A Pearl aud Bartlett. 



the writer to breed true to their respective types. That is, the sweet 

 corn used never throws starchy kernels, nor does the dent ever throw 

 sweet kernels. 



In the summer of 1908 some of this dent corn was planted on 

 the sweet corn breeding plots of the Station at Farmington, Maine. 

 This planting was done in such a way that a sweet corn plot, 

 approximately an acre in extent, was bounded on two parallel sides 

 by this dent corn, there being two rows of the latter on each side of 

 the field. As fast as tassels appeared on this dent corn they were 

 removed 1), before the staminate flowers had opened and shed any 

 pollen. The detasseling was done with the greatest care, not merely 

 because of the safeguarding of the crossing experiments, but also in 

 order that none of the sweet corn, which was being pure bred for 

 another and different purpose, should be fertilized with pollen from 

 the yellow dent. As a matter of fact, only the very smallest amount 

 of pollen escaped from the yellow dent corn. From the whole acre 

 of sweet corn there were obtained only a very small number of 

 kernels (less than 25) which had been fertilized by yellow dent 

 pollen. The total number of sweet kernels produced was somewhere 

 in the millions. The amount of such pollen loose in the field was 

 negligable for present purposes. 



The ears borne on the yellow dent stalks were fertilized by pollen 

 from the sweet corn, and in consequence the kernels of these ears 

 represented the Fj seed of a cross in which the sweet corn was the Ö , 

 and the dent corn the g parent. All of these kernels were like each 

 other and like the yellow dent parent in appearance. This is in accord 

 with the well known results of Correns, Lock, East and others demon- 

 strating that in maize yellowness and "starchiness" of endosperm are 

 dominant over whiteness and "sweetness" (3). The appearance of ears 

 bearing these Fj seeds was exactly hke fig. iB. Several bushels of 

 such ears were grown in 1900. 



In 1909 Dr. Owen Smith 2) of Portland very kindly offered to 

 plant a large plot of this Fi cross-bred maize at his farm on the 

 shore of Sebago Lake. Two acres were accordingly planted with F^ 

 seed, producing Fi plants, which in turn bore Fo kernels. This 



'1 By Dr. Frank M. Surface, who carried out the main part of tlie field work 

 in corn breeding in 190S. 



-) It gives me great pleasure to express both the indebtedness and thanks 

 of the Experiment Station to Dr. Smith for his aid in this and other plant breeding 

 work carried on during the last four years. R. P. 



