English Sq. hd. Leutewitzer Sq. hd. English Sq. hd. 



Extra Sq. hd. I x Grenadier II 



Tystofte Smaahvede x Extra Square head II 

 (Danish) | 



"Fylgia." (0860) 



The following table shows the improvement made in 

 the wheat crop at Svalof in a comparatively short time, the 

 values being given as percentages of the yield of Native 

 Swedish wheat: — 



Pansar (Kotte x Grenadier II) 140 



Fylgia (Smaahvede x Extra squarehead II) 135 



Tystofte Smaahvede 131 



Sol 131 



Extra-squarehead II (Extra squarehead I x Grenadier 



II) 129 



Kotte 128 



Grenadier 121 



Tystofte Standhvede 121 



Criewemer 104 121 



Vilhelmina 115 



Extra-squarehead I : 112 



Native Swedish (Sammet) 100 



English Squarehead 99 



Four or more pairs of factors are undoubtedly concern- 

 ed in the yield averages of the Swedish wheats. Nilsson- 

 Ehle mentions the following: resistance and non-resistance 

 to rust (R, r). to winter (W,w), to lodging (L, l),and tillering 

 and non-tillering (T, t). It is evident that those wheats 

 that combine the greatest number of good factors such as 

 R.W.L.T. will yield highest, and those that have the most 

 poor factors such as r.w.l.t. will yield lowest. The plan 

 adopted was to select and cross varieties with the highest 

 yield and to select for a number of years the best for pro- 

 pagation. Thus higher and higher yielding varieties were 

 obtained as higher and higher yielding parents were 

 crossed. 



Breeding Varieties of Plants that are Disease- 

 Resistant 



With the great advances in methods of plant-breeding 

 in recent years the problem of breeding plants resistant to 

 disease has appealed to many workers The investigations 



159 



