52 



JOURNAL OF TTTK KO^ AIj llOUTTCULTr RAIi SOOl l-VrY. 



\Yhen carefully isolated, ilii-ow;^ annnall)^ varying perceniiagos of 

 "rogues." The annual elimiuniion of iliese "rogues" may or may 

 not, according to chance, purify the strain in course of time. 



The adoption of tlie IMendelian system of founding a true stock on 

 a single individual may appear to be a simple matter, but in reality 

 it is somewhat difficult to carry out in practice on a large scale, and 

 extensive operations require a good deal of careful organization to be 

 truly effective. In order to ensure the final selection of a single true 

 breeding individual, many single individuals have to be selected. Each 

 one of these must be so disposed, that during the flowering season all 

 are strictly isolated not only from one another but from anything else 

 of a similar nature. The seeds of each individual must be separately 

 harvested, stored, and tested in the trial grounds, and so on. 



But once the true-breeding individual is found, its stock and seed 

 will, with strict isolation, be permanently established, without any 

 further selection or " rogueing," and can be increased annually to any 

 extent. 



It is obvious that apart altogether from the question of the recog- 

 nition of the advantages of the Mendelian system of breeding, there 

 are certain practical difficulties that have to be faced. In any ex- 

 tensive operations the initial expenses of carrying out the Mendelian 

 system of breeding are bound tO' be heavy, and early returns are not 

 to be expected. Later returns, however, should fully compensate the 

 grower. 



Old methods of cultivation die hard, and in the circumstances, it is 

 not surprising that professional seed growers generally have hesitated 

 to adopt the new methods, even in the few cases where they clearly 

 recognize the great advantages of the Mendelian system. Once a 

 beginning has been made, however, there will be no looking back, for 

 there is no doubt that the Mendelian system of breeding has come to 

 stay. 



Mendelism stands or falls by the purity of its cultures. No other 

 method of plant-breeding is known which can guarantee 100 per cent, 

 of purity in its cultures. When buyers once realize that such a 

 cherished dream is practicable there will be no more "rogues," and 

 Mendelian seeds will be the only profitable seeds to grow. 



