Breeding of Quality Protein Maize to Be Adaptable in Korea.

Demand for maize grain in Republic of Korea is about 9 million tons annually, which is used mainly for human consumption and livestock feed. Normal maize (Zea mays  L.) protein has been known as nutritionally poor due to deficiency in two essential amino acids (lysine and tryptophan). The use of quality protein maize (QPM) is one of the alternatives for a more efficient pig and poultry industry. Eighty-six lines of BC₃F₁ population were analyzed with opaque2 gene specific SSR marker for selecting heterozygote and sixty BC₁F₂ lines for selecting recessive homozygote. The normal inbred lines (KS5 and KS135) targeted for conversion to QPM are parental lines of high yielding single cross hybrid maize, Jangdaok, in Korea. In this study, we used inbred lines, CML178, CML182 and CML193 as QPM donor. QPM inbred lines were obtained from CIMMYT, Mexico. Amino acid contents were measured by an amino acid auto analyzer. The amount of each amino acid present in the samples was calculated with reference to the standard amino acid. QPM lines used for crosses were BC₃F₆. We selected eight QPM hybrids having high lysine content among experimented 54 hybrids. The average lysine content of non-QPM hybrids was 2.8 g/100g protein, but ranges of lysine contents of QPM hybrids were 4.1~4.9 g/100g protein. The average lysine content of QPM hybrids was 61% higher than that of non-QPM hybrids. These results indicated that selected QPM hybrids having high lysine content will help to improve quality of maize.