1 68 Journal of Agricultural Research voi. xviii. no. 3 



SUMMARY 



(i) This investigation is a continuation of the work reported in Kansas 

 Agricultural Experiment Station Bulletin 156. 



(2) The opaque, starchy spots in wheat kernels which give them the 

 designation of yellow-berry kernels almost invariably begin to appear 

 in the neighborhood of the germ or embryo, the lower end of the kernel 

 as it stands on the plant, and spread from there upward. 



(3) One hundred and sixty-four lots of wheat were investigated to deter- 

 mine the relation of yellow-berry to field conditions, especially the period 

 between first heading and ripening. Seventy-seven of these lots were 

 pure strains or pure lines, and 87 were checks or controls. 



(4) In determining the percentage of yellow-berry, an arbitrary stand- 

 ard was adopted. If one-half or more of a kernel was opaque it was 

 weighed as a yellow-berry kernel. The flinty kernels free from opaque 

 portions were weighed separately, and the residue of the kernels were 

 designated as neutral grains. 



(5) The variation in yellow-berry percentages in the yields of the con- 

 trol rows was closely followed by that of the pure-line rows alternating 

 with them. The general trend of the whole series of the pure lines follows 

 that of the controls. 



(6) The conclusion from the field tests is that the operation of common 

 causes for the production of yellow-berry overshadowed any differences 

 that may have been due to hereditary tendencies, and precludes a definite 

 statement regarding the relation of hereditary tendencies in hard winter 

 wheats toward the production of yellow-berry. That some isolated pure 

 strains of wheat are freer from yellow-berry than others growing in the 

 same field and under apparently identical conditions of soil and climate 

 is, however, possible. 



(7) With respect to the relation of yellow-berry to date of ripening, 

 the experiment shows a higher percentage of yellow-berry with the later 

 dates of ripening. 



(8) The comparative size of the starch granules in yellow-berry and 

 in flinty grains was investigated, 500 measurements of starch grains 

 being made from hard and from yellow-berry samples of 10 strains of 

 of pure-line wheats. The largest starch grains in the yellow-berry por- 

 tions of the kernel were found to be smaller on the average than the 

 largest starch grains in the flinty portions of the same kernels. These 

 results seem to contradict those of Cobb and of Lyon and Keyser. 



(9) In respect to the average kernel-weight, the yellow-berry kernels 

 were found to weigh on the average 0.4 mg. more than the flinty kernels, 

 based on the average weight (air-dried at 100° C.) of 100 kernels. In 

 an earlier study the flinty kernels were on the average 1.4 mg. heavier. 



(10) In specific gravity the flinty kernels were found to be 0.0230 

 heavier than the yellow-berry kernels. 



