186 



THE SMALL GRAINS 



seed separated into the following grades indicating the 

 diameter of the kernels : 3.25 mm., 3.00 mm., 2.75 mm., 

 2.50 mm., 2.25 mm., 2.00 mm., and tailings. In the third 

 and fourth trials only four grades were used : very large, 

 3.25 mm. ; large, 3.00 mm. ; medium and small, all re- 

 maining sizes. The most common size of kernel in ordi- 

 nary seed wheat was found to come nearest to 2.50 mm. 

 in diameter. It was concluded that Australian wheat 

 could and should be improved to the stage of at least an 

 average diameter of 3.00 mm. In addition to the better 

 yields resulting generally from the large seed in these 

 experiments, there was better germination of such seed, 

 and the plants from large seed were more vigorous and 

 their grain of better quality. It was found that the 

 superior yield from large plump seed was always suffi- 

 ciently pronounced to justify the cost of first-class clean- 

 ing of ordinary wheat for seed to the extent of 10 per cent 

 of the value of the yield to the acre, without loss to the 

 grower. 



185. Many factors influencing seed tests. In con- 

 nection with Cobb's experiments a calculation was made 

 of the number of kernels contained in equal weights and 

 equal volumes of seed. The interesting results are here 

 tabulated : 



TABLE II. A. NUMBER OF KERNELS IN EQUAL WEIGHTS OF DIF- 

 FERENT GRADES OF PURPLE STRAW WHEAT 



