10 CIRCULAR NO. 124, BUREAU OF PLANT INDUSTRY. 



The hybrid and i)Uie seeds from each of the ears, when weighed 

 separately, exhibited such striking differences that it is thought advis- 

 able to place the results on record. In every instance the hybrid 

 seed was larger than the pure seed borne on the same ear, the mcrease 

 ranguig from 3 to 21 ])er cent. 



LIST OF VARIETIES CROSSED. 



The experiments involved the foUowmg varieties: 



Missouri Col Pipe, or Collier. — The well-known, large-cobbed vari- 

 ety used in the manufacture of corn-cob pipes. The seeds are white. 

 In our specmiens the average weight per 1,000 seeds is 310 grams. 



Gracillima. — A variety of pop corn isolated from a variegated vari- 

 ety, the seed of which was originally secured from Germany. The 

 seeds are white. The average weight per 1 ,000 seeds is 67 grams. 



Variegated. — Similar to the preceding. Isolated from a podded 

 variety. The white seeds of this strain average 141 grams per 1,000 

 seeds. 



Hickory King. — A large, thin-seeded, white dent variety. The 

 seeds of the strain used in these experiments averaged 480 grams per 

 1,000. 



Mexico Blaclc. — A Mexican variety with slightly dented ''shoe-peg" 

 seeds and an intensely black aleurone. The original seed of this 

 variety consisted of one ear secured from the Valley of Mexico, Seed 

 and Plant Introduction No. 27074. The seeds of this ear averaged 

 295 grams per 1,000. As growni in our experiments the seeds are 

 smaller, averagmg only 231 grams per 1,000. 



Algeria. — A variety of pop com with beaked seeds and purple 

 aleurone. The average weight of the seeds is 125 grams per 1,000. 



DESCRIPTION OF THE EXPERIMENTS. 



It wUl be seen that the varieties involved comprise four with white 

 seeds and two with colored seeds. The color in these seeds is located 

 in the aleurone cells, the outer layer of the endospenn. Previous 

 experiments have established the fact that when pollen from one of 

 these black-seeded varieties is used to pollmate an ear of the white 

 varieties the resulting seed is colored. 



In the experiments to be described, the silks of the white-seeded 

 varieties were dusted with a mixture of pollen from the same white 

 variety and pollen of a different variety with colored seeds. The 

 ears that result from an operation of this kind have white kernels 

 that represent pure seed of the variety and colored seeds that are 

 hybrids between the white and colored varieties. In some uistances 

 the ])ollen of the white variety contributed to the mixture was taken 



[Cir. 124] 



