quinby: mutations in sorghums 197 



produce adapted chinch bug-resistant varieties was carried on at 

 Lawton, Oklahoma. This breeding work, and studies of resistance 

 that went on at the same time, gave some information on the inher- 

 itance of resistance. Snelling, et al. (34) reported on work at Man- 

 hattan, Kansas, and Lawton, Oklahoma. Resistance was found to 

 be dominant and transgressive segregation for resistance indicated 

 that more than one gene was involved. Chinch bug resistance was 

 not put on a definite basis by this work, but there was ample evi- 

 dence of its inheritance. Varieties of sorghum have been classified 

 for susceptibility to damage from chinch bugs by a number of 

 workers in several states and this information has been summarized 

 in a book by Painter (24). Dahms (6), working in Oklahoma, found 

 that resistant varieties showed the greatest tolerance to a uniform 

 infestation of chinch bugs, that the insects preferred susceptible 

 varieties as hosts, that female chinch bugs lived longer on suscep- 

 tible varieties than on resistant ones, that more eggs were laid on 

 susceptible varieties, and that nymphs developed faster on suscep- 

 tible varieties. This work is significant and shows that there is in 

 plants actual resistance to insects produced by influencing the 

 biology of the insect. 



Male-sterile Genes 



Hybrid vigor was known to exist in sorghum long before the 

 difficulties inherent in producing crossed seed in a species with per- 

 fect flowers were overcome. The story of the advent of sorghum 

 hybrids has been told at least twice (31, 30). Cytoplasmic male- 

 sterility was the final answer to the problem of hybrid seed produc- 

 tion, but several genetic male-steriles that were apparently mutations 

 were worked with before cytoplasmic male-sterility was discovered. 



Antherless was the first genetic male-sterile worked with and 

 was found in 1929 (15). Male-steriles 1 and 2 were found about 

 1935, one in India and the other in Texas. It was proposed by Ste- 

 phens (36) in 1937 and ms 2 might be used for the production of 

 hybrid sorghum seed. By 1946, work had progressed with ms 2 to 

 a point where it appeared that hybrid sorghum might be put into 

 production. However, a still better male-sterile had been found 

 and work with ms 2 was abandoned. 



In 1943, Glen H. Kuykendall found in the Day variety a male- 

 sterile that must have arisen as a mutation. This abnormality proved 



