Pre-Harvest Sprouting (PHS) is a major threat to Michigan soft white wheat, and recent epidemics were experienced in 2008 and 2009. Alpha-amylase is an important component of PHS and the falling number (FN) test is used by industry to identify sprouted wheat that is unacceptable for various food products. The objectives of this study were to evaluate wheat cultivars adapted to Michigan for the activity of α-amylase and FN values around physiological maturity (PM) in natural conditions and multiple artificial PHS induction treatments. Twenty-four soft winter wheat genotypes with varying levels of susceptibility to PHS were planted in α-lattice designs in two locations in three years. Spikes were collected three days before PM, at PM, and three days post PM. Treated samples were freeze-dried, processed and evaluated for α-amylase activity and FN values. Genetic differences existed for both responses at all maturity categories in the absence of PHS induction. A clear trend was observed in the reduction of α-amylase and the increase in FN during the maturation in non-PHS conditions. For the study of PHS induction methods, genetic differences among 24 cultivars existed for both responses at PM in all misting treatments. After-ripening period had a significant effect on breaking dormancy for some lines, and an effective protocol for PHS screening at MSU was identified. `Jupiter', `Lowell' and `Caledonia' were highly susceptible, while `MSU E5024' and AgriPro `W1062' were two white wheat cultivars that showed consistent tolerance to PHS in this study.
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