550 Grasses and Leguminous Crops in New York 



are now in progress to determine the amount of this variation. 

 But in general, the clons (cuttings) from a single parental plant 

 are quite uniform, and they furnish an eixcellent means for a 

 more complete study than can be made of one individual plant. 



Environment is a very important factor in the development of 

 any plant. Considerable variation may be produced by changing 

 the environment. Such variation is not inherited and is of no 

 practical value to the plant breeder. On the other hand, there are 

 variations that are inherited, or, as we sometimes say, that come 

 true to seed. In order tO' make intelligent selections, the experi- 

 menter must determine which variations are transmitted to the 

 offspring. 



In order to study the transmission of these diffei-ent types, 

 inbred seed was obtained by covering a bunch of heads with a 

 paper bag before blooming time (Fig. 603). This inbred seed 

 was carefully germinated in plats of sterilized soil, and the young 

 seedlings were transplanted to the field. Twelve or fifteen seed- 

 lings from each parental plant were planted in a single row. The 

 rows were three feet apart and the plants were thirty inches apart 

 in the row. By thus comparing the plants of a single row with 

 the parent plant and with each other, it was possible to observe to 

 what extent the characters in question were transmitted. In this 

 test were included a large number of promising hay types, as 

 well as many others of no apparent value, the latter being included 

 for their scientific interest. 



I^ot all of the varying characters observed in the original selec- 

 tions were inherited, but there have been more than two hundred 

 definite types 6f timothy isolated. Figs. CO-1, 605, and 606 are 

 reproduced from photographs of some of these individual rows. 

 The uniformity of the plants within the same row is striking, but 

 not more so than the diiferences between the individual rows. In 

 these instances we know that the differences are due to the nature 

 of the variety or type and not to variations in soil or treatment, 

 for the treatment was miiform for all the rows and between any 

 two neighboring rows there was only a space of three feet. Yet 

 the type of plants is remarkably different. 



As soon as tjie seed transmission of desirable types wasi deter- 

 mined, the next thing in order was to increase the seed of the 



