quinby: mutations in sorghums 201 



A yellow endosperm character was introduced into the United 

 States from Nigeria by O. J. Webster in 1951. The yellow color is 

 caused by carotene and xanthophyll. The yellow endosperm character 

 is being bred into adapted varieties. The amounts of carotene and 

 xanthophyll in the yellowest sorghum varieties obtained thus far 

 are one-quarter to one-half those contained in yellow corn. 



Sorghum stalks are pithy or juicy and sweet or nonsweet. 

 According to Hilson (9), pithy is a simple dominant to juicy. Accord- 

 ing to Ayyangar, et al. (2), 17 to 20 per cent of juice can be extracted 

 from pithy-stalked varieties and 33 to 48 per cent from juicy vari- 

 eties. Pithy-stalked plants have white leaf midribs and juicy-stalked 

 plants opaque midrids. Sorgos are quite juicy and grain sorghums less 

 juicy or quite dry. Kafirs have juicy stems and feteritas and broomcorn 

 dry stems. 



The inheritance of sweet and nonsweet stalks was studied by 

 Ayyangar, et al. (2) and they found nonsweet to be a simple dom- 

 inant to sweet. These authors also reported genes for sweetness 

 and juiciness to be independent in inheritance. Sorgos have sweet 

 stems, but most grain sorghums have little sweetness. However, 

 feterita, which has dry stems, tastes sweet if the dry pith is chewed. 

 Sweet sudangrass is both juicy and sweet, whereas the introduced 

 variety is pithy and nonsweet. 



Summary 



Sorghum is an introduced species in the United States and is 

 grown on about 20 million acres. The mechanization of agricul- 

 ture and changes in sorghum that began about 30 years ago have 

 changed sorghum from a feed crop for use on the farm into a cash 

 grain crop. 



The species has been transformed by producing early matur- 

 ing; and shorter statured varieties. Alleles for resistance to several 

 plant diseases and to one insect have been found. Cytoplasmic 

 male-sterility has been found and methods of hybrid sorghum seed 

 production devised. Several other desirable characters have been 

 bred into improved varieties, including improved seed and glume 

 colors, waxy endosperm, yellow endosperm, and either pithy or juicy 

 stems. 



