LESSONS OF POTATOES FOR EUEAL SCHOOLS. 5 



be mounted and kept for class use. Obtain potato " balls," if 

 possible. 



Class exercise. — The first step in the selection of seed potatoes is 

 the inspection of the field while the plants are yet green and vigor- 

 ous. Wliy? Select and mark plants which are true to type, free 

 from disease, stocky, and vigorous. The typical plants of the varie- 

 ties grown in the district may be brought to class and their char- 

 acteristics studied. Why is a vigorous top growth essential? 



At the time of harvesting, select superior tubers from the best hills 

 in the areas previously worked. Choose productive hills which have 

 a good number of fairly large tubers and very few culls. If the 

 grower is interested in selecting and breeding a superior strain, it 

 may be desirable to keep separate the product of several especially 

 good hills. All tubers selected should be normal in size, shape, and 

 color, and free from scab and other signs of disease. Somewhat 

 immature tubers make better seed. 



What varieties, early and late, are most common in this district? 

 Which have only a local reputation ? Which market readily ? Why 

 is it not as well to plant the seed from the " seed ball " as to use the 

 tubers? Why not make the selection from the bin in the spring? 



Practical exercises. — Have each pupil practice identifying in the 

 classroom the varieties of potatoes to be found in the district. If 

 any have peculiar local names, try to classify them. (See Depart- 

 ment Bulletin No. 176.) Have each variety examined to observe: 

 (1) Plants — size, branching, stockiness, color, and freedom from dis- 

 ease. (2) Leaves — size, color, and peculiarities. (3) Color of the 

 flowers. (4) In the spring the shape and color of the sprouts are 

 important. (5) Tubers — shape, normal size, color, and markings of 

 the skin, number and depth of eyes, color and condition of flesh. 



Arrange for a field trip during which the class shall examine some 

 good potato fields and select the sections of the field from which the 

 seed should be taken, giving reasons for the choice. If the owner is 

 willing, have a few hills dug and the plant and tubers discussed. 

 Show that the tuber is a stem and not a root. Note any peculiarity 

 of any variety as adapted to certain soil or climatic conditions. Have 

 pupils apply this lesson in their own home project. 



Correlations. — Have the pupils collect and compile the district 

 survey of the potato crop as suggested by the form given below. This 

 will provide ample correlations in arithmetic, language, and spell- 

 ing. Dictate a list of questions to the class and divide the farms of 

 the district among them so that all may be reported on soon. In- 

 clude also, questions as to methods, prices, shipping rates, weights, 

 capacity and kinds of packages, disposal of culls, and other data. 

 Some of the information can not be given before harvesting. 



