Inconstancy of Improved Races 781 



size of the grains decreases, the total amount 

 of nourishment available for all of them 

 remaining, about the same. Thus the 

 kernels and consequently the new plants be- 

 came smaller and weaker, and the chance 

 of fertilization was diminished, in the ears 

 with the highest number of rows. Conse- 

 quently the choice was limited, and after having 

 twice chosen a spike with 20 and once one with 

 24 rows, I finally preferred those with the inter- 

 mediate number of 22. 



This repeated choice has brought the aver- 

 age of my race up from 13 to 20, and thus to the 

 extreme limit of the original variety. Seven 

 years were required to attain this result, or on 

 an average the progression was one row in a 

 year. This augmentation was accompanied by 

 an accompanying movement of the whole group 

 in the same direction. The extreme on the side 

 of the small numbers came up from 8 to 12 

 rows, and cobs with 8 or 10 rows did not appear 

 in my race later than the third generation. On 

 the other side the extreme reached 28, a figure 

 never reached by the original variety as culti- 

 vated with us, and ears with 24 and 26 rows 

 have been seen during the four last generations 

 in increasing numbers. 



This slow and gradual amelioration was part- 

 ly due to the mode of pollination of the corn. 



