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Cannabis Breeding Indoors – Male Selection

Cannabis Breeding Indoors – Male Selection


There are a lot of reasons for breeding cannabis indoors. Connoisseurs especially have good reason these days, with the true diversity of cannabis disappearing, in my opinion, with commercialization. Where would Joe Blow go to get some real Thai these days? I have tried a few of the supposed Thai lines that are commercially available, and as someone who knows real-deal Thai, those aren’t it baybee.

Making Seeds Full of Genetic Potential to Rock Your Grow Rooms

Also, you want to be able to create the ultimate hybrid, for terpenes, yields, resin production, potency, and high-type. Male selection is a critical element here—duh. I’m going to try and add some game to your breeding adventures today, with some awesome male selection advice for both beginner and advanced cannabis breeding alike.

I use Thai above as an example. Inbreeding is fairly easy with good solid genetics, but you always want to be making the genetic line better and better as you inbreed it. That’s why the selection is so important. Females are easy, compared to male selection. Selecting males has some serious subtleties involved, and some cool shortcuts available too. Let’s get cracking…

Selecting Well from the F2 Generation When Inbreeding is Magic Time

First Things First

You must actually be a (consistently) good grower and have a primo well-controlled environment indoors before you should attempt competent selection. Don’t go with some new product(s) you are unfamiliar with while male selection is your mission. Otherwise, you will likely be FUBAR, and your offspring generation will have issues. Let me share some things you need to have dialed first.

  • Quality, dependable, and intense lighting is a must-have.
  • Digital timers are a must-have; and, your photoperiods must be pitch black dark during lights off, even during sprouting and vegetative states. Very important!
  • You need to be aware of temps and humidity ranges over a 24-hr. period. You can get these instruments inexpensively everywhere, online, Wallyworld, etc.
  • Your air circulation must be tip top awesome. You must have a good moving air current always rocking your selection area(s) and breeding room(s). Along with primo air exchange, of course.
  • You will need a 20x Jeweler’s Loup—seriously, 20x is the sweet spot here, trust me.

We are simply removing some variables with the above list. Unknown variables are your worst enemy here, and while we can never know them all, what we can do is play into higher percentages of success by leveraging what we do know. Cannabis breeding for male selection is an art, and a science.

A Neat Shortcut for Male Selection

Cotyledons—boom! These are the little round leaves that pop out when the plants first sprout. After they are above ground for a few days (label them with numbers) you will want to examine all the cotyledons of all the sprouts with a 20x Loup. What you will be tracking here is leaf hair density. You will see all the leaf hairs on the cotyledons clearly with the 20x magnification.

This is the Time to Examine the Cotyledons

You want to rate which sprouts have cotyledons with the densest formations of leaf hairs. Cotyledons are reliable here in my experience for this. A normal cannabis leaf can differ in hair density from leaf to leaf. The cotyledons’ leaf hairs are a good benchmark that represents genetic expression potential before the environment has become a big factor.

Leaf Hairs and Trichomes are the Same Things Essentially

Leaf hairs and trichomes are basically the same things. So, for superior resin production (and terpenes) in your offspring, you want your males to have the genetic potential to donate those properties; denser trichome formation means increased resin production. Keep notes of the plants, by their numbered labels, so you know which ones have the highest leaf hair density. Once you sex them, you will have that info for all your males for cannabis breeding selection.

Sexing Must Happen at the 30-Day Old Mark, Only

The first-time plants express/show their sex is when you want to label them male or female. This always will happen right around the 30 to 40 days above ground mark. It’s very important for TRUE male selection, to do this at this point because cannabis has a way of being able to change the sex of some plants along the way. Under what the plant deems as unfavorable environmental conditions, it will normally switch a lot of females to males. Under the “Garden of Eden” environmental conditions cannabis will switch to higher female ratios.

Super Important to Select True Males at the 30-Day Mark

Some males can become females. Some females can become males. However, right at the 30-day mark or so, plants that show male will always stay male—these are solid males in my experience. Males that show later in a vegetative state, or don’t show at all until the flowering time, are not males you want to breed with normally, in my experience. Here’s how we do…

Sprout seeds on a 12/12 photoperiod under good lights. Once they have been above ground for 10 days switch their photoperiod to 18/6. Use your 20x Loup here and start looking them over closely every day starting from the 30 days above ground mark. It won’t take more than a few days or so to find the males in the bunch. The good ones. Now just select those males to work with, keeping a special eye on those with the highest leaf hair density ratings. Ya with me? You can “weed out” any males with super low ratings at this point, no worries. Breeding cannabis for male selection does have shortcuts.

See Also
The Churn

Hybrid Males are a Tad Trickier than IBL Males to Select Well

Further Male Selection Information

Smelly males are always a good thing. Once they are about 30 or 40 days old you can gently rub the stems a little on the males and take a smell. Smellier males are very often “potent” males with high resin production potential, not always, but usually.

This Male Even Had Super Smelly Pollen

Once your males are about 45 days old, you will want to let them go a bit longer in containers that are a little too small for them. Not rootbound, but getting there. At this point you want to let them dry out until their leaves droop, losing turgor. Then water them and bring them back to happy. Watch them closely for the next two weeks, if they start to flower a little (yes even under 18/6) bit, then go back into a vegetative state, these are acceptable for your male selections. If they full-blown start flowering with no signs of stopping, I would always cull/kill these males. The ones that don’t start flowering at all under an 18/6 photoperiod are your prime male selection candidates right there. This ensures the sexual health of your male selections.

Some Males About to Get the Drought Treatment

There are a lot of other things to look for, vigor, overall health, size, node distance, resistance(s), hollow stems, etc. When you finally have your males, have at least 3 males as your final choices to breed with. You can clone these then flower them to see which ones have the biggest yields, keeping only the biggest yielding one(s). You can also just throw the males all in there, and just before they start throwing pollen you can see which males will have bigger yields, so you can eliminate the others. Ya gotta be good to do it this way, heh heh. L8r G8rs.

  • Revski ????

Rev’s Crossword Time – A New Crossword

A fast and fun little crossword about cannabis-related things. Check it out and take the challenge!