lvi PROCEEDINGS OF THE ROYAL HORTICULTURAL SOCIETY. 



from Scotland, but the second year's crop was best. After the second 

 year, however, rapid deterioration set in. He had found that if the Scotch 

 seeds were put in thoroughly worked soil with plenty of minerals, but 

 which was deficient in nitrates, he got a good crop. He had planted 

 ' Snowdrops ' on poor soil in which nitrogen was very deficient, and they 

 had never yet fallen victims to disease. Under these conditions he had 

 obtained better crops than from potatoes grown in richer soils. That was 

 also true of the chrysanthemum, or any plant. In the case of the apple, 

 which was not forced to the extent that vegetables were, they did not get 

 deterioration of varieties. That was why the strawberry did not 

 deteriorate to the same extent as the potato. The reason was that the 

 grower realised that he must have abundance of minerals and not too 

 rich soil. In other words, he believed that abundance of nitrogenous 

 plant-food caused rapid deterioration by altering the cell-structure. 



Mr. Dean, supplementing his paper, said deterioration resulted from 

 planting small tubers. Large tubers should be planted, as that, he 

 believed, was one of the primary causes of the Scotch seed giving such 

 good results. 



Mr. Worsley added that when he said he had produced potatoes on 

 land for eight years he should have stated that he selected large tubers. 

 That was no doubt the reason why he succeeded in growing them well 

 for eight years. 



Mr. Chittenden said it was the common practice in Essex to get seed 

 from Scotland. He had been informed that it was necessary to change 

 from one district to another. It was not necessary to make a big change 

 in the climate, though that would probably follow there, he thought, from 

 the "lay" of the land. 



Scientific Committee, April 11, 1905. 

 Dr. M. T. Masters, F.R.S., in the Chair, and eleven members present. 



Deterioration of Yegetatively Reproduced Varieties. — The following 

 letters upon this subject from several gentlemen were read, mostly pointing 

 to the conclusion that varieties do deteriorate : — 



Mr. Burbidge : This is a wide question and has been discussed ever 

 since the late Thos. Andrew Knight wrote his Treatise on the Apple and 

 Pear in 1797. It was, I believe, Knight's first book, a small octavo, and 

 is now rather rare. It is a common belief amongst gardeners that 

 varieties do deteriorate or "go back " in gardens. This I myself do not 

 believe is true if they are well, wisely, and properly cultivated. De- 

 terioration is very often, even if not always, the result of bad culture, 

 senility, or neglect. It is, moreover, due in many cases to growing the 

 same variety too long on the same soil, and to the use of too much 

 manure. With potatoes this is especially the case ; but no potato as a 

 variety deteriorates on good soils if the seed or sets are changed, or 

 obtained from a different soil and climate every year. The old ' Ashleaf 

 Kidney ' potato is as old as most potatoes, and is still one of the best. 

 The craze for novelty and competition in the trade often lead to good old 

 varieties being superseded by new seedlings or selections, or by old kinds 



