IMPROVEMENT OF VEGETABLE VARIETIES BY SELECTION. 



213 



yielders. In one case the crossing of two medium yielders iso- 

 lated from one variety of 

 corn gave a much higher 

 yield than that obtained 

 from the field run. Sup- 

 posing that all the weak 

 strains were sifted out of 

 every commercial variety, « 

 and only the strong ones § 

 left for intercrossing, then I 

 our yields should be mate- s 

 rially improved. At the <j 

 University Farm many re- 

 strains of Hubbard squash % 

 have been isolated and un- J 

 doubtedly many, if not all, % 

 of them will yield less than I 

 the field run. On the other | 

 hand they are remarkably ° 

 uniform, and perhaps a s 

 cross between two of the | 

 highest yielding strains | 

 would give a more uniform t 



a 



and productive squash than | 

 we have at the present time. | 

 Isolation of strains is also § 

 being carried on with the -5 

 greenhouse cucumber, head § 

 lettuce and onion with the § 

 same object in view. g 



Self-fertilized plants are » 

 those plants whose flowers ? 

 are of such a nature that 3 

 they usually fertilize them- % 

 selves. Illustrations of such 3 

 plants are the bean, pea, 

 tomato and perhaps the 

 eggplant and pepper. Such 

 plants diifer from the cross- 

 fertilized ones in that they 

 do not carry along a lot of 

 weak strains by crossing. However, each variety of this class of 



