. Bulletin of the Department of Agriculture. Agriculture; Agriculture. 10 BULLETIN 925, IT. S. DEPAETMEXT OF o 10 en Fig. 3.—Frequency distribution for the length of the third branch in an F2 of Tom Thumb pop corn X Florida teosinte. character affected is the length of the ear stalk, which shows a reduc- tion in internode length similar to that of the main culm. "While this may be considered simply as the general extension of the brachytic tendency to all the lateral branches, as indicated also by the condition of the suckers, it must be remembered that the brachytic na
. Bulletin of the Department of Agriculture. Agriculture; Agriculture. 10 BULLETIN 925, IT. S. DEPAETMEXT OF o 10 en Fig. 3.—Frequency distribution for the length of the third branch in an F2 of Tom Thumb pop corn X Florida teosinte. character affected is the length of the ear stalk, which shows a reduc- tion in internode length similar to that of the main culm. "While this may be considered simply as the general extension of the brachytic tendency to all the lateral branches, as indicated also by the condition of the suckers, it must be remembered that the brachytic nature of the ear stalk on plants of normal stature is not ordinarily reflected in the main culm. This further shortening of the ear stalk on brachytic plants indi- cates that the brachytic stalks of normal ears are the result of a genetic change separate from that which caused brachytic internodes on the main culm. Support for this latter con- tention is derived from a hy- brid between Florida teosinte and Tom Thumb pop corn (3). If the ear stalk is an example of brachysm similar to that of the main stalk, the second generation of the hybrid between teosinte and maize should give the same evidence of segregation of this character as is found with the internodes of the main culm when plants with brachytic culms are crossed with those of normal stature. With the second-generation plants, the third branch from the top on the main culm is assumed to be homologous with the ear stalk of normal maize, since it is borne at approximately the same node as the ear of maize. The frequency distribution for the length of this. branch on second-generation plants of the Tom Thumb X Florida hybrid is shown in figure 3. It is apparent that there is no bimodality in the distribution of branch lengths, and it must be concluded that the brachysm of the ear stalk of normal maize does not behave as a simple Mendelian character in crosses with teosinte. Slight evidence for the discontinuous nature of
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