (29%). Moreover, using PCR amplification of selected microsatellite loci, while 13.7% of the pollen grains from the diploids showed two alleles, 41.28% of the grains from the triploids amplified two alleles and 5.63% showed up to three alleles. This suggests that the larger pollen grains could correspond to diploid and, in a lower frequency, to triploid pollen. Pollen performance was also affected with lower pollen germination in the hybrid triploids than in both diploid parents. The results confirm a higher percentage of polyploids in the interspecific cross, affecting pollen grain size and pollen performance. The occurrence of unreduced gametes in A. cherimola, A. squamosa and their interspecific progeny that may result in abnormalities of ploidy such as the triploids and tetraploids observed in this study, opens an interesting opportunity to study polyploidy in Annonaceae.
(...)
Polyploidy is believed to be a major mechanism of adaptation and speciation, recognized as a major force in evolution (Van de Peer et al., 2017) and very valuable for crop improvement (Udall and Wendel, 2006; Mason, 2016). Polyploidy is more common in plants than in animals. It is estimated that between 30 and 70% of extant flowering plant species are polyploids (...)"

More I will not paste here. The best is to study the complete report by yourself!

Bytheway...to my new hybridizations of this year there is again a small setback. One of the ovaries, which took weeks to show that pollination was successful, has now decided to dry out after some growth. Another one is still in good shape, I hope it stays that way. Last year, such an ovary grew into a strongly deformed fruit, which is another sign of an unusual way of embryo formation. Unfortunately this fruit dried up in centimeter size and still hangs on the tree like a mummy. I have pictures, but I do not want to overload this post!
„May your choices reflect your hopes, not your fears.“ N. Mandela

Ghost

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Re: Cherimoya/Pawpaw hybrid
« Reply #104 on: September 06, 2020, 03:18:42 AM »
Those plants look extremely healthy. Keep us updated! Great progress

usirius

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Re: Cherimoya/Pawpaw hybrid
« Reply #105 on: September 06, 2020, 03:35:00 PM »
Those plants look extremely healthy. Keep us updated! Great progress
Thanks for your feedback. Yes I will keep you informed as well. There would already be a lot more to tell. For example, the difference in the seedlings - this could perhaps be an indication of differences in the chromosome sets. According to the studies shown in the above-mentioned postscript that seedlings of hybrids can have different chromosome sets in different proportions,. Then I could show pictures of the seeds, which actually looked very strange. Soon I will harvest a pawpaw fruit that was pollinated with cherimoya pollen, I will definitely take pictures of the seeds and document all interesting observations about the future seedlings.
„May your choices reflect your hopes, not your fears.“ N. Mandela

 

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