234 MAIZE 



CHAP, planted in an isolated breeding plot and each resulting plant 

 v ' should be carefully selfed. By this means it will be possible 

 to detect the results of accidental crossing with stray pollen, 

 and to prevent its spread to the other plants of the cross. 



The ears produced by these plants will show segregation 

 in the seed, if the characters involved in the cross are seed 

 characters, and from them selection of the desired grains can 

 be made. 



191. The F 2 Plants.— The ¥., plants must also be grown 

 by themselves, and selfed. If the desired character is recessive, 

 it will be possible to isolate it and commence propagation. 

 But as our knowledge of the individual unit-characters is at 

 present imperfect, it is desirable to grow the plants on for 

 another generation, and self them, in order to eliminate any 

 undesirable character which may not have appeared. If the 

 F a generation breeds true, the new type may be considered 

 fixed and we may proceed to propagate. 



192. Improvement by Breeding is Slow at First. — At best, 

 improvement by breeding is a tedious process, and the man 

 who is not prepared to be patient, methodical, and persistent, 

 should not undertake it. The writer has known men who 

 started out well, with no little expenditure of time and money, 

 but who, seeing no visible results, gave it up in disgust after 

 the first year. As has been said, visible results cannot be ob- 

 tained during the first few seasons. It is probable that there 

 is not a pure pedigree commercial crop of maize in South 

 Africa to-day, and very few elsewhere, for maize is a remark- 

 ably heterozygous mixture. Before we can hope to make 

 definite progress, we must purify the strains we wish to im- 

 prove. Hitherto time has been largely taken up with trying 

 out breeds suited to different parts of the country. Now that 

 we have formed definite ideas on this subject, we can devote 

 our attention to their improvement by breeding. 



Addendum. — Arrangements have been made by the Agri- 

 cultural Supply Association, Limited, P.O. Box 1 148, Johannes- 

 burg, to supply pure-bred seed of heavy-yielding strains of 

 maize especially suited to the High-veld of the Transvaal and 

 Orange Free State. 



