INFLUENCE OF SIZE OE WEIGHT OF SEED KERNEL. 



33 



The average difference in 3'ieid at tlie end of three years between large grains (607 per 

 ounce), commercial sample (689 per ounce.), and small grains (882 per ounce), with Med- 

 iterranean wheat, was 2.06 bushels in favor of large grains as compared with the commercial 

 sample, and 5.18 bushels in favor of large grains over small grains. The difference in yield 

 between the large grains and the commercial sample chiefly occurred the first year; but it 

 is possible, though hardly probable, that the difference was partly due to variation in the 

 soil. The experiment has been carried on in different parts of the field for the last two 

 years, and the difference in yield is now only 0.32 Ijushel per acre in favor of the large grains. 



Cobb" reports tests of various grades of wheat kernels with respect 

 to size, and conckides that large kernels give better yields of grain. 

 The seed of one year was not the product of the corresponding grade 

 of the previous one. 



Grenfell'^ selected plump and shriveled kernels from the same bulk 

 of grain. Of these 150 kernels were sown in each row, with rows of 

 plump and shriveled kernels alternating. The germination in both 

 ro\vs appeared much alike, but the plants in the rows sown from 

 plump grain soon began to gain on the others and kept ahead for the 

 remainder of the season. The tillering was better in the plump- 

 grain plants. Grenfell tabulates his results thus: 



Variety. 



Kind. 



Stein wedel Plump 



Do Shriveled. 



Purple Straw do 



Do Plump 



Do Shriveled . 



Do Plump 



Do Shriveled . 



Plump-kernel averages 



Shriveled-kern( 1 averages 



''oTptnTs'^N^^'^^'- 

 tha?g,w.i°fhe'^d- 



96.0 

 89.3 

 89.3 

 90.0 



7fi.O 

 92.0 

 98.0 



92.7 



88.5 



Average 

 Tillering >'i|ld per 



Po^^-e'-- (bush- 

 els). 



179 

 174 



153 

 200 

 140 

 161 

 155 



180 

 155 



1.24 

 1.29 

 1.14 

 1.49 

 1.16 

 1.23 

 1.34 



1.32 

 1.23 



10.9 

 9.9 

 6.1 



10 

 6.9 

 8.4 

 7.2 



9.8 

 7.5 



As bearing upon this subject some experiments conducted by 

 Riinker'' are of interest. He weighed each of the kernels of a large 

 number of heads of wheat of the Spalding Prolific and Alartin Amber 

 varieties, and found that the heaviest kernels occur in the lower half 

 of the spike. With spikes of different lengths and weights, the 

 weight of the average kernel increases with the size of the spike. 



Weights of individual kernels from the same spikes show that 

 there is a great range in this respect. One spike, of which Riinker 

 gives the weights of all the kernels, and which is given as representa- 

 tive of the average, shows kernels varying in weight from 36 to 71 

 milligrams. 



« Agricultural Gazette of New South Wales, 14 (1903), No. 2, pp. 14.5-169. 

 ''Agricultural Gazette of New South Wales, 12 (1901 ), No. 9, pp. 1053-1062. 

 c Jour. f. Landw., 38 (1890), p. 309. 



27889— No. 78—05 3 



