Evaluating Hard Red and White Spring Wheat Genotypes for Tolerance to Pre-Harvest Sprouting.

When physiologically mature kernels are exposed to high humidity or rain before harvest, the kernels can germinate in the spike.  This is known as pre-harvest sprouting (PHS) and has detrimental effects on bread making quality. The relationship between kernel color and PHS susceptibility is well known, and due to an emphasis on whole-grain products, the domestic and international milling and baking industries are soliciting the production of hard white wheat.  In the present work, we evaluated 24 genotypes, 12 hard red and 12 white, primarily adapted to the Northern Plains.  The traits evaluated were kernel color, alpha amylase activity, and each genotype was submitted to controlled PHS conditions and evaluated.  The 24 genotypes were grown in replicated trials at three locations over three years. Data analysis over the three years showed that the red kernels genotypes exhibited a higher tolerance to PHS than white genotypes, and a lower kernel colorimeter value as expected.  However, not all the white genotypes were equally susceptible to PHS, suggesting that not all seed dormancy is controlled by, or linked to, the kernel color genes.  Additionally, morphological aspects may play an important role in seed dormancy, or susceptibility to PHS.  The absence or presence of awns accompanied by how the genotype’s glumes encompass the seed as it matures may also affect PHS.