WAXY ENDOSPERM IN HYBRIDS WITH SWEET CORN, 



25 



are the heaviest, followed by the waxy and sweet. A total of 3,161 

 horny seeds weighed 790.3 grams, 2,387 waxy seeds weighed 565 

 grams, and 5,247 sweet seeds weighed. 1,028.3 grams. Eedifced to 

 W' eight per seed, these results give 0.253 gram for the horny^ 0.237 

 gram for the waxy, and 0.196 gram for the sweet. The average 

 weight of the four classes, white horny, white waxy, w^hite sweet, and 

 colored sweet, was determined on 49 ears belonging to four families.^ 

 The results are shown in Table I. Since the average weight of seed 

 differs on different ears, the comparative weights of the different 

 classes are expressed in terms of the weight of the horny seeds. 



Table I. — Weight of irliite warij, colored sweet, and irhite sweet seeds of 



maize. 



There appears to be no real difference in weight betAveen the white 

 and colored sweet seeds. The sweet seeds are, however, consistently 

 lighter than the wax}^, which in turn are lighter than the horny. The 

 average difference betw^een the sweet and waxy seeds is 22.5 per cent 

 of the weight of the sweet; that between the waxy and horny is 

 5 per cent of the waxy. The volume and specific gravity of the classes 

 of seeds were also determined in eight of the ears. The results showed 

 that the differences in w^eight were associated with corresponding 

 differences in volume, the specific gravity being the same for all 

 classes. 



COMPARISON OF RESULTS WITH MENDELIAN EXPECTATION. 



In the previous pages the classes occurring in the second generation 

 of the sweet X waxy cross have been referred to as approximating a 

 9:4:3 ratio. While this approximation is so close as to exclude the 

 possibility of finding any other ratio that will more closely fit the ob- 

 served number, the deviations are too large to be ascribed to chance. 



Table II gives the number of horny, sweet, and waxy seeds com- 

 pared with the number expected in accordance with the above ratio. 

 For both the horny and waxy it will be seen that the deviation for 

 the entire series is more than five times the probable error. In the 

 case of the sweet seeds the total deviation is no greater than should 



1 The two classes, colored horny and colored waxy, could not be weighed accurately, 

 since these seeds had been clipped in order to determine whether they were horny or 

 waxy. 



[Cir. 120] 



