62 GRASSES OF IOWA. 



Walter T. Swingle and Herbert J. Webber, in a paper on 

 Hybrids and their utilization in Plant Breeding, say as follows*: 



The most convincing series of experiments was carried out 

 by the famous French plant breeder, Henry L. de Vilmorin, in 

 1866. In the spring of that year he planted a dozen varieties 

 of maize from 1,000 to 1,300 feet apart, which distance was 

 found sufficient to prevent spontaneous inter-crossing by wind- 

 blown pollen. The ears to be crossed were enveloped in thin 

 flannel, which excluded pollen perfectly, for such ears, if not 

 artificially pollinated, never gave a single kernel. To have a 

 standard for comparison, an inclosed ear of each sort was arti- 

 ficially pollinated from the same sort. The ears thus obtained 

 were imperfectly filled, but the kernels reproduced all the 

 characters of the seed planted. On the other hand, when 

 inclosed ears were artificially crossed ' with pollen from 

 another sort, * * * the ears often, but not always, 

 contained kernels showing the characteristics of their male 

 parejt. The proportion of such grains, when they existed, 

 was very inconstant, being liable to vary from 1 to 60 per 

 cent. ' The efl'ect was limited to changes in the color of the 

 kernels. In most cases the pollen of a black corn was used in 

 crossing, and this color exis':s in the substance of the kernel 

 No cor elusions were drawn except from plats of maize, the 

 e irs of which, when left exposed or fertilized with their own 

 pollen, reproduced without change the sort planted. 



"In 1867 Hildebrand reported an experiment in crossing 

 corn, using a yellow sort for the female and a dark brown sort 

 for the male. Realizing that the older experiments had been 

 faulty, since no proof was given that the sort used as the 

 female parent was pure and might not be showing the effects 

 of a previous cross, he pollinated some of the plants of the 

 yellow sort with their own pollen and obtained ears, all the 

 kernels of which were exactly like the mother grains. On the 

 other hand, two eirs obtained by fertilizing the yellow sort 

 with pollen of the dark brown sort had about half of the ker- 

 nels like those of the mother sort, or a little lighter, while the 

 other half, scattered about among them, were a dirty violet 

 col jr. On these latter, therefore, the pollen of the brown-ker- 

 neled sort had exercised a direct transforming influence. " 



Numerous other experiments have been made in this coun« 

 try on the subject of the immediate influence of foreign pollen 



♦year book U. S. Dept. of Agr. 1897: 404-405. 



