576 



SCIENCE 



[N. S. Vol. XXXIV. No. 878 



total nitrogen in eggs after first cleavage with 

 that at the early blastula stage. Considerable 

 material has been collected for further work 

 along this line. L. F. Shackell 



Beaufoet, N. C, 

 September 9, 1911 



OBSERVATIONS ON THE INHERITANCE OF CHAR- 

 ACTERS IN ZEA MAYS LINN.' 



In " Red Cuzco " and some other breeds 

 of red maize, the red coloring matter is con- 

 fined to the pericarp; being therefore a fruit 

 character and not a seed character, it does 

 not appear in the ear immediately resulting 

 from a direct cross between a white female 

 and a red male. 



In a red dent breed under investigation, 

 the red pigment occurs in the aleurone layer, 

 and not in the pericarp. Being a seed-char- 

 acter, it is transmitted directly by the pollen 

 grain to the ovule of a white breed. It be- 

 haves as a dominant to whiteness; where it 

 meets yellowness in the same grain, it is more 

 conspicuous than yellow. The writer has not 

 met with a previous record of the occurrence 

 of a red pigment of this character in the 

 aleurone layer of the maize grain. 



When this red dent is crossed with a white 

 sugar breed the segregation, in the second gen- 

 eration, of the two pairs of characters redness 

 vs. whiteness and starchiness vs. sugariness, 

 is in approximately the following propor- 

 tions : 



- ^ , f starchy 56.25 1 __ , 



Eed \ ■' ^ = 75^ 



( sugary 18.75 j 



Whitel^*"'^^^ '«'p11 = 25^ 



(^ sugary b.Zo J 



In other words: 



Red Grains 



Starchy grains 75;ii of 75^ = 56.253; 



Sugary grains 25i of 75^ = 18.75;< 



75.00)i 



White Grains 



Starchy grains 75^ of 25^ = 18.75^ 



Sugary grains 25^ of 25;^ = 6.25;^ 



25.W 



^ Fuller details will shortly appear in the Trans- 

 actions of the Boyal Society of South Africa. 



A single grain has been found on the ear 

 studied, which distinctly shows the starchy 

 character in one half and the sugar character 

 in the other, a very unusual feature. 



A study of row-numbers in maize-ears 

 indicates that within certain limits the num- 

 ber of rows of grain on an ear is subject to 

 fluctuating variation, which may perhaps be 

 affected by season or food supply, or both. 

 In more than thirty plants of Arcadia sugar- 

 maize studied this year, each of which pro- 

 duced two ears on one stalk, the uppermost 

 ear has had a different number of rows from 

 that of the lower ear. On thirteen plants the 

 largest number of rows occurred on the lower 

 ear, while on eight plants the largest number 

 was on the upper ear. In twelve plants of 

 two ears the row-numbers were the same on 

 both; in one case there were four more rows 

 on one ear than on the other. Several plants 

 of Hickory King, bearing two ears, have also 

 produced different numbers of rows on the 

 two ears. 



The range of variation appears to be lim- 

 ited, however. A normally 8-rowed type 

 ranges between 4 and 14 rows, while a nor- 

 mally 18-rowed type ranges between 12 and 

 24 rows. 



The result of crossing an 8-row with an 

 18-row type of maize is to produce an inter- 

 mediate type in the first generation, both 8- 

 row and 18-row types practically disappear in 

 the heterozygous form. The intermediate- 

 type bears mostly 10, 12 or 14 rows, the 12- 

 row type greatly predominating. The ex- 

 periment will be continued next year, to de- 

 termine the proportion of the 8-row and 18- 

 row types which reappear. The ears pro- 

 duced by the cross and the reciprocal cross 

 are indistinguishable. 



A white-cobbed breed crossed with a red- 

 cobbed produces a red cob in the first filial 

 generation, and so does the reciprocal cross. 



J. BuRTT Davy 



Department of Agriculture, 

 Pretoria 



