Does seed propagation produce bad seedlings? I read that clones are superior.
Seed propagation does not produce bad seedlings! You just may not get the seedling you want. Genetics phenotype is the real question, not the health of the seedlings. With seed, you have unknown traits that will not be discovered until five to 20 years later. With clones, nothing is unknown. You have an exact copy of the mother tree. Tissue cultures are nothing more than clone trees that have been replicated through micro-propagation. The old fashion method of cloning is to use root cuttings.
For example, some people want to grow the Paulownia trees slow for the Japanese’s markets; you do not want a tree that has “superior growth.” You would want a tree to have the genetics to put most of its energy into seed production not wood production (slow growth). This way the annual growth rings average 6 to 8 per inch.
You may want a tree that has a higher resistance to sun scald damage, or is more tolerant to high clay content and poor drainage, or drought, or has more terminal growth. You need to know what the clone’s better edge is before you buy!
As for seed, there are three things in its favor:
- Seeds are cheap! For investments, the less money used in the initial investment, the easier it is to make a profit.
- You get variance in the genetics. If planted thick, the trees most suitable for the site by natural selection and your needs can be selected as they grow. The others would scum to your saw.
- Since you started them form seed, you control their health. There are no issues with damage during the shipping process. You can get very healthy seedlings!
I have raised both types of seedlings. What I have found is my seed have both underperformed and outperformed Paulownia clones. Most of the time, quality seed trees tend to produce quality trees, which equals that of the Internet's “superior clones”—or even sometimes surpasses them. I have found that excellent site selection and preparation impacts performance the most.
The point I wish to make is this: Most Paulownia has the genetic potential for fast growth in the early years, but genetics is not the most important factor. Site selection (soil depth, drainage, orientation with the sun, and wind protection) is just as important for good growth rates, along with length of growing season, fertility, moisture, and weed control! The reason for the poor growth in the left picture is the soil.
In the picture on the left, the top soil is deep and loose. In the second picture, the top soil was little, with a hard pan underneath.
In summary, if your Paulownia does not grow as expected, it may not be the tree’s fault! Paulownia are very site-sensitive. Any site that is less than ideal will have dramatic effects upon growth rates. I only got 18 inches for this clone elongata. Good genetics does not fix a poor site!
The bottom line: If you go with clones, be sure the mother tree is “superior” for your specific needs and those need justify their high cost! The low cost of seed makes it easier to make a profit. If you are not sure, start a test plot from seed. After the trees show themselves, pick the ones you like, dig some of their roots when dormant, and voila! You have their clones. Return of investment is the real question.