Inducing Flowering in Hops

[Xier]

I will start by citing two studies:

----------------------------------------------------------------------

H. L. SHEPHARD, J. S. PARKER, P. DARBY and C. C. AINSWORTH. Sexual
development and sex chromosomes in hop. New Phytol. (2000), 148, 397-411

"The switch from vegetative to reproductive development in female hop plants is triggered by shortening daylength (Tournois, 1912; Thomas & Schwabe, 1969). The critical daylength is genotype-dependent, although plants of both sexes must initiate a minimum number of nodes before flowering can be induced (e.g. 30-32 for the variety `Fuggle' ; Thomas & Schwabe, 1969). The influence of daylength on floral induction in male hop plants is less clear. Once these conditions and certain other environmental factors such as temperature are met, the plant switches from the vegetative to the reproductive phase."

And:

Factors Controlling Flowering in the Hop (Humulus lupulus L.)
G. G. THOMAS and W. W. SCHWABE

"In experiments on the effects of daylength on the growth and flowering of the perennial hop it was shown that Humulus lupulus is a short-day plant. The absolute length of the short day is important since very short days (8h) induce dormancy before flowering can occur. Light-break treatment may therefore promote or inhibit flowering according to the associated main photoperiod. A minimum node number must have been differentiated before the hop can be induced to initiate flowers, an effect analogous to the juvenile condition. Minimum leaf number and critical daylength for induction depend on variety. At low temperature, induction is possible with longer photoperiods. Promotion of flowers by growth retardants (B9 and CCC) in unfavourable daylengths, and delay of initiation by gibberellic acid treatment were also observed."

And:

Effects of Plant Growth Regulators on Growth and Reproduction of Humulus lupulus
Newton Chad Rowland, Tennessee State University

"Traditionally, in the US, hops are grown in the field in northern latitudes without the use of plant growth regulators (PGR). This research was to find out if the use of PGR could sufficiently reduce the height of hop vines to allow them to be grown in a greenhouse and produce similar flower yield of those grown in the field at northern latitudes. The hop cultivar Cascade was chosen for this study after it was compared in a preliminary trial with 'Perle', 'Fuggle' and 'Magnum'. In that initial trial, 'Cascade' produced the highest yield and appeared to be better adapted for growth under greenhouse environments using hydroponics. Of the four PGR's (Sumagic, Cycocel, B-9, and A-Rest) evaluated, only Sumagic had any effect on reducing vine length. Treatments that yielded the highest reduction in vine length (325 cm) was Treatment #1 (5 ppm) of Sumagic. Application of Sumagic slightly affected the average wet flower weight from 259, 226.5, 324, 284, and 282.5 grams from 5ppm to 0ppm, respectively. The first internode measurements had average lengths of 3.25, 7.75, 12.25, 14.5, and 18.25 centimeters 5.0 ppm to 0.0 ppm, respectively. Each Treatment yielded results that were significantly different from each other. All vine length reductions were significantly different. Treatments #1 (5 ppm), #2 (2.50 ppm), and #4 (0 .62 ppm) yielded had average lengths of 421.06, 417.44, and 430.00 centimeters respectively. Wet flower yield were 104.88, 251.50, 217.75, 257.38, and 213.75 grams from 5ppm to 0ppm, respectively. The first internode measurements produced average lengths of 3.62, 6.88, 10.50, 15.19, and 18.44 centimeters from 5.0 ppm to lowest 0.0 ppm of PGR. Results of the second experiment yielded similar results for vine reduction and flower yield."
----------------------------------------------------------------------

Now, the reason I am bringing these studies and this concept to your attention is for those wishing to breed hops from seeds. It seems I will soon have to do the same and I realized what a waste of time and resources it will be to grow 100 seeds and keep just a few plants. The solution to the dilemma seemed obvious:

I would have to eliminate the undesirables as quickly as possible before they consumed too much space and time... But, to know what plants were desirable, I would need flowers. And, to have flowers before the plants consumed space meant I would need to manipulate their natural growth.

Here is my treatise:

1. Start with as large a selection of seeds as possible and plant them in containers that can easily be brought indoors.
2. Spray a gibberellin inhibitor like Sumagic® regularly after the plants have passed the seedling stage to keep them dwarfed.
3. Upon reaching a safe 40 nodes, switch to a 12/12 light cycle by leaving the plants outdoors, during the day and in the sun, for twelve hours and then bringing them inside to a cool dark place like a cellar or basement for twelve hours.
4. When plants begin to flower, analyze all of your plants and cull the undesirables.
5. Switch to an 8/16 hour cycle to induce dormancy in remaining plants.
6. After a small dormant period, bring plants back outside and let them finish the season.
7. Have a beer.

The main reason for this treatise is for space concerns when trying to breed new varieties on a small scale. Growing hundreds of unreliable plants would normally be outside of the reach of a small hobbyist, but maybe with this methodology, it is slightly more doable.

Also, I assume the plants would reach 40 internodes much quicker when the space between each node is about 1/5th of what it would otherwise be.

I welcome all feedback.

 

[PapaBearJay]

I will start by citing two studies:

----------------------------------------------------------------------

H. L. SHEPHARD, J. S. PARKER, P. DARBY and C. C. AINSWORTH. Sexual
development and sex chromosomes in hop. New Phytol. (2000), 148, 397-411

"The switch from vegetative to reproductive development in female hop plants is triggered by shortening daylength (Tournois, 1912; Thomas & Schwabe, 1969). The critical daylength is genotype-dependent, although plants of both sexes must initiate a minimum number of nodes before flowering can be induced (e.g. 30-32 for the variety `Fuggle' ; Thomas & Schwabe, 1969). The influence of daylength on floral induction in male hop plants is less clear. Once these conditions and certain other environmental factors such as temperature are met, the plant switches from the vegetative to the reproductive phase."

And:

Factors Controlling Flowering in the Hop (Humulus lupulus L.)
G. G. THOMAS and W. W. SCHWABE

"In experiments on the effects of daylength on the growth and flowering of the perennial hop it was shown that Humulus lupulus is a short-day plant. The absolute length of the short day is important since very short days (8h) induce dormancy before flowering can occur. Light-break treatment may therefore promote or inhibit flowering according to the associated main photoperiod. A minimum node number must have been differentiated before the hop can be induced to initiate flowers, an effect analogous to the juvenile condition. Minimum leaf number and critical daylength for induction depend on variety. At low temperature, induction is possible with longer photoperiods. Promotion of flowers by growth retardants (B9 and CCC) in unfavourable daylengths, and delay of initiation by gibberellic acid treatment were also observed."

And:

Effects of Plant Growth Regulators on Growth and Reproduction of Humulus lupulus
Newton Chad Rowland, Tennessee State University

"Traditionally, in the US, hops are grown in the field in northern latitudes without the use of plant growth regulators (PGR). This research was to find out if the use of PGR could sufficiently reduce the height of hop vines to allow them to be grown in a greenhouse and produce similar flower yield of those grown in the field at northern latitudes. The hop cultivar Cascade was chosen for this study after it was compared in a preliminary trial with 'Perle', 'Fuggle' and 'Magnum'. In that initial trial, 'Cascade' produced the highest yield and appeared to be better adapted for growth under greenhouse environments using hydroponics. Of the four PGR's (Sumagic, Cycocel, B-9, and A-Rest) evaluated, only Sumagic had any effect on reducing vine length. Treatments that yielded the highest reduction in vine length (325 cm) was Treatment #1 (5 ppm) of Sumagic. Application of Sumagic slightly affected the average wet flower weight from 259, 226.5, 324, 284, and 282.5 grams from 5ppm to 0ppm, respectively. The first internode measurements had average lengths of 3.25, 7.75, 12.25, 14.5, and 18.25 centimeters 5.0 ppm to 0.0 ppm, respectively. Each Treatment yielded results that were significantly different from each other. All vine length reductions were significantly different. Treatments #1 (5 ppm), #2 (2.50 ppm), and #4 (0 .62 ppm) yielded had average lengths of 421.06, 417.44, and 430.00 centimeters respectively. Wet flower yield were 104.88, 251.50, 217.75, 257.38, and 213.75 grams from 5ppm to 0ppm, respectively. The first internode measurements produced average lengths of 3.62, 6.88, 10.50, 15.19, and 18.44 centimeters from 5.0 ppm to lowest 0.0 ppm of PGR. Results of the second experiment yielded similar results for vine reduction and flower yield."
----------------------------------------------------------------------

Now, the reason I am bringing these studies and this concept to your attention is for those wishing to breed hops from seeds. It seems I will soon have to do the same and I realized what a waste of time and resources it will be to grow 100 seeds and keep just a few plants. The solution to the dilemma seemed obvious:

I would have to eliminate the undesirables as quickly as possible before they consumed too much space and time... But, to know what plants were desirable, I would need flowers. And, to have flowers before the plants consumed space meant I would need to manipulate their natural growth.

Here is my treatise:

1. Start with as large a selection of seeds as possible and plant them in containers that can easily be brought indoors.
2. Spray a gibberellin inhibitor like Sumagic® regularly after the plants have passed the seedling stage to keep them dwarfed.
3. Upon reaching a safe 40 nodes, switch to a 12/12 light cycle by leaving the plants outdoors, during the day and in the sun, for twelve hours and then bringing them inside to a cool dark place like a cellar or basement for twelve hours.
4. When plants begin to flower, analyze all of your plants and cull the undesirables.
5. Switch to an 8/16 hour cycle to induce dormancy in remaining plants.
6. After a small dormant period, bring plants back outside and let them finish the season.
7. Have a beer.

The main reason for this treatise is for space concerns when trying to breed new varieties on a small scale. Growing hundreds of unreliable plants would normally be outside of the reach of a small hobbyist, but maybe with this methodology, it is slightly more doable.

Also, I assume the plants would reach 40 internodes much quicker when the space between each node is about 1/5th of what it would otherwise be.

I welcome all feedback.

Let's start with this. The PGR study.

I know which study you're referring too, in fact, I'm looking at the published 2011 results Chad provided at the Southern Nursery Association Conference right now. His data shows that heights were only reduced to between 160-185 inches, that is plant sizes were reduced from roughly 15.5 ft to 13 ft. That's not manageable by most people to carry around.

That said, I'm not sure where you're getting your results unless he has since published other work.

Second, the amount of labor that it would take to haul several hundred plants around at any one time, just to induce flowering is somewhat of a pain. Since we're there already, let's not fail to mention that hops don't flower until the second year (from seed). Yes, that's correct, they need a period of vernalization in order to flower. It is a well-documented process that is found in most temperate plant species. Also, let's not forget that acute toxicity that arises from continuous application of PGRs, because of the interference with the normal processes that occur within the plant, you end of with a hyper-accumulation of minerals and nutrients within the plant tissue. This is also well-recorded, especially in greenhouse environments, as those are the only places that are LEGALLY allowed to use such chemicals minus land care individuals, who still must operate under the law. This then brings us to the next piece, that currently there are restrictions for the use of PGRs on hops. You cannot LEGALLY use them on hops.

Also, yes, they need a period of dormancy. But that period of dormancy must also be a cold period below a certain temperature otherwise the hop will not be vernalized, thus leading it to not flower the following season, or at least a significant reduction in yield will be seen.

Just saying....

 

[B-Hoppy]

Since we're there already, let's not fail to mention that hops don't flower until the second year (from seed). Yes, that's correct, they need a period of vernalization in order to flower. It is a well-documented process that is found in most temperate plant species.

Must be the whole 'climate change' thing going on because I had 8 or 9 seedlings come up last year and all but two showed their sex by August. I never really gave it a second thought, but in the past I always had to wait until year two to find out. Thought I as on to something, ha!

 

[PapaBearJay]

Interesting, chance you have pictures of it?

 

[B-Hoppy]

I tried taking a pic of some of the cones infected with downy mildew but couldn't figure out how to focus on the cones. The pictures came out focusing on the background so I bagged them. Like I said, it was unusual to see them show in the first year. The male was bagged as were the two gals that were disease magnets.

 

[PapaBearJay]

I tried taking a pic of some of the cones infected with downy mildew but couldn't figure out how to focus on the cones. The pictures came out focusing on the background so I bagged them. Like I said, it was unusual to see them show in the first year. The male was bagged as were the two gals that were disease magnets.

Had lots of issues with downy mildew?

 

[B-Hoppy]

Over the years, yes. Mostly it's just a few spikes here and there but last year I got behind on monitoring and the weather conditions made it a bigger problem than it usually is. All the seedlings were in very close proximity and the two gals had a very bad response so there's no sense in keeping them. So, "off with their heads"!

 

[Xier]

Let's start with this. The PGR study.

I know which study you're referring too, in fact, I'm looking at the published 2011 results Chad provided at the Southern Nursery Association Conference right now. His data shows that heights were only reduced to between 160-185 inches, that is plant sizes were reduced from roughly 15.5 ft to 13 ft. That's not manageable by most people to carry around.

That said, I'm not sure where you're getting your results unless he has since published other work.

Second, the amount of labor that it would take to haul several hundred plants around at any one time, just to induce flowering is somewhat of a pain. Since we're there already, let's not fail to mention that hops don't flower until the second year (from seed). Yes, that's correct, they need a period of vernalization in order to flower. It is a well-documented process that is found in most temperate plant species. Also, let's not forget that acute toxicity that arises from continuous application of PGRs, because of the interference with the normal processes that occur within the plant, you end of with a hyper-accumulation of minerals and nutrients within the plant tissue. This is also well-recorded, especially in greenhouse environments, as those are the only places that are LEGALLY allowed to use such chemicals minus land care individuals, who still must operate under the law. This then brings us to the next piece, that currently there are restrictions for the use of PGRs on hops. You cannot LEGALLY use them on hops.

Also, yes, they need a period of dormancy. But that period of dormancy must also be a cold period below a certain temperature otherwise the hop will not be vernalized, thus leading it to not flower the following season, or at least a significant reduction in yield will be seen.

Just saying....

Ah, but you are missing the main point; they will be induced to flower before they reach their full height. If you read the other two studies, they cite number of internodes as a requirement before using a shift in light-cycle to induce flowering. Using 5 PPM of of Sumagic, the average internode length was 3.25cm; that would be 130cm at 40 nodes, or just a little over 4 feet. Also, 5 PPM was the highest concentration and results are following a pretty obvious curve. Using 10 PPM may result in 40 nodes at near 2 feet!

Once the required node count has been reached, they would be induced to flower by changing their light cycle. I don't have access to the full study, but I imagine 12/12 would work fine. I might set up a grow room just for this purpose and do a SOG grow; in that case, I wouldn't even need to move them and could do it all completely indoors.

As for the legality, I doubt those laws apply to research-purposed hops produced at home and for your own use; they are most certainly meant for hop farmers. Further, I'm in China and I'm quite sure no one gives a hoot what we do with our plants here... I love this place.

 

[PapaBearJay]

But, you are missing the point; they will be induced to flower before they reach their full height. If you read the other two studies, they cite number of internodes as a requirement before using a shift in light-cycle to induce flowering. Using 5 PPM of of Sumagic, the average internode length was 3.25cm; that would be 130cm at 40 nodes, or just a little over 4 feet. Also, 5 PPM was the highest concentration and results are following a pretty obvious curve. Using 10 PPM may result in 40 nodes at near 2 feet!

Once the required node count has been reached, they would be induced to flower by changing their light cycle. I don't have access to the full study, but I imagine 12/12 would work fine. I might set up a grow room just for this purpose and do a SOG grow; in that case, I wouldn't even need to move them and could do it all completely indoors.

As for the legality, I doubt those laws apply to research-purposed hops produced at home and for your own use; they are most certainly meant for hop farmers. Further, I'm in China and I'm quite sure no one gives a hoot what we do with our plants here... I love this place.

No, actually those laws apply to everyone in the US. State laws may differ, but if the product is not labeled for use with a specific crop, it cannot be used on that crop. Detailed records for both growers and producers must be kept at all times, as there are many guidelines that the system must follow.

They're actually not "meant" for hop farmers, they're a byproduct of the greenhouse/agribusiness industry. Has research been done on hops with them, yes, of course. They also stopped in the early 70's when they realized their toxic effects.

That's correct, they need a certain number of nodes, this applies to many plants in fact, not just hops.

Also, I don't think you're following what I'm saying. Uniconazole is only effective for a short period of time, that is it needs to be continuously applied to the plant over the entire season. The end results of Chad's experiments lead to plants still resulting in 13 ft tall. The first node measurement was only that, not a measurement of the entire plant. That said, there is also an inverse trend in relation to yield. You might have a greater number of nodes per distance, but the yield from the 5ppm spray was less than half the 2.5ppm. If you apply 10ppm you'll such a reduction in yield you won't be getting any seed anyways. Not too mention the possibilities associated with infertility due to PGR application. Even if you get a plant to flower at 2 ft tall, it's likely you won't collect viable pollen or seed due to the amount of stress you've placed on those plants.

I'm also very aware of the other two studies, I've cited them many times before. But you haven't clued me in on anything I didn't already know.

 

[Xier]

No, actually those laws apply to everyone in the US. State laws may differ, but if the product is not labeled for use with a specific crop, it cannot be used on that crop. Detailed records for both growers and producers must be kept at all times, as there are many guidelines that the system must follow.

They're actually not "meant" for hop farmers, they're a byproduct of the greenhouse/agribusiness industry. Has research been done on hops with them, yes, of course. They also stopped in the early 70's when they realized their toxic effects.

That's correct, they need a certain number of nodes, this applies to many plants in fact, not just hops.

Also, I don't think you're following what I'm saying. Uniconazole is only effective for a short period of time, that is it needs to be continuously applied to the plant over the entire season. The end results of Chad's experiments lead to plants still resulting in 13 ft tall. The first node measurement was only that, not a measurement of the entire plant. That said, there is also an inverse trend in relation to yield. You might have a greater number of nodes per distance, but the yield from the 5ppm spray was less than half the 2.5ppm. If you apply 10ppm you'll such a reduction in yield you won't be getting any seed anyways. Not too mention the possibilities associated with infertility due to PGR application. Even if you get a plant to flower at 2 ft tall, it's likely you won't collect viable pollen or seed due to the amount of stress you've placed on those plants.

I'm also very aware of the other two studies, I've cited them many times before. But you haven't clued me in on anything I didn't already know.

You continue to not understand what I am saying; the plants in the study were subjected to a normal growing season. If we extrapolate that all internode lengths could be maintained at ~ 3 cm, the plant's in the experiments must have had many more nodes than the control.

The plants would have also reached 40 internodes before the control. Once the plants reach 40 internodes, I would then change their light-cycle to induce flowering. That is , instead of an entire season, they would only experience a partial-season.

Do you see where I am going with this? The height reduction in the study cited was minor, and irrelevant. I am not aiming to use PGR to reduce the height; I am using it to reduce internode length. Once I have the adequate number of nodes, I will use a different light-cycle to induce flowering. Once flowering begins, I can cut back any unwanted growth.

Further, this is for the purpose of finding desirable plants, not producing seeds. Once the plants have been identified that have desired aroma and such, the others will be culled and the desired plants will be prepared for the next year of normal growth.

I apologize for not being clear enough from the beginning.

 

[brewerelated]

There are also dwarf varieties of hop plants. They are harder to find, but I have read that some dwarf varieties can naturally produce decent yields on 8-10 foot trellis.

If you can get a hold of some of these dwarf plants perhaps you can experiment using the methods above to get them to flower on even shorter plants.

Check this page out:

http://adha.us/dwarf-hops

 

[nagmay]

I seem to be a little late to the party, but here is my 2 cents:

First year seedlings can most certainly produce flowers. 2 out of the 3 plant that I started last year had full size flowers by August of their first year without any treatment.

The idea of inducing flowers on young plants to pick desirable traits is intriguing. However, it may be more difficult than you anticipate. The flavors and acid levels can vary widely between cones on the same, mature plant. Environmental factors such as the amount of sun to the cones can play a big part. I have also personally noticed that the cones from young plants can be very different than cones from a mature plant of the same variety.

It is an interesting idea and I wish you the best. Keep us informed of our progress.

 

[Xier]

There are also dwarf varieties of hop plants. They are harder to find, but I have read that some dwarf varieties can naturally produce decent yields on 8-10 foot trellis...

Interesting, I hadn't heard of the dwarf varieties before. What I will probably end up doing is setting up a grow room first and posting pictures online. When everyone sees the setup and gets interested, I will ask them to donate seeds for the experiment. It won't be till later this year though.

I seem to be a little late to the party, but here is my 2 cents:

First year seedlings can most certainly produce flowers. 2 out of the 3 plant that I started last year had full size flowers by August of their first year without any treatment.

The idea of inducing flowers on young plants to pick desirable traits is intriguing. However, it may be more difficult than you anticipate. The flavors and acid levels can vary widely between cones on the same, mature plant. Environmental factors such as the amount of sun to the cones can play a big part. I have also personally noticed that the cones from young plants can be very different than cones from a mature plant of the same variety.

It is an interesting idea and I wish you the best. Keep us informed of our progress.

Yes, I had considered that; the fact that they have been toyed with in such a way may result in different phenotypes than would have otherwise occurred. Hopefully, it will not be to an extent that I keep the worst and toss the best! But actually, what I am doing is not at all new; it happens all the time in another community of growers that are very related to hops.

Actually in the coming year, I am hoping to port many of their techniques into Humulus cultivation,

 

[Xier]

... I have also personally noticed that the cones from young plants can be very different than cones from a mature plant of the same variety. ...

I just thought of something to ask you: were the differences consistent? That is, were the early cones from different varieties different from the mature cones in the same way?

For example: the early cones were all more astringent or all had less bitterness or something else.

Or, were the differences seemingly random from variety to variety?

 

[nagmay]

In my experience (others, feel free to chime in), cones form the young plants seem to consistently produce low acid levels. This can make it hard to identify flavors and final alpha/beta percentages. The problem is, that I don't believe that the acid levels are a direct correlation to levels of the mature plant ... that is, 2 plants side-by-side could both have 3% the first year, but when mature one might have 3.5% and the other 14%.

However, this is based on my personal observations. I haven't done any scientific testing to back it up.

Overall, I don't believe that testing the young plants would steer you in the opposite direction. It just probably won't give as much information as you might be hoping for.

 

[B-Hoppy]

I've seen tremendous variability over the years in the vigor of first year plantings from rhizomes. Some take right off and produce a decent crop while others just seem to struggle, and those hops have very little lupulin (which never seems to develop that deep color of the lupulin from the cones from a mature plant), sometimes with almost no aroma at all. After that 'establishment year', they most alway show the same vigor of the ones that did well during the previous year. Just some observations.

 

[nagmay]

But actually, what I am doing is not at all new; it happens all the time in another community of growers that are very related to hops. Actually in the coming year, I am hoping to port many of their techniques into Humulus cultivation,

Speaking of which... I hear that vaporizing the hops is a great way to test for flavor (jump to about 50 sec): [ame]https://www.youtube.com/watch?v=t5xWQOIJk9k&start=46[/ame]

Anyone try this before?

 

[brewerelated]

Speaking of which... I hear that vaporizing the hops is a great way to test for flavor (jump to about 50 sec):[\quote]

When you said vaporize I thought they were just going to vaporize them and smell them. I didn't know these guys were gonna smoke hops. I don't know for sure they were smoking it, but it looked like they were.

I love Lagunitas IPA. It was the IPA that got me into IPAs. I have since moved on to stronger IPAs, but they make a good introductory IPA.

 

[brewerelated]

Interesting, I hadn't heard of the dwarf varieties before. What I will probably end up doing is setting up a grow room first and posting pictures online. When everyone sees the setup and gets interested, I will ask them to donate seeds for the experiment. It won't be till later this year though.

Check out this thread:

https://www.homebrewtalk.com/f92/so-you-want-breed-your-own-hops-464503/

Most of us that are working on breeding hops have gather in this thread. We have been supporting each other with our findings and with seeds/rhizomes.

 

[Xier]

... I don't believe that the acid levels are a direct correlation to levels of the mature plant...

I am mainly aiming to breed aroma varieties so maybe that won't be too much of a set-back. As they say, time will tell.

...Some take right off and produce a decent crop while others just seem to struggle, and those hops have very little lupulin (which never seems to develop that deep color of the lupulin from the cones from a mature plant), sometimes with almost no aroma at all...

If that is the case, it actually wouldn't be too bad; it would cause a bottle-neck, but all that pass through should be fairly gradable.

Speaking of which... I hear that vaporizing the hops is a great way to test for flavor...

I was thinking about smoking them to assess flavour, vaping seems a better alternative though. The video is blocked here, so I can't watch it.

Check out this thread:

https://www.homebrewtalk.com/f92/so-you-want-breed-your-own-hops-464503/

Most of us that are working on breeding hops have gather in this thread. We have been supporting each other with our findings and with seeds/rhizomes.

I have been following that thread; it is very interesting what you are all doing.

 

[Chronobotanist]

I'm glad I found this thread. I'm thinking about growing hops this year and wanted to know the flowering response in hops.

Just to add in my 2 cents, I'm a researcher and I work on the genetics and molecular biology of the photoperiodic flowering responses in the model plant Arabidopsis. Controlling the flowering response shouldn't be hard but you'll need lights and a dark shed or something like that to strictly control the light cycle. Once they've been induced to flower, the process is largely irreversible so you can put them back outside / in the greenhouse or what have you. If they need vernalization then usually 3-4 weeks from what I've read is enough to induce competency, but that might mean you need a cold room or something depending on plant size.

I might try this on cuttings I got from a friend's plant this summer, so I'll try to keep the thread updated.