A BRACHYTIC VARIATION IN MAIZE. 



A brachytic plant appeared also in a progeny of the Esperanza 

 variety of Zea hirta (PI. VI). This plant was not self-pollinated, 

 but was crossed with a normal plant of the Chinese waxy variety. 



HWHS/9S 0£UT ?LVO/?Af#J. 



CHI NESE mxr£ NORMAL 



OH1 &LL NOfffrf/fL 



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Fig. 1.- — Pedigree chart of a brachytic strain which does not breed true. None of the 

 progenies shown in this chart were the result of self-pollination except DhlL16, the 



progeny of a brachytic plant. 



The hybrid has been designated Mh 17 by Collins (1). The first- 

 generation plants were all much taller than either parent. Three 

 plants were hand-pollinated, but not selfed. The second-generation 

 progeny of these plants gave no evidence of brachysm, as is shown 

 by the frequency distribution for plant height (fig. 2). The modal 

 height of the second-generation plants was 190, which is the aver- 

 ^ age height of normal Es- 



peranza plants. The bra- 

 chytic Esperanza parent 

 of this hybrid was 105 

 cm., while the Chinese 

 parent was but 167 cm. 

 high. Succeeding gen- 

 erations have continued 

 normal in stature, al- 

 though progenies differ- 

 ing widely in height have 

 been isolated. It is hoped 

 that crosses between some of these progenies and true-breeding 

 brachytic strains will explain the complete disappearance of this 

 variation in the Mh 17 hybrid. 



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eo ao 200 20 4-0 so 

 //F/GHT /A/CS/VT/M/ETEfPS 



Fig. 2. — Frequency distributions of height of plant 

 of the first and second generation hybrid between 

 the brachytic Esperanza plant shown in Plate VI 

 and a Chinese waxy plant of normal stature. 



