Kava Botany The real reason why kava is sterile

[Palmetto]

I have a suspicion as to why kava is sterile, based upon past studies. The chromosomes of noble cultivars tend to be around 5 times bigger than the ancestral piper methysticum (citation forgotten sorry). Much of the way that meiosis works in cell division is through the matching of similarly sized chromosomes. If one of the chromosomes is 50% bigger than another, then the gamete can have difficulty creating egg/sperm cells. That is a downside of thousands of years of clonal propagation. Individual chromosomes are no longer forced/ selected for similar sizes to ensure sexual reproducibility.

 

[Zac Imiola (Herbalist)]

@Gourmet Hawaiian Kava

 

[violet]

There's polyploidy too, when the number of chromosomes changes with a cross or mutation. Modern wheat hybrids maintain the accumulated amount of chromosomes from their parentage, for example.

In either situation, this explains why we can't cross different/new/old varieties with each other, but doesn't explain why a variety wouldn't be able to pollinate other plants of same variety as they should be genetically compatible.

It could be a fun project to trace the lineage of the different kava varieties by sequencing their DNA.

 

[Palmetto]

Piper methysticum ssp. wichmannii, which is fertile, has the same number of chromosomes as noble kava (130). They are both decaploid. Piper species have a tendency to be polyploid.

When reprouction occurs primarily through fertilization and seeding, it leads to an evening out of chromosomal sizes, otherwise uneven chromosome sized will cause the genome to be eliminated from the breeding population.

 

[maelstrom]

This reminds me of salvia divinorum. It's been cloned for ages and it's impossible to grow from seed.

 

[Gourmet Hawaiian Kava]

@Gourmet Hawaiian Kava

I am not into genetics so I can not talk about this very much but I do know that the reason that kava can not reproduce is a direct result of man, it was man that kept making cuttings and eventually kava lost the ability to reproduce. I also know that there are some flowers on kava that will sometimes make seeds but they are not viable and they will fall off the flower before maturing.
I can also say that at the last kava conference when Dr. Lebot gave his presentation he did tell us about a new way of looking into the genetics of kava and there were some surprises, at least for me. I will say that the surprises included Mahakea and Isa. This material is unpublished as of now so I can not go into detail.
Aloha.

Chris

 

[kavadude]

How rare are the flowers Chris? Do you have a few or many around your farm?

 

[Gourmet Hawaiian Kava]

How rare are the flowers Chris? Do you have a few or many around your farm?

I see the flowers on all mature kava plants, they just never make seeds, if there were seeds and there have been a report or 2 that there have have been some seen but that was a long time ago, but if there were seeds on the flowers they never mature, the seeds never become viable. I have never seen any seeds at all, ever. Here is some pictures of some kava flowers, look at the long white thing in the leaves.


I hope you enjoy the pictures. Aloha.

Chris

 

[Zac Imiola (Herbalist)]

I did enjoy la pictures

 

[Palmetto]

@Gourmet Hawaiian Kava
Chris,

If Dr. Lebot gave a talk at an open conference, then there is nearly always something published about his talk, especially an abstract. Having written a number of scientific publications, I know that if he shared information at such a talk, then the information immediately becomes part of the public domain. A closed conference can be different. I gave a talk on genomics at an FBI conference once. I don't think anything from that got into the public domain. I must admit, that I think most of the people in that room had better backgrounds in genomics than me.

Now my personal experience is more extensive in palm botany than in kava botany. Over the years, I have thought about how to perform theoretically impossible hybridizations between incompatible species that yet aren't too distantly related. I had many conversations with a famous palm botanist I knew. I explained my approaches, and he gave me tips on how to improve the techniques, since he was a hybridization expert. Then one day, I was reading a comment made by someone who was an expert in a particular palm genus about how many incompatible species will create seeds, but these seeds never ripen all the way. He gave enough detail, that I immediately recognized the missing piece I had been looking for in my techniques.

I wrote up a lengthy protocol for how to hybridize incompatible palm species, but since then I created several similar protocols to do different types of hybridizations (because it is not always as simple as AxB). I have several fruiting trees of 2 species I want to try hybridizing, so I am hoping to do some hybridizing in a few months. I don't think that noble kava would hybridize well with the same protocol, but there is a related protocol that was modified from protocols successfully used for hybridizations in a couple other plant families that probably would work. The resulting hybrids would be infertile, but the resulting kava theoretically ought to be significantly different than just mixing powders from two different cultivars. Plus, it might improve growth and disease resistance for the hybrid compared to the parents. I've thought about testing it out in a few years when my tiny kava plants start flowering someday. I know it's a very brief description, but if you might be interested in some simple experiments, let me know.

 

[verticity]

I see the flowers on all mature kava plants, they just never make seeds, if there were seeds and there have been a report or 2 that there have have been some seen but that was a long time ago, but if there were seeds on the flowers they never mature, the seeds never become viable. I have never seen any seeds at all, ever. Here is some pictures of some kava flowers, look at the long white thing in the leaves.


I hope you enjoy the pictures. Aloha.

Chris

Those are 'male' flowers, right? Aren't the 'female' flowers much more rare?

 

[verticity]

If you could get kava plants to "get it on" (even in a test tube) that would actually be a really good thing. It would increase the genetic diversity of the available cultivars, which is always good for maintaining supply, disease resistance (including diseases that don't exist yet), etc..

For example, bananas, which are also sterile, are actually in danger from disease. The following article describes the problem; however, as one of the commenters notes, it is a bit alarmist, since it fails to note that genetic diversity can arise from mutation, not only from sexual reproduction. But sexual reproduction is a lot more efficient...
http://conservationmagazine.org/2008/09/the-sterile-banana/

Quote: "Pity the banana. Despite its unmistakably phallic appearance, it hasn’t had sex for thousands of years. The world’s most erotic fruit is a sterile, seedless mutant..."​

A lot of people are opposed to genetically engineered foods. I'm not one of those people. If genetic engineering can make a better kava plant, or more disease-resistant banana, I'm all for it..

 

[verticity]

***Although I am against patents on genetically engineered foods. But that is a political and moral objection, not a health objection.

 

[sɥɐʞɐs]

I'm not a scientist or anything...but I'm pretty sure the real reason is:

 

[verticity]

Here is an interesting-looking recent article by Lebot on the genetics of kava:
Comparative analysis of genetic variation in kava (Piper methysticum) assessed by SSR and DArT reveals zygotic foundation and clonal diversification (2015)
Interesting quote from the abstract:

"...In the Vanuatu archipelago, noble cultivars originating from different islands clustered together within a very narrow genetic base despite their diversity of morphotypes. SSR and DArT fingerprints allowed the identification of kava cultivars unsuitable for consumption, so called two-days, and clearly differentiated the wild types classified as P. methysticum var. wichmannii from the cultivars as var. methysticum. Molecular data reveals that all noble cultivars evolved by the predominance of clonal selection. Although they are represented by clearly distinct morphotypes, these cultivars are genetically vulnerable and their potential to adapt to forthcoming changes is limited...."
​

@Henry do you have the full text of this available to you?

 

[verticity]

I'm not a scientist or anything...but I'm pretty sure the real reason is:
View attachment 6882

I know. Don't they understand that plants actually crave Dr. Pepper?

 

[sɥɐʞɐs]

I know. Don't they understand that plants actually crave Dr. Pepper?

...and that Diet Dr. Pepper tastes more like regular Dr. Pepper!

 

[verticity]

...and that Diet Dr. Pepper tastes more like regular Dr. Pepper!

Little known fact: The Irish potato famine was caused by Mr. Pibb.

 

[Palmetto]

@verticity, I looked up that abstract today, but didn't look hard enough to find the whole paper. I'm trying harder to find a Marquesan source for the elusive superkava Avini ute. Who needs the legendary Mohikana, if you have it's twin brother.

 

[sɥɐʞɐs]

@verticity, I looked up that abstract today, but didn't look hard enough to find the whole paper. I'm trying harder to find a Marquesan source for the elusive superkava Avini ute. Who needs the legendary Mohikana, if you have it's twin brother.

I think I remember Avini Ute being a Tahitian cultivar(of course, there is bleed over in the languages) ...I tried to contact some random strangers in Tahiti once, in hopes of finding it, but they seemed to think Kava wasn't around there...probably 'cause they were French and not indigenous.