Originally Posted by DutchHempCBD
- Does the pollination of the female hemp flower lower the percentage and/or amount of CBD in that flower? Am I correct in assuming that a part of what could have been flower material with high CBD content is transformed into seeds with very low CBD content? And so in pollinated flowers the total amount of CBD is lower as opposed to unpollinated?
- Am I correct in assuming that choosing for a dioecious variety enables more control over avoiding pollination as opposed to a monoecious variety? At the stage that sex differentiation takes place males can be taken out manually in a small scale agricultural setup. If female and male plants arise 50/50 ratio this results in sowing at for example 50 kg/ha. In doing this the targeted density of 25 kg/ha of female hemp flowers is reached.
- Could there be an advantage in choosing a monoecious variety with a high female predominance (e.g. > 85% female and < 15% monoecious and/or males). Some variety similar to the Canadian hemp variety Alyssa (though not EU certified…)? In that case only 15% or less of the plants have to be removed manually.
Regarding your questions:
1: Yes, it will lower the yield per acre because unseeded hemp produces large amounts of new flowers (aka sinsemilla) thereby increasing the harvest yield and total CBD. Although, the amount resin per gram flowers may remain the same; it's not so clear and lacks solid data.
2: Correct. True monoecious will lead to complete pollination but with dioecious already one single male may pollinate your whole batch! Culling males is possible but VERY laborious. It has been done in the early hemp breeding programs but they went to unisex plants. Maybe you can get true unisex plants (this are the F1's of dioecious females with monoecious plants as pollen donors)? Though, seems to me as if the F2 seeds are the ones sold for fibre production ;( . Still, culling a few males is way easier than 50%. Also, you'd have to buy only half the seeds
3: Correct, see point 2. Most French varieties belong to this group. I couldn't find hard evidence for the statements about the exact amount of females in these hybrids. Sometimes it's mentioned female predominant, sometimes 50:50... the few males in true female predominant crosses are often from stray pollen from true males forgotten to cull in the process.
You may have a chance with Finola and other seed hemp varieties because the males mature well before the females; in part a wanted trait because that way the males are gone once the seeds mature and it gets easier to harvest. Other varieties, especially the pure fibre types, mature together so that you don't waist good male fibres and there you'd have trouble culling the males in time
Something else to consider:
It is often stated that this and that variety contains high amounts of CBD (like Finola and Carmagnola). I don't really believe that they contain a lot, it's at best a bit more than others. Apart from the varieties bred for super low cannabinoid content, hemp contains more CBD than THC but as you know only a few % in total. With some varieties like Finola and Carmagnola you have to be careful: The THC content is really limit and increasing CBD will also increase THC... but you won't do selective breeding over several generations, right?
BTW Eastern European varieties are often tall fibre plants not suited for Dutch climate but rather for Italy and Spain.
Go with French varieties if you like monoecious ones. From what I've seen, you can only get seeds of these in France even if some dioecious ones are registered: The latter are likely registered because they are used in breeding of hybrids.
Current German varieties seem to be very low in overall cannabinoid content (like many French ones too) and often monoecious too.
Canadian ones (some are Finola crosses, BTW) might be nice in terms of climate and maturation but the legality in EU...
Besides, did you realise that the numbers in the names of most varieties indicate maturity and/or flower onset? That said, go for low numbers!