Quest for mold-resistant strains, Hawaii outdoor greenhouse grow

[cbdhemp808]

I was going to build a couple SIPs this weekend, but we had some off-grid electricity problems to work through, now fixed.

Shooting for Monday now.

 

[cbdhemp808]

I brought this over from another thread, since it's pertinent to my quest for fungus/mold resistant strains...

Sativa grow in tropical climates. They veg in the rainy season (summer) and flower in the early dry season (winter). So they have a natural morphology and genetic resistance to mold. They have more space between leaves for air flow and long thin buds that dry quicker. They generally grow in locations with a constant 10mph+ "tropical breeze".

Choosing a location with a steady breeze and pruning for air through the plant are the most important factors. How many weeks do you have from 13/11 days to the rainy season? 6 weeks, use a fast flowering indica. 8 weeks, use a tolerant sativa. Rain right before harvest isn't enough time for mold to be an issue.

It all depends on what you mean by "sativa". There are the original sativas before humans started breeding cannabis, probably tall plants likely related to modern-day industrial hemp, with very low amounts of cannabinoids. Then there are the landrace sativas that were bred by humans which incorporated indica genetics for potency. And then there are the modern sativa/indica hybrids which are known as sativa-dominant.

[EDITED] Here's Mango Thai, a landrace sativa from Laos with big, long colas. This one is likely resistant to fungus/mold, but I don't think it's because of the morphology or something hidden in the genetics, or local tropical adaptation, etc. I think the natural resistance is directly from two things: 1) high resin production and 2) high amounts of pine terpenes, which give a piney/skunky odor. I believe the original incorporation of these terpenes into sativa genetics comes from Afghan Kush genetics (and probably other landraces from cool, dry climates, such as Nepal).

photo: The Real Seed Company

Here's another landrace sativa, Honduras, showing plenty of pine terpenes...
"...mainly contains the following monoterpenes: very high amounts of terpinolene and high amounts of beta myrcene, with variability in the high alpha pinene content, followed by moderate quantities of trans ocimene and variability in the moderate content of beta pinene, and smaller amounts of cedrol, limonene, linalool, trans phytol, alpha phellandrene, alpha terpineol, alpha terpinene, gamma terpinene..."

photo: Ace Seeds

I think there are plenty of modern sativa/indica hybrids, known as sativa-dominant, which are not naturally resistant to fungus/mold, which may have what most would consider an ideal morphology.

So, one can attempt to work with particular sativa-dominant phenos and make the environment as best as possible to minimize the impact of fungus/mold, or one can determine the terpene profile of the particular pheno to be grown.

I am interested in growing sativa, indica, and 50/50, but in terms of sativa I'm looking for a fast-flowering sativa-dominant pheno with high pine terpenes. There are a bunch of options. And then there's the issue of pheno hunting to find the ones with the high pine terpenes, and so I'm trying to select the best options with minimal hunting involved, so that means a well-bred, stable seed line with one or more sativa phenos, and few or one indica pheno.

By sativa I am referring to genus sativa sativa that can only grow in tropical conditions originating from south east Asia. Not the sub genus sativa indica that only grows in cool arid conditions originating in middle east. Yes, they both share lineage belonging to the family, hemp cannabis from Himalayas. They are genetically different genus of the same family. Sativa was the genus origin of the THC trait, passed down to it's subclass sativa indica. Yes, plants naturally growing in areas between northern temperate and equatorial zones will be a hybrid and still be a distinct land strain. All true equatorial land strain will be sativa and arid temperate land strain will all be indica. True pure genetics are hard to find in a commercial seed bank.

The Real Seed Company describes Mango Thai #2, a traditional Lao sativa landrace, as Cannabis sativa subsp. indica var. indica. They describe indicas as Cannabis sativa subsp. indica var. afghanica. This is from the "new cannabis taxonomy" of McPartland and Small, 2020.

So, what we call a true sativa domesticate is Cannabis sativa subsp. indica var. indica, and what we call a true indica domesticate is Cannabis sativa subsp. indica var. afghanica.

C. sativa subsp. sativa var. sativa is from an older taxonomy, Small and Cronquist, 1976.

The wild ancestral relatives are: for "sativa", C. sativa subsp. indica var. himalayensis (in South Asia), and for "indica", C. sativa subsp. indica var. asperrima (in Central Asia).

Cannabis sativa subsp. indica var. indica (informally, "sativa" domesticate) was "Originally cultivated in India for gañjā, and spread at an early date to southeast Asia, Africa, and the Americas." This domesticated version was derived from the regional wild type, C. sativa subsp. indica var. himalayensis. Both are typically tall plants, contain THC, and are late maturing. These types tend to be less susceptible to botrytis bud rot, and contain significantly more terpinolene than var. afghanica.

"The morphology of var. himalayensis [wild sativa] shares traits with East Asian hemp, such as tall height, relatively hollow shoots with a high percentage of bast fiber and little wood; leaflets with moderately coarse serrations; [colas] elongated and somewhat loose..."

Cannabis sativa subsp. indica var. afghanica (informally, "indica" domesticate) was grown in Central Asian regions: Afghanistan, and others including "Pakistan, Turkestan (Uzbekistan, Tajikistan, Kyrgyzstan, Xīnjiāng Region in China), and Iran." This domesticated version was derived from the regional wild type, C. sativa subsp. indica var. asperrima. Both types are typically small plants, contain more THC than "sativas", and more CBD. They are early maturing. These types tend to be more susceptible to botrytis bud rot.

Genetics only play a small part in mold resistance if you control where and how it grows. Grew outdoors for decades and only ever had one plant get mold.

Genetics impart some percentage of either C. s. var. indica ("sativa") or C. s. var. afghanica ("indica"), to produce what we call "sativa-dominant", "indica-dominant", or 50/50 balanced. A plant that exhibits strong sativa traits will typically have the best chance of natural resistance to botrytis. Some indica-dominant or indica-leaning hybrids will contain enough sativa-associated pine terpenes (incl. terpinolene) to also have natural resistance to botrytis.

[ There is some confusion, however, because McPartland and Small are reporting that C. S. var indica ("sativa") is associated with terpinolene. In my research, I have found that Afghan Kush is high in terpinolene, which can be seen in current lab test results. My understanding is that early sativa domesticates gained both potency and specific pine terpenes including terpinolene by crossing with indica domesticates. Perhaps actually the opposite is true—early Central Asian indica domesticates gained terpinolene and other pine terpenes from India's early sativa domesticates, and this is how modern Afghan Kush landraces wound up with the pine terpenes. It is common to see some modern sativas that are terpinolene-dominant, but it appears rare to impossible to find a terpinolene-dominant modern indica, with a couple exceptions being some phenos of Afghan Kush and Northern Lights #5. ]

Where I'm growing outdoors here in Hawaii is a perfect test-bed for botrytis resistance, because we can grow year round and the conditions for botrytis to develop are ideal year round. I've had sativas get bud rot, and indicas get bud rot, and then a pheno of a specific 50/50 not get any bud rot whatsoever. These are all growing under the same environmental conditions, in the same place in my greenhouses. This means that genetics play a central role, and expression of terpenes is directly an outcome of genetics.

So again, the only way to have some degree of certainty of strong natural resistance to bud rot is to know the terpene profiles of the known phenotypes of a seed line.

 

[cbdhemp808]

Here's another one I brought from another thread, since it's pertinent to my quest for fungus/mold resistant strains...

Ah see that's also what I thought, what Sativa70 is saying, Sativa morphology very different and maybe very airy for a reason.

A lot of people will say that the sativa morphology contributes to bud rot resistance. I haven't experienced that in my grow, and as I'm saying, my conditions are ideal to test this. Landrace tropical sativas are big plants with big, long colas. I think this morphology isn't some kind of a magic bullet against botrytis spores landing on bud surfaces, taking hold, and growing. A bud is a bud, and a cola is a cola—the botrytis organism doesn't care. But if these spores land in a trichome forest that's off-gassing anti-fungal terpenes, this lowers their ability to take hold. That's my understanding. The pine terpenes are anti-fungal.

Today I took at look at this paper written by McPartland and Small in 2020. They are confirming that terpinolene is associated with the original domesticated sativas in India.

From a study done in Egypt in 2018:

"In the case of [Botrytis cinerea], (–)-menthone, eugenol, and α-terpinene were among the most potent mycelial growth inhibitors." (α-pinene was also strong)

Terpinolene is δ-terpinene (delta), but sometimes α-terpinene is also called terpinolene—they are closely related molecules (almost identical).

My post from 2023 explains more and shows the size of a trichome compared to botrytis spores.

Isn't there something else in the genetic make up that defines resistance, can't be that only pine-y weed is?

This is a very good question. I've studied this quite a bit. My understanding is there is a defense signalling system inside the cannabis plant, and this signalling results, at least in part, in the release of cannabinoids and terpenes from the trichomes. (There may be other mechanisms inside the plant that bring chemical defense to the site of infection; however, I am not aware of those—the literature is quite complex.) Some phenotypes may have better signalling than others. So for example, it's possible that the sativas have better signalling for specific pathogens, but nonetheless, the cannabinoids and terpenes must be there and present in order to be activated.

So, it makes total sense to me that the trichomes have a primary role in defense against botrytis bud rot, with their sticky resin and off-gassing anti-fungal terpenes. The terpenes are there for functional reasons, and cannabis produces hundreds of different terpenes.

what do you do if you don't really like that flavour?

Another good question! Well, I for one don't really care. To me it's far more important not to have to deal with bud rot which can destroy a whole harvest. That said, the presence of terpinolene and other pine terpenes may be sufficient to bring strong bud rot resistance, while at the same time myrcene, limonene, and beta-caryophyllene may also be prominent, rounding out the overall flavor. Lots of true sativas will have terpinolene and pine terpenes. Terpinolene flavor is described as sweet, citrus, floral, pine. Weedmaps describes Northern Lights #5 flavor as "sweetly tropical with a subtle herbal musk". NL5 is an indica with substantial terpinolene and pine terpenes.

So do high Terpinoline & Pinene strains come from very humid areas? as per natural selection?

As I mentioned above, yes, they originated in warm, tropical, wet India. At some point in the evolution of cannabis, some phenotypes began producing terpinolene and the other pine terpenes in the trichomes. If these helped the plant's defense against tropical pathogens, then the phenotype would survive and reproduce more than those which did not produce these terpenes.

And I'm just now reading mandala seeds seem to have a nice section on bud rot;

https://www.mandalaseeds.com/Guides/Preventing-Bud-Mold

They talk about everything BUT terpenes, and didn't explain that phenotypes of strains will have different distinct terpene profiles. They are conveying the traditional approach of recommending the planting of strains that are adapted to a specific climate, etc. What I've been driving at is, what exactly is going on that provides the natural resistance, and how can we predict that? I think the answer clearly lies with phenotypes and terpene profiles, and ultimately with terpinolene and the other pine terpenes. Simply planting strains that are adapted to a specific environment bypasses the fact that for any given stable seed line, there will be at least two phenotypes. One pheno could be sativa dominant, while the other indica dominant. Some strains produce 5 or 7 known phenotypes, each with its own terpene profile.

 

[Melville Hobbes]

It is common to see some modern sativas that are terpinolene-dominant, but it appears rare to impossible to find a terpinolene-dominant modern indica, with a couple exceptions being some phenos of Afghan Kush and Northern Lights #5. ]

Selective breeding is an issue here. I've seen threads about indica landraces where the grower is quite aggravated by how "energetic" his indica turned out to be, and they often end with "I won't be growing that one again".
Modern indicas are bred for sedative traits, and have been for decades. Landraces are what you need to look at, if you're looking for the origins of terpinolene dominant plants.

As I mentioned above, yes, they originated in warm, tropical, wet India.

According to that one quote from McPartland, and your supposition that terpinolene spread from sativa strains into indicas, but you mentioned there that your research indicates the opposite.

A trait doesn't need an evolutionary pressure to arise, just to become dominant. A random mutation that has neither benefits nor drawbacks in the region it originates in may have benefits in other areas, where it then becomes the dominant trait.
Dinosaurs grew feathers before they started to fly.