| Abstract: | The lysine and protein content of corn seed was determined for inbred lines and crosses among inbred lines, to gain a better understanding of the genetic variation of these characters. Lysine content was determined by an automatic amino acid analyzer. Protein content was estimated by means of a Coleman nitrogen analyze. Other methods of lysine determinations were investigated, but none proved satisfactory. The genetic variation among a group of 55 inbred lines was investigated. A 6x6 diallel cross experiment was conducted to study the nature of the genetic variation. Crosses of two different sources of opaque -2, o (line underneath) ₂, to four inbred lines were used to determine the effect of genetic background on the expression of the o (line underneath) ₂ gene in the one dose level. The o (line underneath) ₂ gene is known to have a major effect on lysine content in corn seed. Selfed progeny of homozygous o (line underneath) ₂ segregates obtained from crosses of 10 inbred lines to one source of o (line underneath) ₂ were used to detect differences in the genetic background of the inbred lines that affect the expression of the homozygous o (line underneath) ₂. The genetic variation among inbred lines was found to be highly significant for protein content and for lysine content expressed as a per cent of either protein or seed weight. A positive correlation of +0.46 was found for lysine, expressed as a per cent of seed, and per cent protein; whereas, a negative correlation of -0.44 was found for g. lys./100 g protein and per cent protein.... |
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