22 



CIRCULAR NO. 120, BUREAU OF PLANT INDUSTRY. 



in the first or .\eiiia generation and to segregate as a monohybrid in 

 the following generation. Since both sweet and waxy endosperms 

 are recessive to horny, it became of intei'est to know what n hybrid 

 between sweet aiul waxy wonld produce. Six such crosses were 

 made in the season of 1011. In cvei'v instance tlie I'esultine: ears 

 were all horny, the endosj^ci'm in every way reseml)ling the horny 

 endosperm of ordinary varieties. 



This synthetic production of horny endos])erm from nonhorny 

 varieties at once suggests the idea that both sweet and waxy endo- 



Oa Ox s/\ 



sx 



5X 



a 



X 



BX 



SX 



5 



SX 



mm 



JC 



sx 



/3 



5X 



sx 



Sx 



5 



XLT 



'X 



/o 



X 



Sx 



mm 



1^ 



Sx 



sx 



SX 



aX 



5; 



aX 



Hom 



II 



X 



sX 



15 



.X 



sx 



SX 



sx 



mm 



s 



sx 



ta. 



X 



sx 



mxY 



/<5 



SX 



SX 



p 



4H0m 



ELHOm 



a 5wdT 



^ Hom 



I Hom 



I dWEET 



I mxY 



TOTAL 



'9 HOffNY 

 3 3tVE£T 



/ r 



Fk;. 1. — DiaKiMiii '^Imwint;- the cfiniotip romposition of scconil ^'pnerntion liylirids lietwepii 



waxy and swict varidii's of iiiaizr. 



sperms represent an imperfect development through the loss or fail- 

 ure of some element oi- hereditarv factor and that what is lackine 

 in the sweet is supplied l)y the waxy, and vice versa. Tt has often 

 been suggested that sweet endosperm resulted from a failure of com- 

 plete development of horny endosperm, but no suggestion has been 

 made regarding the nature of the deficiency. Tt now appears tliat 

 what is lacking in a sweet xariety is supplied by the waxy, and, con- 

 [Clr. 120] 



