26 BULLETIN 925, IT. S. DEPARTMENT OF AGRICULTURE. 



zagging of the rachis and subsequent twisting of the saddlebacks, 

 as suggested by Collins (2). 



The occurrence of ears at the base of the tassel and their restriction 

 to brachytic plants suggests a relationship between these plants 

 and the tassel-ear variation (6). Although the resemblance is not 

 marked, the variation is in much the same direction, and seems to 

 emphasize the association of brachysm with the development of pis- 

 tillate flowers. Economically the combination of brachytic with 

 Hopi has been a complete failure, and demonstrates the impractica- 

 bility of predicting the value of a hybrid from the characteristics of 

 the parents. 



CONCLUSIONS. 



Heritable variations occur frequently in maize. Few of these vari- 

 ations are of economic value and most of them are undesirable. One 

 of the most frequent variations is a marked reduction in stature. A 

 reduction in stature which affects only the length of the internodes 

 while the other organs remain unaltered in size or number is known 

 as brachysm. Such variations have appeared not only in maize but 

 also in cotton, beans, peas, squashes, oats, wheat, and tomatoes, where 

 some of them have been utilized by breeders to establish " bush " 

 strains. 



While brachytic maize plants are not of value directly for " bush " 

 qualities, the reduction in stature produces a plant which seems ad- 

 mirably adapted to dry-land and irrigation culture. 



The shortening of the internodes places more nodes in contact with 

 the ground and thereby increases the number of primary roots. 

 The plants in consequence of the short stature and highly developed 

 root system are exceptionally sturdy, while the leaves are brought 

 close together, thus effecting a partial shade. 



The yield of the brachytic variation as compared with the varieties 

 of the corn belt is low, but the reduced stature, sturdy erectness, and 

 increased root development offer advantages for extreme conditions 

 which may outweigh consideration of yield. Hybrids have been 

 made with high-yielding strains in an effort to improve the yield of 

 the brachytic plants, and a successful combination seems assured. 

 Brachytic stature apparently reappears uncontaminated in the perju- 

 gate generations of hybrids with varieties of normal stature. This 

 fact makes it possible to obtain rapidly the desired combination of 

 yield and stature by repeatedly " back crossing " the high-yielding 

 brachytic plants on high-yielding normal plants. 



Only two teratological forms have appeared in the hybrids be- 

 tween brachytic and normal plants. One of these variations has not 

 been observed previously, while the other is relatively common in 

 many nonbrachytic strains. 



