jtg Arend. L. Hagedoorn and A. C. Hagedoorn. 



is, that possibly the effect of selection is so slow, that two or three 

 generations might not suffice to give an appreciable result. What 

 we need to know therefore, is whether, if in a practically pure line 

 extreme plants are selected for a great number of generations, say 

 twenty or more, this selection has any effect. 



It stands to reason, that direct experiments, serving to make 

 this point clear, would take far too much time. Happily, we chance 

 to have a very good example of the effect of half a century of 

 selection in pure lines. 



Louis de Vilmorin, about 1840 began a collection of commercial 

 wheats, a living museum, which has been perpetuated to this day 

 by members of his firm. He at that time already selected one single 

 plant of every variety each generation, and ultimately produced all 

 the seed sold annually by his firm from one plant some generations 

 back. This method of growing pure lines of wheat has since been 

 reinvented several times, amongst others by Nilsson in Svalöf about 

 twelve years ago. Louis de Vilmorin, at the same time as starting 

 his living museum of pure lines, made a collection of ears of his 

 wheats. This collection of ears was discovered in a unused chest of 

 drawers in an attic. They were rather well preserved, although some- 

 what yellowed by age. But, as was to be expected, the seed in 

 them, in as far as it was not destroyed by insects, failed to germ. 

 When this collection was found, M"^ A. Meunissier of Verrieres, the 

 genetician of the firm of Vilmorin Andrieux and C°, took three dozen 

 ears, representing varieties still in the collection, and which have 

 been bred during all the intervening time. He took an ear of the 

 igii harvest of each of these same 36 varieties for comparison. Some 

 of the varieties had been bred since 1842, others since I^50 or 1852, 

 all for about half a century. During all this time, they had been, 

 all of them, subjected to a rigourous selection by the wheat-experts 

 of the firm. In varieties with compact ears, the plant with the 

 compactest ears was always chosen, in such with branched ears that 

 with the best branched ear, and so on. 



Half a century of selection had not changed any one of the 36 

 varieties in the least. The 1850 ear was in every case identical to 

 the 191 1 one. It is easy to verify this statement from the photo- 

 graphs one of us took from the- ears. 



We think, that these photographs must convince even the 

 most sceptical selectionist, that genes can not be modified by any 

 selection. 



