[Cir. 120— C] 



INHERITANCE OF WAXY ENDOSPERM IN HYBRIDS WITH 



SWEET CORN.^ 



By G. N. Collins, Botanist, and J. H. Kempton, Assistant, Office of Acclimatisa- 

 tion and Adaptation of Crop Plants and Cotton-Breeding Investigations. 



INTRODUCTION. 



As soon as European settlers in America became familiar with the 

 different varieties of maize, the obvious classification of varieties 

 based on the character of the seeds came into use. In very early 

 literature we find such terms as flint, dent, and sweet referred to as 

 representing classes already well known. The popular classification 

 was crystallized into formal descriptions by Salisbury in 1849, but 

 it was not until 1884, when Sturtevant extended the classification and 

 applied as technical names Latin equivalents of the popular names, 

 that the classification was generally recognized by scientific writers. 



With the exception of pod corn, which is known only as a curiosity, 

 these groups are all distinguished by the texture or composition of 

 the endosperm. The discovery in China of a type of maize with a 

 new form of endosperm added another member to this long-estab- 

 lished series.^ 



BEHAVIOR OF THE HYBRIDS. 



The waxy endosperm, characteristic of this Chinese variety, has 

 never been observed in any American variety, while in all of the im- 

 portations of this Chinese variety nothing but waxy seeds have been 

 observed. When crossed with varieties that have a horny endosperm 

 the waxy endosperm is completely recessive, the immediate result of 

 the cross being seeds that are indistinguishable from those of horny 

 varieties. In the second generation of crosses segregation appears to 

 be complete, and the proportion of waxy to horny seed approximates 

 the Mendelian monohybrid ratio, 1 : 3, with small, though significant, 

 deviations. Detailed results of a series of crosses between waxy and 

 horny are given in another place.^ 



In a general way waxy endosperm may be said to behave like 

 sweet endosperm, which has also been found to be recessive to horny 



1 Issued Apr. 5, 1913. 



2 Collins, G. N. A new t.vpe of Indian corn from China. U. S. Department of Agricul- 

 ture, Bureau of Plant Industry, Bulletin 161, 1909. 



3 Collins, G. N., and Kempton, J. H. Inheritance of waxy endosperm in hybrids of 

 Chinese maize. IV<" Conference Internationale de G^netique, Paris, 1911, p. 347-357, 

 1913. 



[Cir. 120] 21 



