HERITABLE CHARACTERS OF MAIZE 



VII. MALE STERILE' 



Lewis A. Eyster 

 College oj Agriculture, Cornell University, Ithaca, New York 



IN SOME earlier experiments with 

 maize Dr. R. A. Emerson observed 

 that some of his plants failed to 

 produce pollen. Later, it was recog- 

 nized that these plants were occurring 

 in proportions approximating 25 per- 

 cent in progenies from two closely 

 related self-pollinated ears. Crosses 

 and backcrosses have shown this male 

 sterility, designated by the fiictor sym- 

 bol ms, to behave as a simple Mendel- 

 ian recessive to normal. Tables I and II 

 give the numbers obtained in a few 

 cultures. 



DESCRIPTION OF STERILE PLANTS 



Male sterile plants are distinguish- 

 able from the normals only in the 

 tassel and anthers. No pollen forms in 

 the anther sacs and they remain unde- 

 veloped. Figure 21 shows the relative 

 sizes of anthers of normal and of male 

 sterile plants. The sterile spikelets 

 are almost empty and usually remain 

 flattened against the rachis, giving a 

 characteristic appearance to the whole 

 tassel. This appearance is shown by 

 the male sterile tassel in Figure 22 

 as contrasted with the normal tassel in 



HOW STERILE MAIZE ANTHERS COMPARE WITH NORMAL ONES 



The photOKHiph shows sonic spikflcts and in(li\iihial antluTs from normal maize tassels at the 

 top in comparison with the spikelets and anthers from male sterile tassels below. The latter are 

 almost emi)ty; no jKjllen forms in the anther sacs and they remain imdeveloped. (Fig. 21.) 



'Paper No. 91, Department of Plant lireeding, Cornell Inivcrsity, Ithaca, New York. 



i3« 



