A BRACHYTIC VARIATION IN MAIZE. 



17 



not significant. The frequency distribution for height of plant is 

 shown in figure 5. 



In yield, as measured by the total ear length, neither the normal 

 nor the brachytic F 2 plants equaled the first generation, but indi- 

 vidual plants were obtained which yielded fully as well as the best 





30 



S 7 9 II 13 IS 17 19 £1 23 2S ST 29 31 33 3S 37 39 OCM 



Fig. 5. — Frequency distribution of height of plant in brachytic X Boone, second 



generation. 



of the F t . With a sharp segregation into normal and brachytic 

 plants and a failure to increase the variability of height in the segre- 

 gated brachytic plants, the procedure to be followed in securing the 

 desired combination of brachytic stature with high jdeld becomes 

 greatly simplified and 



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eventual success be- 

 comes more certain. 

 It is necessary only 

 to back cross the best 

 yielding of the segre- 

 gated brachytic plants 

 upon the high-yield- 

 ing commercial varie- 

 ties and repeat the 

 procedure until the 

 desired combination is 

 obtained. 



While the mean 

 length of ear of the 

 brachytic segregates 

 in the second genera- 

 tion of the brachytic- 

 Boone hybrids is lit- 

 tle, if any, greater 

 than that of the 14 

 brachytic progenies, 

 several plants were 

 obtained which greatly exceeded in length of ear the directly de- 

 scended brachytic plants (Pis. XI and XII). The frequency dis- 

 tributions for ear length are shown in figure 6. 



The normal plants of the second generation exceed the brachytic 

 plants not only in stature but also in the length of the longest leaf, 



o 10 20 so 40 so eo ro cm 



Fig. 6. — Frequency distribution for total length of ears on 

 Boone, brachytic, Boone X brachytic F ls and the normal 

 and brachytic plants segregated in the brachytic X 

 Boone F 2 . 



