Breeding

The long view on genetic progress

One of the major pitfalls in breeding programs is allowing your genetic base to become too narrow. Over time, a breeding program tends to focus on the most advanced and productive lines, while ignoring those that are further from commercial quality. It can be productive in the short run to have this focus, but in the long run it results in the limitation of further genetic progress. 

For this reason, I have been somewhat surprised by the rules established in Oregon and Washington that will make each state into genetic 'islands'. The rules state that after a short introductory window, all seeds and clones must be purchased from other producers within the state. I understand the motivation behind this (a conservative interpretation of the Cole memo), but if the rules remain the same for more than a few years, it will create a problem for growers:

As new, improved varieties are developed outside their home state, they will be faced with either becoming noncompetitive, or breaking the established rules to acquire new varieties. I don't like to see non-sustainable systems created. 

If we are lucky, within a few years legalized states will be able to initiate reciprocity agreements that will allow, at a minimum, the exchange of breeding material. 

As for NBS, we are collecting as much germplasm as we can for our breeding program. We will maintain as much of it as possible, to ensure that we have the ability to continue making genetic progress for many years to come. 

The messy realities of breeding

Cannabis cultivars are often advertised as being 'Indica', 'Sativa', or some blend of these (even getting so specific as to claim something like 20% Indica / 80% Sativa). Cultivars are advertised this way as a result of the commonly held belief is that 'Indica' cultivars have relaxing effects, while 'Sativa' cultivars are more energizing and cerebral.

Unfortunately, inheritance does not work this way. 

While I believe that the effects of different cultivars vary depending on cannabinoid (or other secondary metabolite) content, the truth is that the 'Indica'/'Sativa'  dichotomy is little more than genetic hocus-pocus.  

They say with every legend there is a grain of truth, so perhaps we will start with what MIGHT be true.

  • It is possible that pure Indica and Sativa cultivars each have a distinct chemotype that also has unique effects. 
  • It is possible, depending on the inheritance of the chemotype, that an F1 hybrid made between a pure Indica and a pure Sativa would have a chemotype (and effect) intermediate between the two. In addition, a breeder could reliably claim that the hybrid was 50% Indica / 50% sativa. 

But things fall apart after that. Any additional work with that 50/50 plant opens Pandora's box. Chromosomes segregate independently, and recombination between chromosomes may occur. If you cross two of the 50/50 plants you could theoretically get a pure 'Sativa', pure 'Indica', or anything in between. The only way to know the background of a given plant would be to test a lot of genetic markers, as was done by these researchers.

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0133292#pone.0133292.ref007

Look at part 'b' of this figure. The colored column shows the actual percentage of Sativa (red) genetic background as determined by molecular markers, vs the reported background in numbers. There is only a weak relationship between the advertised background and the actual background. 

On a more alarming note, the same research found that in 1/3 of cases, cultivars with one name were most similar to some other named cultivar.... meaning that the consumer has little idea what they are purchasing based on name alone. 

Furthermore, the  genetic background is mostly irrelevant to the chemotype once the breeding process begins. What really matters are the specific genetic loci that control the chemotype. These loci are unknown in number and location, but could be inherited independently of the majority of the genetic 'background'. In other words, a savvy breeder could create a 99.99% 'Indica' background cultivar with a full 'Sativa' chemotype. 

I would encourage consumers to pay attention to the results from analytical labs, and their own bodies, and avoid buying into simplistic genetic explanations.  

Here is some more information on cannabis chemotypes for those interested in the subject.