April I, 1920 



A Teosinte-Maize Hybrid 



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TASSEL GROUP 



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PRIMARY BRANCHES 



Primary tassel branches are much more numerous in teoslnte than in 

 any but the very largest varieties of maize. In the Tom Thumb variety 

 the maximum number observed was 9, and this 

 falls far below the number in any normal 

 teosinte plant. The mean number for Tom 

 Thumb and Florida teosinte grown under 

 similar conditions was 4.6 and 12.5, respectively. 

 In the Fi plants the number ranged from 16 to 

 20. In the second generation the mean was 16.7 

 with a range from 5 to 29. The distribution 

 (fig. 10) was symmetrical and unimodal. 



There are two significant independent co- 

 herences, one wath characters of the height group 

 and the other with days to pollen. There are also 

 two disherences, one with number of single 

 female alicoles, the other with length of internode 

 on third. The apparent disherence with sucker 

 index is probably associated with the nega- 

 tive correlation of sucker index with the other 

 height characters. 



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SECONDARY BRANCHES 



Teosinte has a much larger number of second- 

 ary tassel branches than maize. The specific 

 may overlap, but the Tom Thumb variety 



Fig. 10. — Primary branches: fre- 

 quency distribution of plants 

 in F2. Class value, two 

 branches. 



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ranges of the parents 

 seldom develops sec- 

 ondary branches, while in Florida 

 teosinte the mean number was 

 10.3. 



In the F2 hybrid plants the mean 

 was 12.6, with a range from o to 

 46. The distribution (fig. 11) is 

 very skew, the mode being near 8, 

 but there is little evidence of more 

 than one mode. 



This character shows more 

 evidence of coherence than does 

 the character primary branches. 

 It is closely correlated with three 

 of the measurements of height. 

 There is the same negative correlation with sucker index; and 

 in addition the positive correlation with nodes without branches, 

 which Is in the direction of a disherence, is here above 0.25. 



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Fig. II. — Secondary branches: frequency distri- 

 bution of plantsin F2. Class value, two branches 



