Some genetic and biochemical characteristics of a new source of maize opaque-2 mutant

The opaque kernels separated from the F1 of crosses of our opaque-2 strains with normal inbred lines contained 45, 50 and 74 percent more lysine in the whole kernel than the translucent kernels from the same ear. The opaque kernels from these crosses contained almost the same level of lysine as the parental opaque-2 strains.Some of our opaque-2 strains contain 63 to 122 percent more lysine than the tested dent or flint normal inbred lines. In comparison with opaque-2 Purdue, four opaque-2 strains had almost the same lysine content and a strain labelled as SP-1 No. 15 contained 25 percent more lysine and 73 percent more tryptophan. Some of our opaque-2 strains contained 55 to 100 percent more tryptophan in the whole kernel than opaque-2 Purdue.In contrast to lysine content, the transmission of the tryptophan content from opaque-2 strains to opaque kernels from their crosses shows variability.We found weak positive correlation (r = +0,3057) between lysine and tryptophan content in opaque-2 kernels.Our opaque-2 strains had a higher lysine content in the endosperm than did opaque-2 Purdue 22.1 - 36.6% more, and compared with normal lines they had 109.5 - 142.6% more.It is apparent that a new source of opaque-2 mutant gene, which has the same genetic and biochemical characteristics as the opaque-2 mutant discovered by Mertz, Bates and Nelson (1964), has been found in a completely new, genetically divergent, strain derived from a large number of populations.