448 Plant-Breeding 



Materials. Ten ears of different races and types of corn to 

 each student ; tape, scales, charts, etc. 



Each student should score a sample of flint corn according to 

 the following score card : 



New England Flint 



POINTS 



Maturity and seed condition 20 



Uniformity (or regularity of single ears) 15 



Kernels 15 



Weight of ear 10 



Length and proportion 10 



Tips 5 



Butts 10 



Sulci (space between rows) 10 



Color 5 



Total 100 



EXERCISE 19 



Statistical Study of Ears of Corn 



This should accompany or follow Exercise 18. 



Object. (a) To study critically and statistically the various 

 parts of ears of corn. (6) To work up these data by biometrical 

 methods, drawing curves, and ascertaining mean, standard 

 deviation, coefficient of variability, etc., for the various parts 

 of the ear. (c) To illustrate testing for germination. 



Materials. Each student should be given the same ears of 

 corn which he had for Exercise 18 ; tapes, scales, etc. 



The following form should be filled in by each student : 



NOTE. This should not be merely a mechanical process, but 

 the student should give each step very careful thought. These 

 tables are given to assist in organizing the student's method and 

 his thinking, but not to replace them. Do not study the method 

 but the plants. Consider carefully the significance of each step. 



