Flowering Dark Period: What is the Minimum to Begin Flowering Your Strain?

[djonkoman]

don't know of any threads discussing specifically that auto x photo thing, but I can name a few commercially available strains that use it.
there is one seedbank that offers a line of 'f1 fast version' strains. if you look into the descriptions, pretty clear they're using this phenomenon.
another strain is thaipassion.

my personal theory how it could work is this:
the auto mutation is probably a mutation causing some kind of compound in the flowering signal pathway to be constantly produced, while normally production of that compound would need a trigger. so basically, it's a switch that's stuck in the 'on'-position.
in case a plant is heterozygous for that gene(1 autoflower allele, 1 photo allele), it will also produce that compound from it's auto-gene, but half the amount that would be produced if it had 2 auto-alleles.

we know a f1 auto x photo is photo, autoflower is recessive. so clearly, the amount of this compind produced from 1 autoflower allele is not sufficient to trigger flowering. stuff like this is common with biological pathways where you have a 0-1 outcome(as in, either it's triggered to flower, or it's not, there's no gradient, just on or off). in such cases, there's usually a tresshold-value. below the tresshold=off, above it =on. similar thing is the case with the electric impulses in neurons for example.

so, assuming this autoflower allele produced a certain level of this flower-trigger compound, but jut below the tresshold. that means it won't flower from just that autoflower allele alone, but since it does have a base-level only a little below the tresshold level, it would just need a little bit extra to go above the tresshold. so even just a little triggering of the photo-allele could push it above the tresshold.

similar thing you have for example with neurons, where a certain trigger can be below the tresshold, but it basically makes the neuron more sensitive since it's closer to the tresshold, and any extra impulse pushes it over the edge.

 

[Douglas.Curtis]

Ok, now this is fascinating. The combination of 'veg all you want' and a specific trigger for flowering which is not necessarily photon based. Ty for sharing this djonkoman, I hope you're correct as it would mean even more variability than we currently have. Wow.

 

[Treevly]

With the rise of popularity of autoflowers I think they now got renamed to semi-autoflower. But they are not true autoflowers because they contain no Ruderalis.

Does a plant need to contain Ruderelis DNA in order to be called autoflowering? I've seen Lebanese hash plants flower in late spring because they were sprouted too early and were so-many days old when put outside. After so many days, they just flower. It was a considerable surprise to me.

 

[djonkoman]

Ok, now this is fascinating. The combination of 'veg all you want' and a specific trigger for flowering which is not necessarily photon based. Ty for sharing this djonkoman, I hope you're correct as it would mean even more variability than we currently have. Wow.

eh, it's interesting in a curiosity way, but imo not much practical use, it's more a negative trait to be bred out imo. the rootbound-flowering has just given me issues with revegging plants after plantout/repotting, it's not really that feasible imo to keep a plant rootbound from the start of flowering till the end, unless you just want to make a few seeds.
one of my more failed plants this year for example is such a plant, was nice and early into flower, but it was time for transplant, after repotting it started revegging but didn't go fully back into veg, and now I've harvested a leafy, heavily branched mess with thin buds. and at the start of that reveg it also hermed(luckily not too much, so I could pluck out most of the balls before pollination could happen). at least it smells nice.
it's also not unique to weed, plenty of other plants can also be triggered to flower by stresses such as being rootbound, in a last effort to reproduce before they'll die. so it's not that strange weed does it too, just these certain strains are extra sensitive to it.
it's the same pathway for flowering as what lighthours trigger, just that stresses such as rootbinding bypass the light-trigger and can trigger the flower pathway even in the absence of the right daylength.

 

[Douglas.Curtis]

Does a plant need to contain Ruderelis DNA in order to be called autoflowering? I've seen Lebanese hash plants flower in late spring because they were sprouted too early and were so-many days old when put outside. After so many days, they just flower. It was a considerable surprise to me.

I'd be interested in seeing what the flower times are under 24/0 lighting.

djonkoman, root bound is my least favorite and I know what you mean. I keyed in on using a 'trigger' to turn on the flowering switch, not the root bound part.