quinby: mutations in sorghums 193 



Table 5. — Comparison of Plant Characters in Sooner Milo Genotypes that 

 Differ by One Height Allele in Populations Grown at Chillicothe, Texas, in 1947. 



ulation SA 1295 was 41 cm. The difference between 2-dwarf and 3- 

 dwarf plants in population SA 5535 was 47 cm. These differences were 

 highly significant. No significant differences occurred between the 

 height genotypes in number of leaves, days to bloom, width of leaf, 

 or number of stalks per plant. The 5-gram difference in weight of 

 heads in the height classes of 1 -dwarf and 2-dwarf plants in popu- 

 lation SA 1295 was not significant. However, the 37-gram differ- 

 ence in favor of the 2-dwarf over the 3-dwarf class of population 

 SA 5535 was significant statistically. Why the 3-dwarf plants in 

 population SA 5535 produced lighter heads than 2-dwarf plants 

 is not apparent. Perhaps the smaller head yield of the 3-dwarf class 

 could be due to shading from the taller 2-dwarf plants as the two 

 heights occurred at random in the rows. Regardless of this excep- 

 tion in head weight, the dwarfing genes in sorghum appear to be 

 truly brachytic. 



This brachysm, true to its definition, does not influence length 

 of the sheath of the upper leaf, peduncle length, or head length. 

 Fortunately, the length of the peduncle is not shortened, otherwise 

 the head of short plants would not emerge from the boot. Also, 

 if the rachis and seed branches of the head were shortened as much 

 as the internodes, short-statured sorghums would have heads as 

 compact as those of Pig-nosed durras. Data to show the lack of 



