50 



Potatoes Immune from Wart Disease. [april, 



by A. H. Bowden, who used the same methods as were 

 adopted by Misses M. D. Glynne and V. G. Jackson in 191 8 ; 

 the results are, therefore, strictly comparable. The summarised 

 results are shown in the following table : — ■ 





1 917 Crop : Non-immune Varieties. 



1 91 9 Crop : 

 Immune 

 Varieties, 



Glamorgan. 



Mean of all analyses. 



Rothamsted analyses. 



All 

 results. 



W. country 

 only.* 



All 

 results. 



W. country 

 only. 



Dry matter 



Range of variation . . 



Nitrogen in dry matter . . 

 Range of variation 



Nitrogen in fresh material 

 Range of variation 



Weight of 1 tuber, Grams 

 Range of variation 



Per cent. 

 22*09 

 17-60 to 29-08 



1-48 



.327 

 •204 to -526 



Per cent. 

 21-99 



•337 



7" 



Per cent. 

 22 -41 

 i8'33to26«33 



i« 3 8 

 •936 to 1 '84 



0-308 

 '204 to '420 



139 



39-25 to 203 -9 



Per cent. 



21 -22 



i8-69to24-76 



1-40 



1-05 to i-86 



0-305 

 0-204 to 0-420 



133 

 39-3 to 188 



Per cent. 

 23'93 

 22 -ii to 27-32 



1-65 

 1-38 to 1-98 



0-390 



o-3i5too-457 



152 

 no to 202 



* The four common varieties. 



It is impossible to make a strict comparison between the 

 immune and the non-immune varieties, because they were not 

 grown in the same season. The years 191 7 and 191 9 differed 

 in character, and the effect of seasonal differences is well-known 

 and marked. In particular 191 9, during the growing period 

 of the potato, was drier and less favourable to growth than 

 1 91 7, which would tend to increase the dry matter of the tubers. 

 A general comparison only is possible, and this indicates that 

 the percentage of dry matter and of nitrogen in varieties 

 immune from wart disease is at least as high as in ordinary 

 non-immune varieties, and, therefore, the consuming public 

 will suffer nothing by the substitution of these new varieties 

 for the old ones. 



The data are too few in number to allow of any detailed 

 comparison between the different varieties of immune potatoes. 

 It will be observed (Table on p. 51) that the sample of Leinster 

 Wonder stands out well with 27*3 per cent, of dry matter, 

 while the Improved Ashleaf had 22*1 per cent. only. The 

 percentage of nitrogen varies in the different samples, being 

 0*457 m tne sample of Witch Hill, but 0-315 only in Lochar. 

 These figures are chiefly of value as showing the existence 

 of the variations : it would need many more determinations 

 before one could say with certainty whether one variety was 

 distinctly better than another in dry matter or nitrogen 

 content. 



