Colchicine and Polyploid Breeding

This post is a follow up to a post on colchicine use. If you have 100 seedlings and apply chemicals like colchicine or dinitroanilines to induce polyploidy, you could get a single super spectacular specimen of plant that grows faster, yields more and is over all more vibrant. However, why does not everyone do this? Maybe it is hard to get colchicine? The only use I found it for is treatment for gout. I have read colchicine is toxic so that alone may be a reason not to use it. I have not found any studies examining if it can be metabolized by plants. What this means is if plants cannot break it down, colchicine will remain in the plants, similar to how heavy metals can remain in the body for long periods of time. This means if you consume the plant, you may consume colchicine too.

Acquiring colchicine and potential health risks aside, the first thing one could expect is to lose 50% of the seedlings minimum. That is 50% of your money for seeds down the tubes before you get started. It might be possible to take several clones and try it on established clones if you pay a lot for seeds. Several changes in the plant result from induced polyploidy. These changes are due to changes in the genetic composition. Some (not all) of these changes will result in bigger, better plants. In general, polyploidy results in increased leaf and flower size (which can be seen in increased cell size and chloroplast count). These changes are sometimes referred to as the gigas effect. This gigas effect has found application in the breeding of medicinal herbs in the production of pharmaceuticals. Hybrid vigor resulting from interspecific crosses in allopolyploids is one of the most common ways crops are being improved today. These genetic traits/changes will not always remain in later generations. Once plants become polyploids, they begin to undergo changes to make their chromosomes more like pairs of chromosomes. This is called diploidization. There are a lot of reasons plants do this one reason might be to lead to increased fertility

It seems that how one gets a super spectacular specimen of plant, is not just soak seeds in magic juice. Many plants like strawberry and blueberry have naturally occurring polyploids, and these plants are then bred for specific traits. (read this post on plant breeding) As I wrote on the polyploid post, the benefits of polyploidy is not from doubling the chromosomes. Ferns for example often have 100-200 chromosomes whereas corn has 20. The number is not important; it is the GENES on the chromosomes that matter.
So, if you have gene A that gives big flowers, (or any trait you want) you could have a triploid with three copies (AAA) or tetraploid with four (AAAA) instead of the normal diploid AA. The more A genes a plant has, the bigger its flowers. Most likely there is a limit to how much improved growth you get with just more A’s. Today, most crop polyploids have a mixture of genes for flowering (or other traits). When you have two different genes that increasing flowers say A and B the two genes in multiple copies give a synergistic effect compared to just a percentage of increase you get from adding more the same gene. In other words having AABB is better than AAAA or BBBB. To combine different genes like AABB, you get the A and the B together by breeding. Just like F1 hybrids are awesome b/c they have great genes from two parents, Polyploids are usually found to be better with combinations of good genes for a trait. The term for this improved growth due to a mixture of genes is heterosis
Most experts take years to get a single super spectacular specimen this way. Is it possible? Yes. Is it easy and cheap? No. I wanted to let the readers know it is possible, but there is A LOT of complicated stuff involved. I am pretty sure you just can’t soak seeds of a crop and get some super freaks. But then again, that is why science is needed, to prove things. If anyone has any first-hand experience, please E-mail me or leave a comment
Good Growing,
Dr E.R. Myers

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