150 PLANTS AND MAN 



began taking plants from their natural environment and growing 

 them in his fields and gardens. Only those wild plants were 

 transplanted which possessed the most desirable variations in 

 their edible or otherwise useful parts. Some of these variations 

 were found to be due to environmental conditions — such as 

 amount of humus in the soil, available moisture or light; plants 

 with such variations had no value as parental stock for cultivated 

 plants, since such variations were not inherited by the offspring. 

 At the same time, other variations were found to be produced 

 independently of the environment, and to be repeated in the 

 offspring. Thus when the early cultivators of plants also learned 

 the other fundamental biologic truth that offspring tend to resem- 

 ble their parents and to perpetuate their characteristics, they 

 were well on their way to making plant breeding a science; even 

 though this was centuries before the time of Mendel and the 

 knowledge of chromosomes and genes. 



The appreciation of the occurrence of variations which were 

 heritable led to the careful selection of those wild plants whose 

 fruits or other parts varied the most in the desired direction. 

 Tubers, cuttings or seeds of these were chosen to start the 

 cultivated race; and from these only the best were chosen to 

 propagate the next season's crop. Such a process of selection — 

 first from the wild plants and then year by year from among 

 the cultivated ones — led to the elimination of those individuals 

 with undesirable variations and to the perpetuation of those 

 with the desirable qualities. Such selection, at first unconsciously 

 carried out, has been the chief method by which man has 

 produced his cultivated plants. In more recent times it has been 

 carried out consciously and scientifically. 



Scientific methods of selection began in the early part of the 

 nineteenth century. One of the first to carry out selection on a 

 scientific basis was a gentleman farmer named LeCouteur who 

 grew wheat on the Isle of Jersey. Becoming interested in pro- 

 ducing a more uniform crop with more desirable grains, he 

 began systematic selection from the varied assortment of plants 

 in his wheat field by separating the seeds of plants with differing 

 characteristics (such as height, size of grain, strength of stems, 

 etc.). These seeds from plants with uniform characters were sown 



