Development completed of fully stable and genetically uniform cannabis hybrid seeds
CanBreed has completed the development of a stable and uniform Cannabis hybrid seed. In doing so, the company brings a solution to the main problem of the Cannabis industry that suffers from a lack of uniformity and standardization due to the absence of genetic stability in Cannabis plants resulting also in high production costs that hamper growers’ profits. Stable and uniform hybrid seeds, with improved genetics, are the solution to both these problems.
In June 2020, after more than three years of strenuous research and development, CanBreed completed the development of the first uniform homozygous (100% stable) Cannabis parental lines. Crosses between these parental lines creates the world’s first true F1 hybrids Cannabis seeds. The company has completed the first F1 hybrid seed production cycle in the world. These stable hybrids will ensure the reproducibility, standardization and high quality of raw material for the entire Cannabis industry.
In the present cycle, CanBreed produced dozens of stable new varieties from diverse genetic backgrounds, which will be planted for testing in CanBreed’s breeding and seeds production farm that is at its final stages of construction. At the end of the selection phase, which is expected to be completed during the first half of 2021, the seeds of the varieties that fit industry demands will be marketed.
Unlike most agricultural crops that are grown from stable seeds, Cannabis plants are presently propagated vegetatively through cloning by using cuttings from mother plants. Cloning is done in order to ensure genetic identity between the offspring and the mother plants, which until now could not be achieved by growing Cannabis from seeds because there were no stable Cannabis seeds.
The main cause of the lack of standardization that exists in the industry is that the raw material extracted from Cannabis plants grown from cuttings is not reproducible. On one hand, cloning ensures a genetic identity between the offspring and the mother plant, but on the other hand, the cloning methods that exist today (such as tissue cultures) do not prevent the aging of the mother plants. Thus, similar to the natural aging processes that take place in any living organism (including humans) mother plants accumulate aging related mutations and changes in the genome that cause differences in the chemical profile of the plant. This leads to the fact that despite being genetically identical, the chemical profile of offspring differs from those of the young mother plants.
The reason that until now it was not possible to get reproducible and uniform Cannabis products by growing Cannabis from seeds is that all Cannabis strains in the market today are heterozygous (genetically unstable) and crossing between two unstable Cannabis strains will produce seeds with high genetic variation. Thus, today every seed grown on a plant produced from the crossing of two unstable plants is genetically different from all the other seeds on the same plant. The fact that all the seeds are different from each other in a particular Cannabis plant means that plants grown from these seeds, even though they originated from the same plant, will have a different genetic profile. Therefore, to this day, the only method available for Cannabis growers to preserve the genetic identity of the offsprings has been through cloning of mother plants.
The solution to the problem comes from the seeds industry.
In the agricultural industry, plants, such as tomatoes, corn, watermelon, etc, are grown exclusively from stable seeds thus ensuring genetic uniformity that enables high quality growing and reproducibility of the products.
Stable seeds, such as tomato seeds, corn, etc. used in the agricultural industry, are produced from homozygous parental lines (plants that are 100% genetically stable). The procedure of creating homozygous plants requires dedicated resources, unique agronomic and scientific knowledge and consumes considerable time. Crossing of two different homozygous plants will produce seeds that are genetically identical, meaning that all the resultant seeds of the crossing will have the same DNA (identical twins). These seeds are known in the seed industry as F1 Hybrid seeds. Using F1 Hybrid seeds will always result in plants identical to each other, thus eliminating the need for cloning of Cannabis and Hemp and ensuring the reproducibility and uniformity of the raw material extracted from the plant.
In parallel to the development of stable seeds, CanBreed is developing YieldMaxTM, an enhanced genetic trait platform, which contains all the agronomic traits that Cannabis and Hemp growers need for consistent, high-quality, cost efficient mass-scale cultivation. The breeding of the YieldMaxTM traits is achieved by using CRISPR-Cas9, an innovative gene editing technology. Upon completion of the YieldMaxTM development, the stable seeds of CanBreed will contain also these traits.
At November, CanBreed announced that as part of its project to develop a Powdery Mildew resistance trait, which is one of the traits in the YieldMaxTM platform, the company performed and identified an editing event in the Cannabis plant genome using CRISPR-Cas9. This report follows the company’s announcement on signing a commercial license agreement for CRISPR-Cas9 foundational patents with the CRISPR patent owners – Corteva Biosciences and Broad Institute (of MIT and Harvard). The CRISPR developers were recently awarded with the Nobel Prize in Chemistry for 2020.
The company further announced recently that it had purchased a 3.5-acre farm in San Diego county in California. A production facility of stable hemp seeds intended for the US market is planned to be set-up at the farm. The farm’s initial output is expected to be about 12.5 million seeds annually, which will subsequently increase to about 50 million seeds annually.
Ido Margalit, CanBreed CEO: “The company’s achievement comes after nearly four challenging years of development as the company faces extensive knowledge and infrastructure gaps in the field of Cannabis seeds, and in parallel invests in market education regarding the feasibility of developing stable Cannabis and Hemp seeds. CanBreed’s achievement, first of its kind in the world, positions the company at the forefront of this emerging industry that will provide a solution to a huge global potential market of Cannabis and Hemp seeds, estimated at hundreds of millions of dollars a year”.
Why Not Save Hybrid Seeds?
Upon paging through a seed catalog, one can’t help but be impressed with the number of times the term “hybrid” is used. More and more vegetables (and flowers) are available as F1 hybrids. The cost of hybrid seed is equally impressive, prompting some frugal growers to attempt to save the seeds of hybrids for next year’s crop. The result usually is very disappointing; the following article will attempt to explain why.
By definition, a hybrid is simply the offspring that results from the mating of two individual with dissimilar genetic makeup. A more restrictive definition of hybrid is an individual that is the result of a cross between two inbred parents. The result, called a F1 hybrid, was created to exploit the phenomenon of hybrid vigor (or heterosis, as it is scientifically termed). The advantages of hybrid vigor include improved vigor, higher yields, earlier maturity, greater uniformity and an increase in the expression of certain traits.
In this day-and-age of being able to map the entire genetic make-up (genome) of plants and animals, scientists still are at a loss to explain why hybrid vigor occurs. A bit of genetics is required to explain this phenomenon further.
Most plants genetically are diploids meaning they have two sets of chromosomes–one from their male (pollen) parent and one from their female (egg) parent. Contained on these chromosomes are the genes responsible for the expression the various traits of the plant. When the gene(s) for a trait are the same on both the chromosome inherited from the pollen parent as that from the egg parent, the individual is said to be homozygous for that trait. Inbred plants are homozygous for all genes on their chromosomes.
Conversely, when the gene(s) are different the individual is termed heterozygous. For example, fruit color in tomato is controlled by the action of a single gene. Every tomato has two genes for the fruit color trait, one from each of its parents. Genetically, if we assume ‘R’=red fruit, ‘r’=pink fruit and red is dominant over pink, tomatoes with the genetic makeup of ‘RR’ and ‘Rr’ would both have red fruit. The former would be called homozygous for the gene (both genes are the same) for fruit color whereas the latter would be heterozygous (the genes differ). Since the (recessive) gene for pink fruit can only express itself in the absence of the (dominant) gene for red, pink-fruited plants genetically would be ‘rr’ and also homozygous.
We can use the above to illustrate why F1 hybrids do not “breed true”. If a homozygous red-fruited breeding (RR) line were to be crossed with a homozygous pink-fruited (rr) breeding line, all of the F1 progeny would be Rr for fruit color and bear red fruit, since red is dominant over pink. However, when the heterozygous F1 pollinates itself, the result will be both red and pink fruited F2 plants in the ratio of 3 red for every 1 pink. The latter ratio was derived in the mid- 1800s by Gregor Mendel, who was one of the first people to study the inheritance of traits in plants.
Most economically important traits (e.g. vigor, yield) are controlled by the action of many genes. Some geneticists believe F1 hybrids are superior because they contain all of the favorable genes for a trait held by both of their parents. But, if this were true then at least some of their progeny should equal their F1 hybrid parents in performance, and this is not the case. Others believe it is the fact that corresponding genes for a trait are in a heterozygous state (differ from each other such as the ‘Rr’ red-fruited tomato) in the F1 hybrid when compared with either parent, but there are faults with this theory as well.
The method used to develop hybrid parental lines depends on whether the crop in question is self-pollinated or cross-pollinated. Self-pollinated plants such as tomato are high homozygous, as described above. Therefore, crossing any two inbred (e.g. heirloom) tomatoes will result in the production of F1 hybrid seed. However, in an attempt to form inbred breeding lines with numerous good traits, tomatoes are often crossed to form potential breeding lines. Seed is then saved from plants that possess the favorable traits from both parents. This must be done for six generations before the breeding line is considered to be homozygous and a good prospect to serve as a parent in the production of an F1 hybrid.
In contrast, cross-pollinated crops such as sweet corn are highly heterozygous. In order to form parental breeding lines, controlled self-pollination must take place for at least six years to form homozygous individuals. Each and every generation of self-pollination results in the loss of plant vigor making the parents of hybrid cross-pollinated plants unproductive, adding to seed cost. Fortunately, the vigor is more than regained in the F1 hybrid.
Suffice to say however they are produced, F1 are worth the added seed cost. Their development is painstaking and expensive. Many, many crosses must be made and evaluated before the plant breeder is likely to find a combination of parents that lead to an improvement for the trait(s) under improvement. Pollination must be strictly controlled and often is still done by hand in naturally self-pollinated species. Once a favorable combination of parents has been identified, the cross must be made each time seed of the F1 hybrid is wanted, since hybrid vigor only last one generation. Again, if the crop in question is self-pollinated this very tedious, time-consuming process must be done by hand.
When seed is saved from F1 hybrids, the resulting progeny tend (genetically) to revert back to the parents that were used to make the cross. The result is a loss of hybrid vigor and its benefits, along with disappointing performance. Again, it is important to remember that hybrid vigor lasts only one generation and results only when two parental lines are crossed. Therefore, saving the seeds from hybrids is not recommended.
Editor’s note. In 2013 I had some ‘volunteer’ tomatoes come up where the F1 Hybrid ‘Sunsugar’ was growing in 2012. I also had a Sunsugar planted in 2013 elsewhere in the garden, so I could compare the progeny to it (I termed it Sunsugar and ‘Son of Sunsugar’). The fruit was yellow, of similar size and really quite good, but not as sweet and not quite as tasty. The Sunsugar fruit had a somewhat translucent shine where ‘Son of Sunsugar’ was a bit opaque. I had these at MU Bradford Farm’ annual ‘TomatoFest’ and a number of individuals tried them and agreed, the F1 fruit was better than the progeny. I had no ability to evaluate vigor or anything else.