Test Weight Stability and the IMPACT of GRAIN Characteristics on Test Weight in Spring Wheat.

Test weight (TW) is a major trait that drives wheat (Triticum aestivum L.) market grades and grain prices. The importance of TW lies in its positive association with flour yield and overall end-use quality. As a measure of weight-per-volume, TW is expected to be impacted by attributes such as; grain length (GL), grain width (GW), size, shape, single grain density (SGD), thousand-grain-weight (TGW) and packing efficiency (PE). The study’s objectives were to; (i) determine the grain characteristics that impact TW, (ii) determine the test weight stability across environments. Cultivars analyzed were from statewide crop performance trials (CPT) and were grown in 10 environments across South Dakota in 2011 and 2012. Single grain density (SGD) had the highest positive impact on TW. However, the impact of SGD was higher for winter wheat than for spring wheat. GW had the second highest impact on TW. High genotype x environment interaction component of SGD and PE may prevent breeders from using either trait to indirectly select for high TW.