1913] Shaw: Studies on Influences A fecting Protein Content of WJieat 111 



half of the normal it is quite likely that the plants do not receive 

 enough sunshine to allow even the maximum nitrogen metabolism 

 to take place. 



The fact that there is a greater difference in the percentage 

 of protein for different seasons than there is in the same season 

 under various amounts of sunshine certainly tends to show that 

 there are factors other than sunshine, which play just as im- 

 portant a part in determining the composition of the grain. 



Certain experimenters have stated that the exposure of grain 

 to the action of strong sunlight after it had become ripe had a 

 tendency not only to bleach the kernels, forming the so-called 

 "yellow berry," but also to lower the protein content. Attention 

 was called to this by Lyon and Keyser based upon some trials 

 made at the Nebraska station. On account of the fact that the 

 sunshine in the main grain-growing regions of California is very 

 intense during the ripening and harvesting period, and that the 

 grain frequently stands for several weeks on the straw in the 

 field, an attempt was made in 1906 at Yuba City to ascertain 

 if this effect held under the conditions which obtain in this state. 

 In this experiment several varieties of wheat w^ere selected in 

 which differences in the physical appearances of the grain 

 could be easily followed owing to the color of the typical and 

 changed kernels. The percentage of typical kernels in the orig- 

 inal was determined, using 5000 kernels in each case as a basis, 

 and these were seeded in plats under like conditions in the field. 

 At the maturity of the grain three fourths of the grain was cut 

 while in the hard dough stage, a few bundles being shocked and 

 left in the field, while an equal number were protected from the 

 direct action of the sunlight. The remainder of the grain was 

 left on the standing straw from July 5 to August 13, when 

 it was harvested and all three lots were threshed at the same 

 time. The experiment was repeated again in 1907. A determi- 

 nation was made of the percentage of typical kernels in each 

 lot, and of the percent of protein. The results follow : 



