Quality and Biological Value of Grain Sorghum

Sceds from over 9,000 lines in the world sorghum [Sorghinn bicolor (L.) Moeochj collection were classified for endosperm phenotype to identify floury endospermO lines and evaluate each for potential increases in lysine concentration. Sixty-two floury endosperin lines were selected and analyzed for protein and lysine composition. Two floury lines of Ethiopian origin, IS 11167 and IS 11758, were exceptionally high in lysine at relatively high levels of protein. The average whole grain lysine concentration of high lysine lines IS 11167 and IS 11758 was 3.34 and 3.13 (g/100g protein) at 15.7 and 17.2% protein, respectively. Both lines were also high in pertcet oil. Carbohydrate analyses of whole grain samples of the two high Jysine lines were similar to that of normal sorghum grain ex. cept for a twofold increase in sucrose concentration. The high lysine gene altered the amino acid pattern in hi hl hl endospern tissue relative to normal crdo. spertn checks. The major changes were increased iysine, arginine, aspartic acid, glycine, and triptophan concertrations and decreased amoumnts of gltamic acid, proline, alanine, and leucine in tite hlhil I endospereu Inheritance studies suggest that the increased lysine concentration of each iiue is controlled by a single recessive gene, although it i: not known whether the genes from both lines are allelic. Tle high lysine gene(s) prescit iii IS 11167 and IS 11758 from Ethiopia is (are) herein designated as Id. The endospern of kernels 1.,mozygous for the /i gene is partially dented. The biological value of lite high lysihe lines much was higher than that of average sorghuni lines. It, a 28-day isonitrogenous feeding experiment the weight gain of weaniling rats was three tites higher on an IS 11758 ra­ thlt atd twice as high on an IS 11167 ration as weight gains on rations prepared fronm normal sorghtuin I;,es. When fed rations without ansy dilution except tie asual 2% vitaumin and 41!, mitineral supphlemtation, rats gained 94 g on high lysine sorghlmun (IS 11758) and 28.5 g on our turretol best nutritional quality sorghtin line (IS 2319), versus 91.5 g iOnopaltue.2 torn (Zr' rmys L.) atd 30.2 g on normal corn in a 28-day feeding trial. Feed efficiency ratios for this trial were 3.0 for higl, 7,sine sorghum, 6.8 for IS 2319, 3.4 for opaque-2 corn, and 7.4 for ntrinal corn. Additional inadex nords: Protein quality, Carbohydrate, PER, FER, Biological value, Cereal quality, Grain com­