This investigation was carried out to study~ the
inheri tance of total protein content and amino acid lysine
in the three crosses (NM 5612 x NM 5272), (NM 5612 x G.
15) and (NM 5272 x G. 15) of grain sorghum. Potence ratio
exhibi ted over-dominance to the lower protein in the two
crosses (NM 5612 x NM 5272) and (NM 5272 x G. ·15) and to
the higher lysine in the later cross. Partial dominance
was observed to the higher protein in the cross (NM 5612
x G. 15) and to the higher lysine content in the cross
(NM 5612 x G. 15). Mid parents heterosis for protein content
in the cross (NM 5612 x G. 15) exhibited insignificant
positive value. Meanwhile mid and better parents heterosis
showed highly significant negative values in the other
two crosses. Lysine content showed heterosis with highly
significant positive values in the cross (NM 5272 x G.
15) and negative value in the two other crosses. Broad
sense heritability for protein ranged from 34% to 98%,
while for lysine was less than 40% in all crosses studied.
Number of genes for protein content ranged ~rom one to
three pairs, while for lysine was one pair, iH ':h dominance
gene effect for both characters. Correlation studies
indicate that lysine content is not at all correlated with
protein content, which means that both characters are
genetically conditioned by different genes.