356 SCIENCE IN AFRICA 



Strains from Harland's Cambodia crosses will ultimately replace the 

 best of the U.4. derivatives. Harland's Cambodia has also shown 

 itself the best of the crosses tried at Domira Bay in Nyasaland. At 

 Serere in Uganda the original U.4. has been crossed back with the 

 local variety, and a strain has now been produced that preserves 

 the hairy leaves and productivity of U.4., but in which the lint is 

 more silky and much longer and closely resembles the style of lint 

 for which a market has been developed. Another cotton recently 

 bred in Uganda from American strains is S.G. 23/8. In many 

 areas this appears to fulfil most requirements, but it is sometimes 

 susceptible to disease. Evans (1938) has discussed the possibilities 

 of growing Asiatic (short-stapled) cottons where climatic condi- 

 tions do not favour the American (long-stapled) varieties. 



In West Africa cotton has been the subject of botanical investi- 

 gadon in Nigeria, especially at Samaru in the Northern Territories. 

 The original indigenous native cotton, although still grown in 

 many parts of the Southern Territories, is practically replaced in 

 the north by the Allen strain of Upland American. Experimental 

 breeding from this has produced greatly increased yields, but 

 strains which are fully resistant to disease, especially jassid and 

 leaf-curl, have yet to be produced. A strain known as D.31 

 appears to be the most reliable, but is inferior for spinning. 

 Farther south Ishan cotton, one of the Vitifolium groups of G. 

 barbadense, has been improved by selection and distributed; it 

 grows very tall and therefore is particularly suitable for inter- 

 planting with other crops, a type of agriculture which is common 

 in parts of Nigeria and other countries which have only a short 

 rainy season. In the south of Nigeria an introduced Sea Island 

 strain is proving satisfactory. 



With the long-stapled Egyptian cottons, notable advances have 

 been made also, especially in the Sudan; for instance, Mr. Lam- 

 bert, working at Medani, has selected the new Sakel strain 15/30, 

 which is resistant to leaf-curl, shows recovery from blackarm, and 

 on poor land in bad seasons has great resistance to climatic con- 

 ditions, yielding in some cases nearly double that of the original 

 stock. Similar progress has been made in Egypt with the new 

 Giza strains. 



On the side of agricultural management, great improvement 



