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PAUL C. MANGELSDORF 



tends to maintain the maize-teosinte loci in a perpetual state of heterozy- 

 gosity. It already has been shown that homozygous teosinte genes in the 

 maize complex are decidedly deleterious. Therefore, if the teosinte genes are 



^*"«*W*^iW- 



D 



Fig. 11.7 — When the inbred 4R-3(^) iscrossed with Florida teosinte (C), thcFi hybrid ears 

 (B) are maize-like in having four-ranked ears, some double spikelets, and partially naked 

 seeds. When a teosinte-modified strain of 4R-3 (D) is crossed with Florida teosinte (F), 

 the Fi hybrid (E) is much more teosinte-like. The spikes are two-ranked, single, and the 

 seeds are completely enclosed. The teosinte derivative obviously carries "concealed" genes 



for these teosinte characteristics. 



to survive their deleterious effects, they must be modified through selection 

 or the genes must be maintained in a more or less heterozygous state. It may 

 be assumed that the latter mechanism would operate only if heterozygosity 

 for a group of maize-teosinte genes confers a distinct selective advantage 

 making the heterozygous combination superior, not only to the homozygous 

 teosinte genes (as it obviously is) but also to the corresponding homozygous 

 maize genes. 



