High-speed NIR segregation of high- and low-protein single wheat seeds

Wheat breeders need a nondestructive method to rapidly sort high- or low-protein single kernels from samples for their breeding programs. For this reason, a commercial color sorter equipped with near-infrared filters was evaluated for its potential to sort high- and low-protein single wheat kernels. Hard red winter and hard white wheat cultivars with protein content >12.5% (classed as high-protein, 12% moisture basis) or < 11.5% (classed as low-protein) were blended in proportions of 50:50 and 95:5 (or 5:95) mass. These wheat blends were sorted using five passes that removed 10% of the mass for each pass. The bulk protein content of accepted kernels (accepts) and rejected kernels (rejects) were measured for each pass. For 50:50 blends, the protein in the first-pass rejects changed as much as 1%. For the accepts, each pass changed the protein content of accepts by approximately equal to 0.1%, depending on wheat blends. At most, two re-sorts of accepts would be required to move 95:5 blends in the direction of the dominant protein content. The 95:5 and 50:50 blends approximate the low- and high-protein mixture range of early generation wheat populations, and thus the sorter has potential to aid breeders in purifying samples for developing high- or low-protein wheat. Results indicate that sorting was partly driven by color and vitreousness differences between high- and low-protein fractions. Development of a new background specific for high- or low-protein and fabrication of better optical filters for protein might help improve the sorter performance.