154 MAIZE 



CHAP, type with the predominating number of rows is the one most 

 suitable for propagation. 



The number of rows may either exceed or fall below that 

 of the type ; the whole gamut (from 8 to 24 or more) may be 

 found in one breed. It does not necessarily follow that an 

 1 8-row Iowa Silver-mine is not an Iowa Silver-mine, nor that 

 a 10-row Hickory is some other breed. But it is found 

 that either below or- above a certain number in any one type, 

 deterioration takes place ; in Iowa Silver-mine, for example, 

 the ears bearing 12, 18, and 20 rows respectively, prove un- 

 desirable for propagation, entirely apart from the question of 

 the number of their rows. 



ill. Effect of Diameter of Cobs. — There is a popular idea 

 that a thin cob is a highly desirable characteristic of a good 

 type of maize, and a certain amount of simple selection on this 

 basis has been carried out by South African farmers. In 

 reality increase in the amount of grain is generally accom- 

 panied by increase in the size of the cob on which it is borne, 

 not only in length but also in diameter. The writer's investi- 

 gations show that increased yield of grain, by actual weight, 

 is usually accompanied by increase in average weight of cob. 

 The longest ears, however, do not always carry the greatest 

 amount of grain. Heavy yield does not depend entirely 

 either on large ears or on thin cobs. 



Of two ears of equal circumference the one with the thin- 

 nest cob is the most desirable, because it carries more grain. 

 But a thick ear with deep grain on a thick cob is infinitely 

 more desirable than a thin ear with shallow grain on a thin cob 

 (Fig. 63). An ear of Golden King g\ inches long produced only 

 8 ozs. of grain, while an ear half an inch shorter produced 10-25 

 ozs. of grain, or 2 \ ozs. more than the long ear. This was due 

 entirely to the depth and weight of the individual grains. The 

 cob that produced the most grain was half an inch shorter than 

 the other, but it was half an inch greater in circumference, and 

 weighed | oz. more. On a half-stand of only 4,200 bearing 

 plants per acre this difference means an increase in yield of 3 

 muids per acre in favour of the thicker cob. 



112. Need for Earlier-ripening Breeds. — An important 

 point for consideration in the Transvaal and Orange Free 

 State, and in the Uplands of Natal, is early maturity. On the 



