Increasing kernel density for two inbred lines of maize

Improving grain quality of maize (Zea mays L.), including endosperm hardness and density, is often a breeding objective. Dense seed is preferred by dry millers and for alkaline processing, and can command a price premium at market. This study attempted to increase kernel density in a backcrossing program for two inbreds of maize using two selection techniques, specific gravity of kernels and the percentage of sinking kernels in a salt solution (or sinkers). Two inbreds, B73G and A632, were crossed with synthetics exhibiting apparent high kernel density, and several generations of backcrossing and self-pollination followed. Examples of mean comparisons of backcross-derived inbreds with the recurrent parents, B73G and A632 are as follows: B73G-Specific gravity, 1.251 and 1.206; Sinkers, 62.3 and 14.9%; and A632-Specific gravity, 1.266 and 1.250; Sinkers 45.4 and 29.1%. Both the specific gravity and sinkers techniques were successful for increasing kernel density during backcrossing.