PLANT AND ANIMAL IMPROVEMENT 223 



ing from these seeds are less vigorous and are thereby 

 greatly handicapped at the start. The plants at first are 

 smaller and have a less healthy color than plants of ordi- 

 nary varieties, and although they usually overcome this 

 handicap, they may not always do so if the conditions in 

 the earlier part of the season are particularly unfavorable. 

 A method which overcomes these objections is now 

 being tested at the Connecticut Agricultural Experiment 

 Station, and promises excellent results. This method is 

 as follows : Four inbred strains are selected which when 

 tested by crossing in all the six different combinations 

 give an increased yield. Two of these strains are crossed 

 to make one first generation hybrid and the other two are 

 crossed to give another. These two different crosses, 

 which are large vigorous plants, are again crossed and the 

 seed obtained used for general field planting. This pro- 

 cedure may be diagrammed as follows: 



Original variety 



Inbred strains 



First generation crosses 



(AXB) 



(CXI)) 



Double first generation cross 



{AXB)XiCXD) 



In this way large yields of well-developed seed are 

 obtained, and the young plants are not handicapped in any 

 way. The beautiful uniformity of the first cross is sacri- 



