18 



BREEDING DEOUGHT-KESISTANT FOEAGE PLANTS. 



power of the progeny. Column 6 of the table gives the seed yield 

 per 100 grams w^eight 6f plant, showing the relation between the seed 

 yield and forage production in each progeny row. It will be seen 

 that a large seed yield is usually associated with a large forage yield, 

 as is shown b}^ a comparison of columns 4 and 5. This result throws 

 some light upon the Cjuestion whether or not heavy seed production 

 and heavy forage production are opposed, or whether they can be 

 combined in the same individual; the results seem to indicate that 

 these two characteristics can be combined. This purpose has, in fact, 

 been constantly kept in mind in the selection of the mother plants. 



Table II is inserted to show the comparative yields of the strains 

 represented in the breeding work. It will be seen that strain E ex- 

 ceeds all others in both seed yield and forage production, as showm 

 b}^ the yield per plant, and that large seed yield and heavy forage 

 production can be combined in the same strain. 



Table II. — Proportion of plants ivinterkilled and average yield of each strain represented 

 in the alfalfa-breeding nursery at Belief ourche, S. Dak., in 1909. 



WINTERKILLING. 



The winterkilling of the varieties in the breeding nursery during 

 the winter of 1908-9 was practically negligible, while the broadcast 

 plats and cultivated rows of the same varieties did not show any 

 killing at all. The nursery method of planting, where each plant 

 stands alone and unprotected, is the most severe test of hardiness. 

 At the Ashcroft (S. Dak.) Weather Bureau station, where conditions 

 are probably most nearly representative of the Bellefourche Experi- 

 ment Farm, a temperature of — 30° F. was recorded in January, 1909. 



It should be said that the varieties of alfalfa represented in the 

 breeding plats at the Bellefourche Experiment Farm have been sub- 

 jected to severe mnterkilling tests for several generations. They 

 represent selections, some of three and some of four generations of 

 individual plants grown in the breeding nursery at Highmore under 

 conditions which eliminated the less hardy individuals. The mini- 

 mum temperatures recorded during the time the w^ork w^as carried 

 on at the Highmore substation are as follows: 1904, —27° F.; 1905, 

 -36° F.; 1906, -31° F.; 1907, -27° F. There was some winter- 



196 



