Composition of Starch and Protein in the Endosperm of Newly Generated Double Recessive Waxy and Opaque 2 Maize (Zea mays L.) Genotypes

Waxy maize with its pure amylopectin starch is the staple food of many ethnic minorities in hilly regions of Southeast Asia (SEA). A combination of waxy and quality protein maize (QPM) traits would improve the quality of protein of waxy maize for human consumption. Double recessive waxy-QPM (wx-o2) genotypes had been generated from Southern Chinese material by haploid induction of crosses heterozygous for the two quality traits with an absolutely conserved waxy type and an improved amino acid profile. The vitreous kernel trait (due to the additional modifier genes present in QPM) was lost in the wx-o2 plant material; this may be due to the waxy mutation, this is anyhow desirable for acceptance as waxy maize is preferred due to its soft grains. The content of the quality limiting amino acid lysine was greatly increased in double recessive wx-o2 genotypes compared to standard waxy maize, but still with a high variation among genotypes for future improvement. Conclusively, it was indeed possible to combine two grain quality mutations successfully within one genotype and prototypes of double quality wx-o2 are available now to contribute to meet human requirements in essential amino acids and thus reduce malnutrition in various regions of Asia.