The Monthly Review : 269-270 (November 1809)
Hints respecting the proper Mode of inuring Tender Plants to our Climate.
By the Right Honourable Sir Joseph Banks, Bart., &c.
Mr. Knight's principle of giving hardihood to plants which came originally from a warm climate, and of training them gradually to bear the severity of our own, by propagating not from suckers but from seeds, through a number of generations, is here very well illustrated:
'In the year 1791, some seeds of Zizania aquatica, were procured from Canada, and sown in a pond at Spring Grove, near Hounslow; it grew, and produced strong plants, which ripened their seeds; those seeds vegetated in the succeeding spring, but the plants they produced were weak, slender, not half so tall as those of the first generation, and grew in the shallowest water only; the seeds of these plants produced others the next year sensibly stronger than their parents of the second year.
'In this manner the plants proceeded, springing up every year from the seeds of the preceding one, every year becoming visibly stronger and larger, and rising from deeper parts of the pond, till the last year, 1804, when several of the plants were six feet in height, and the whole pond was in every part covered with them as thick as wheat grows on a well managed field.
'Here we have an experiment which proves, that an annual plant, scarce able to endure the ungenial summer of England, has become, in fourteen generations, as strong and as vigorous as our indigenous plants are, and as perfect in all its parts as in its native climate.'
This experiment is encouraging, and by a subsequent paper our hopes are strengthened.
Note: Compare with what Allen (1902) wrote about adaptation of Canadian corn:
"Corn has been and is being grown to a profit where there is rarely a month in the year without a frost. I have seen it growing in the province of Quebec where such climatic conditions existed. The stalk did not exceed more than four feet in height and was proportionate in diameter, yet nearly all of them produced each two small ears of sound yellow corn of most excellent quality.
"Some of this corn was taken to central New York and given every attention necessary for the production of a crop, and never did plants respond more freely to good treatment. The growth was no larger than the same made in Quebec, and the harvest was made in about the same number of days after planting the crop, being harvested before the middle of August.
"The seed product was all used for planting the following season, but its consciousness having found that in the climate of its adopted home it had twice as long a time to mature, it took it all and grew as high and strong as the yellow flint corn there generally grown, and produced as large ears. Its identity as an early type or variety was lost, but the lesson taught was instructive and valuable, showing how readily the plant adapted itself to the conditions as found and how readily all plants accept the situation given them and cheerfully perform their alloted work."
In both cases, the plants growing in the new habitat the first year duplicated the growth of their parents. But in the second generation, the plants changed.