96 AGRICULTURE IN THE TROPICS [PT. II 



upon the native vegetables. Hence the obvious policy to 

 pursue is to improve these. Hitherto the usual way in which 

 this has been attempted has been to introduce other varieties 

 from abroad, but in general there is but little to choose between 

 the varieties from different tropical countries if the differences 

 in methods of cultivation and effects of soil be left out of 

 account, while varieties of tropical or subtropical vegetables 

 soon deteriorate in the hot climate, if introduced from colder 

 countries. Furthermore, it is obvious that there are very well 

 marked limits to this kind of work ; every variety from every 

 tropical country may soon be introduced into any given country, 

 and then the work must come to an end. What is wanted is 

 systematic selection and improvement, a work of time, trouble 

 and expense, but the only way in which good results can be 

 obtained, and good and suitable varieties produced. A vast 

 difference would be apparent in the quality of tropical produce 

 if careful selection of seed were attended to. The European 

 seedsman keeps up the qualities of his varieties by careful 

 selection, while the same varieties in the hands of his customers 

 deteriorate in every generation. Local races should be improved 

 by selection, by scientific crossing with imported races possessing 

 desirable characters, and by careful attention to good cultivation. 

 Even wild edible plants and fruits, so often contemned as 

 "jungle stuff," may in this way become valuable products. In 

 Ceylon, a few years ago, Mr R. H. Lock, by careful crossing with 

 the European pea, so much improved the native pea that it 

 was almost a new vegetable. 



