Association Mapping of Hagberg Falling Number in Hard White Spring Wheat Accessions.

Hagberg falling number (HFN) is a simple and rapid measurement for determining α-amylase activity (AA). It is used widely in grain classification, quality control, and marketing. Wheat grains with a low falling number can be the result of either pre-harvest sprouting (PHS) or late maturity α-amylase (LMA). Both PHS and LMA significantly reduce end-use quality of wheat. The objectives of the current study are to identify QTL and markers associated with HFN in 123 hard white spring wheat accessions from USDA-ARS National Small Grain Collection under three water/nitrogen treatments. HFN of the 123 lines showed normal distributions in all three treatments, ranging from 97 to 549 s. Eight accessions had HFN less than 300 s in all three treatments. HFN and AA values of treatment 1 were correlated (r = -0.83) in accessions with HFN values smaller than 300 s, but non-significant in accessions with HFN greater than 300 s. A total of 4454 SNP markers were used in association mapping and 8 SNP markers on four chromosome regions were significantly associated with HFN at α = 0.1 (Bonferroni correction). The SNP markers and high HFN lines identified in the current study can accelerate development of hard white wheat varieties resistant to PHS and LMA.