CEREALS 5 



for recital herein concerning the parts of tropical Africa 

 to which I have not referred. 



I wish now to direct your attention specially to the 

 work concerning wheat accomplished and progressing in 

 Rhodesia, British East Africa and tropical Australia, 

 where it is exotic, and in India and the Sudan, where it 

 is indigenous. 



RHODESIA. 



The distinction I have drawn -between the countries 

 where wheat is exotic and indigenous is important. 

 Empirical information, if it be derived from sufficiently 

 long experience, is valuable. A modern investigator 

 may encounter great difficulty in convincing growers of 

 indigenous plants that their methods are capable of 

 improvement, but he does at least start his work as to 

 possibilities upon a basis of results already obtained, 

 whereas the introducer of an exotic has little or nothing 

 to guide him in his operations. This was the case in 

 Rhodesia. Until quite recently no one had grown wheat 

 there. 



Starting apparently on the assumption that it was likely 

 to be a summer crop, it was grown during the rainy 

 season (October to April), but the attempts were rendered 

 unsuccessful by rust. Thus it came to be regarded as a 

 crop for the dry winter months (May to September), and 

 irrigation seemed to be essential. The next stage was 

 the discovery of the fact that considerable areas of low- 

 lying land, particularly in the granite formation, retained 

 sufficient moisture throughout the winter months for the 

 growing of winter crops without irrigation, so it is being 

 grown as a winter crop both under irrigation and as an 

 unirrigated crop on moisture-retaining soils. Even so, 

 however, the production is still far below the require- 

 ments of the country, and the Department of Agriculture 

 has, therefore, devoted much attention to the creation 

 of rust-resistant varieties which can be grown during the 

 rainy season and be rotated with maize. It is very 

 interesting to note that, although several varieties, in- 

 cluding 2vjedeah, Belaturka, and Zwaartbaard, failed 

 entirely owing to rust, some varieties were found which 



