Creation and evaluation for corn germplasm of double recessive sweet-waxy genotype

Objective  To create double recessive sweet-waxy corn inbred lines, identify the effects of double recessive sweet-waxy genes on quality traits, and provide a reference and basis for sweet-waxy corn breeding.

Method  The double recessive sweet-waxy corn materials with wxwxsh₂sh₂ genotype were screened by molecular marker that linked with waxy corn recessive gene wx in F₂ populations obtained from one elite sweet corn line (M01) and three waxy corn lines (L33, L35 and L38). Then these materials were self-pollinated continuously, and 11 pure double recessive sweet-waxy corn inbred lines with wxwxsh₂sh₂ genotype were obtained in F₄ populations. Their soluble sugar content, total starch content and pericarp thickness were measured and compared with the corresponding sweet corn parent and waxy corn parent.

Result  The primer phi061, which was tightly linked to wx gene, amplified clear and codominant bands between sweet corn parent and waxy corn parent and was selected as the foreground selection marker of waxy gene. The average content of soluble sugar was 12.27% for double recessive sweet-waxy corn inbred lines, which was 2.55% higher than that sweet corn parent and far higher than that waxy corn parent. The average total starch content was 19.73%, which was 3.77% lower than that sweet corn parent, and far lower than that waxy corn parent. The pericarp thicknesses of crown and abgerminal regions of double recessive maize lines were in the interval of their corresponding parents.

Conclusion  It is a feasible way to create rapidly the double recessive sweet-waxy corn lines by molecular marker assisted selection. Their average content of soluble sugar is higher than that of sweet corn parent, the average content of starch is lower than that of sweet parent, and the average pericarp thickness is between their parents.