EXERCISE 110 

 PLANT BREEDING 



Materials. Ears of corn from the preceding exercise. The exer- 

 cise will require a plot of ground, either at the home of a pupil or 

 in the school garden. The results of each experiment will be avail- 

 able to the class of the following year and may be made the basis of 

 the study in Exercise 109. The classes in botany and agriculture 

 may very well cooperate on this experiment. 



Directions for work. Select several of the heaviest ears from 

 those studied in the preceding exercise and several of the 

 lightest. Preserve all the data regarding these ears. Assign 

 to each ear a number or other identification mark. Use this to 

 mark the plantings in the field as well as all records. 



Plant at least a hundred grains from each ear, planting all 

 the grains from one ear in a row by themselves. If it is in- 

 tended to continue the experiment in later years, using selec- 

 tions from next year's crop for seed, the rows planted with seed 

 from the poor ears should be located at least several rods from 

 those planted with seed from the best ears. (Why ?) Alternate 

 rows should be detasseled. (Why?) 



When the crop is gathered at the end of the season, keep 

 the product of each row separate from that of the other rows. 

 Weigh and make table of distribution for each row, or for as 

 many rows as possible, similar to the table in Exercise 109. 

 Graphs may be made also. Compare the record of each row with 

 the record of the ear from which it was planted and with that 

 of the whole group of ears studied in Exercise 109. Has the 

 quality of the crop been changed by selection ? Is the progeny 

 of the best ears better than the average of the preceding year? 

 Is it as good in each case as the ear from which it sprung? 

 Are any of the ears better than those from which they sprung ? 



References 



BERGEN and CALDWELL. Practical Botany, chap, xxiii. 

 BERGEN and CALDWELL. Introduction to Botany, chap. xii. 

 DAVENPORT. Domesticated Animals and Plants, chaps, ix, xi, xii, xiii, 

 xvi. Ginn and Company. 



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