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 (AMY1). 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 alpha 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. HFN of the 123 lines showed a normal distribution, ranging from 97 to 509 s. The HFN of four accessions were less than 200 s, 25 were between 200 and 300 s, 68 were between 300 and 400 s, and 25 were above 400 s. HFN and AMY1 values 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. Correlations between HFN with heading date, plant height, and grain yield were all non-significant. A total of 4466 SNP markers were used in association mapping and 14 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.