1922.] 



International Potato Conference. 



909 



2.6 tons. The yields obtained in hot countries, like India, 

 have not been ascertained, but they are understood to be small. 



Those engaged in the potato growing industry in these 

 countries are convinced that, under certain conditions, it is 

 possible to lift crops of double and sometimes treble the weight 

 of the average yield, and there is a great work to be done in 

 every country in order to discover the factors limiting the size 

 of the crops, and the means whereby these factors can be 

 w^holly or partially removed. In most instances it has been 

 discovered that improved yields could be obtained by the use 

 of improved strains of seed, and by the control of certain 

 diseases to which the potato crop appears to be particularly 

 susceptible. 



Thus it was natural that the Delegates in Conference at the 

 International Potato Conference held at the Eoyal Horti- 

 cultural Society's Hall, Westminster from 16th-18th November, 

 should more or less confine their discussions to these 

 most important aspects of the matter. Mr. Wm. Stuart 

 (U.S.A.^, Mr. F. J. Chittenden (England^, and Mr. Wm. 

 Robb (Scotland), in their papers, showed that by selecting 

 tubers from robust, vigorous plants it was possible to eliminate 

 weak plants, and to build up strains superior to the unselected. 

 There was agreement, how^ever, that yield was not increased 

 to the same extent as by using for seed tubers derived from 

 crops grown in colder regions suitably supplied with a plentiful 

 rainfall. The importance of this is now recognised generally, 

 and just as England has chosen Scotland and northern Ireland 

 as districts from which to obtain seed, so other countries are 

 trying to discover suitable areas for producing their seed tubers. 

 Thus, India obtains seed potatoes from Italy, Egypt from 

 Spain, Bermuda from certain Canadian areas, and the growers 

 in South America from selected fields in the north. 



The home produced potato, therefore, does not appear to 

 have retained its full powers of reproducing a crop, a discovery 

 which had led to the popular belief that potatoes degenerate 

 when continuously reproduced by asexual processes, i.e., from 

 tubers. Dr. Salaman (England) explained that this was not 

 the true explanation, that continuous asexual reproduction had 

 nothing to do with degeneration, and also that it was impossible 

 to attribute the degeneration, if it existed, to general senile 

 decay of the potato. He suggested that the loss of vigour was 

 attributable to deterioration of the stock brought about by 

 pathological diseases, and cited " Mosaic disease " as one of 

 the causes. 



