EXERCISE XXII. 

 ADAPTATION OF CORN. 



Supplies for a Laboratory Section of Twelve. To avoid unnecessary complications the varieties chosen for 

 this exercise are all white. Aside from color the varieties named in each group were chosen quite at random, but 

 are typical of the corn grown in the sections from which they came. 



For this exercise there are needed six ears from at least one variety from each of the following groups : 



"Northwest" (here considered to be the Dakotas and northwest Minnesota). Payne's White Dent, Pioneer 

 White Dent, Disco 85 Day Corn. 

 Southern Illinois and Indiana. 



Johnson County White, Horse Tooth, Boone County White, Silver Mine. 

 Western Nebraska. 



Marten's White Dent or other local varieties. 

 Central Nebraska. 



Beckhoff's White Dent, Chaloud's White Dent, St. Joseph White, locally grown Silver Mine. 



Nebraska White Prize, Chase's White Dent, locally grown Silver Mine. 



INTRODUCTION. Adaptation in corn is a suitable relationship between the corn plant 

 and the environment in which the corn exists. Corn is said to be adapted to a given locality 

 when it produces as good yields of sound corn from year to year as may be expected under 

 the conditions which is must meet. Chief among these conditions are rainfall, length of 

 growing season, and kind of soil. 



1. Compare a representative type of corn from the "Northwest" (Payne's White Dent, 

 Pioneer White Dent or Disco Eighty-five Day Corn) with a representative type from the 

 southeastern section of the corn belt (Johnson County White, Horse Tooth, Boone County 

 White, or Silver Mine) as to (a) size of ears; (b) depth of kernels; (c) indentation. 



2. (a) Compare the rainfall of the "Northwest" with that of southern Illinois and In- 

 diana. Fig. 18, page 45. (b) Compare the length of growing season. See Fig. 48, p. 72. (c) 

 Which section is most subject to great extremes of wind, heat, and drouth? 



3. Compare a type of corn which has been developed and long grown in western Nebraska 

 with a type long grown in the eastern part of the state. (As examples of typical western Nebraska 

 corn, one may use Marten's White Dent, or other local white varieties. Good examples of 

 eastern Nebraska corn may be found in Nebraska White Prize, Chase's White Dent, and lo- 

 cally grown Silver Mine.) 



How do corns from east and west Nebraska differ as to (a) Size of ear; (b) depth of 

 kernel; (c) indentation? 



4. Now compare with the two extremes, samples of corn developed and long grown in 

 central Nebraska. (Good examples of central Nebraska corn are Beckhoff's White Dent, 

 Chaloud's White Dent, St. Joseph White, and locally grown Silver Mine.) How does central 

 Nebraska corn compare with corn developed'to the east and to the west of it? 



5. (a) After a study of Figs. 20, 21 and 49, pages 47, 48 and 73, answer the following ques- 

 tions: How does western Nebraska compare with eastern Nebraska in rainfall? Altitude? 

 Length of growing season? (b) Reasoning from the above facts and from what you have 

 heard of the western parts of the "States of the Plains," are conditions there favorable or un- 

 favorable to maximum crop production. 



6. (a) Basing your reasons upon what you have learned from a study of Nebiaska con- 

 ditions and the effect of these conditions upon corn, account for the differences you have 

 observed between corn raised in the "Northwest" and that raised in southern Illinois and 

 Indiana, (b) Where, with relation to the corn belt, would it be necessary to travel but a 

 short distance (200-400 miles) in order to encounter great changes in the character of corn? 



70 



