LECTURES AND ESSAYS. 441 



plants are self-fertilized, and all the crosses are between near relations, 

 because all spring from the same stock. 



Tessier in France, and Col. LeCouteur in Jersey, have both made elabo- 

 rate experiments to ascertain if any evil effects arose from this close breeding. 

 Both reach the same conclusion, namely, that with care given to the selection 

 of seed no decrease in vigor or productiveness results, even after a term of 

 years. LeCouteur recommends, however, a rotation of manures and a change 

 of soil, if possible within the limits of the farm. 



Mr. Darwin is very positive in his statement that self-fertilization is injur- 

 ious. But he adds, " Whether the evil from self-fertilization goes on 

 increasing during successive generations is not as yet known, but we may 

 infer from my experiments that the increase if any is far from rapid." He 

 attributes the maintenance of vigor in those cases where plants have been 

 grown for a long time from the same stock, to a previous cross, the effect 

 of which has been transmitted through all the generations. 



The subject of close breeding in plants needs further investigation before 

 definite law can be laid down, but practical experience seems to indicate that 

 with all farm crops it can be carried on indefinitely without injurious effects 

 provided due attention is given to seed selection. Some writers maintain 

 that grain crops are bound to deteriorate unless the seed is frequently 

 changed. Their assertions are based upon the facts that varieties do under 

 common treatment deteriorate, and that change of seed has proved of benefit. 



They generalize from insufficient data, and without the support of experi- 

 ments. We now have abundant evidence that varieties can be maintained 

 and even improved by due care in saving seed, and when a farmer has varie- 

 ties well suited to his soil and climate, his safest plan is to adopt a syste- 

 matic selection of seed, and thus breed up strains that answer all his 

 requirements. 



CLIMATIC LIMITATIONS. 



There are however cases where change of seed is desirable or even neces- 

 sary. They arise from climatic influences. Climate, as you know, limits the 

 range of dent corn. Southern dent corn when taken north, if planted 

 within limits that will allow its ripening enough for seed, will rapidly change 

 its character; the stalk becomes shorter, the kernel loses the dent and 

 becomes rounded, it ripens earlier, and in a very few years it is transformed 

 into a variety resembling the native corn in all respects. On the other hand 

 the eight rowed flint corn if removed south will transform itself into dent. 

 Now, there are localities in our State, lying on the border between the 

 natural homes of flint corn and dent corn, where the dent corn is the more 

 profitable of the two, but under the influence of climate it gradually loses 

 the characters that distinguish it, and it becomes necessary every three or four 

 years to obtain fresh stocks of seed from the more southern counties. This 

 is the practice of many farmers of Kent and other counties having similar 

 ranges of temperature. 



The oat plant delights in a cool, moist atmosphere. At the north it yields 

 larger crops, weighing more pounds to the bushel than it does south, and 

 seed of these northern oats taken south, will the first year yield more and 

 heavier oats than those from native seed. The second year there is a falling 

 off, and soon they will be no better than the old stock. Hence the practice 

 in many localities of obtaining seed oats from higher latitudes. 



