April I, 1920 



A Teosinte-Maize Hybrid 



29 



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ESrDEPENDENT CHARACTERS 

 POSITION OF BEST SPIKE 



In maize the pistillate spike is terminal on the branch. In teosinte 

 there are usually a number of spikes of nearly equal size, the prophyllary 

 branch usually producing spikes as large as any on 

 the branch. 



In the F2 hybrid plants this character was de- 

 termined on the third branch. The nodes were 

 numbered from the base of the branch, the pro- 

 phyllary branch being recorded as o. The range 

 was from o to 9, with the mode at 3. The mean 

 was 2.22. The distribution (fig. 27) was decidedly 



skew, but there was little 

 evidence of more than one 

 mode. 



In -its relation to other 

 characters, this character 

 is very irregular. The large 

 number of disherent corre- 

 lations may indicate that 

 the terminal position of the 

 pistillate inflorescence in 

 maize is not inherited as a 

 tendency for the lateral pistillate inflorescences 

 to be located near the top of the branch. When 

 secondary ears are developed in maize they are 

 always near the base of the branch, and the 

 expression of this tendency in inheritance may 

 be the explanation of the apparently disherent 

 correlations. 



NUMBER OP AUCOLES 



The number of alicoles in a well-developed 



spike of Florida teosinte is 7. In Tom Thumb 



maize the number is seldom less than 100. The 



number recorded in a normal ear of 



maize is 50, in a Peruvian variety from the 



region of I^aike Titicaca. This is, therefore, 



one of the characters in which there is no approach to overlapping 



in the parental species. 



The Fi plants had spikes with from 11 to 18 ailicoles. 



Fig. 27. — Position of best 

 spike: frequency distribu- 

 tion of plants in Fs. Class 

 value, one node. 



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Fig. 28. — Number of alicoles: fre- 

 quency distribution of plants lowCSt 

 in F2. Class value, three ali- 

 coles. 



In the secpnd 



generation the range was from 7 to 40. The mean was 17.85 with nearly 

 symmetrical distribution (fig. 28), the mode being at 16. 



