Artificial pre-harvest sprouting chamber with moderate humidity better simulates field sprouting for soft winter wheat

Authors: Penning, Bryan

Submitted to: Biotechniques
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/5/2025
Publication Date: 12/13/2025
Citation: Penning, B. 2025. Artificial pre-harvest sprouting chamber with moderate humidity better simulates field sprouting for soft winter wheat. Biotechniques. 77(11–12):367–375. https://doi.org/10.1080/07366205.2025.2601538.
DOI: https://doi.org/10.1080/07366205.2025.2601538

Interpretive Summary: Pre-harvest sprouting, germination of the seed on the wheat spike, reduces grain quality, prices paid to US farmers by up to 30%, and yield by 50%. Natural sprouting does not occur every year in the field so an artificial inducement method is needed. Artificial methods to cause and measure pre-harvest sprouting under controlled conditions have been developed. However, they may not emulate naturally occurring pre-harvest sprouting in the field that occurs under lower relative humidity and less rainwater than artificial methods. This report describes construction of a chamber and development of a procedure to induce pre-harvest sprouting in a greenhouse better mimicking natural conditions. Artificial pre-harvest sprouting measures in ten varieties were strongly correlated with naturally occurring and overhead irrigation induced pre-harvest sprouting measured over three years. Some closely related varieties had large sprouting differences previously observed in natural rain events. Future study of pre-harvest sprouting in these varieties will likely uncover additional genes for pre-harvest sprouting resistance that can be used by wheat breeders to reduce pre-harvest sprouting in newly developed wheat lines benefiting US farmers. The developed chamber and procedure can be used in other crops such as rice, barley, rye, and sorghum.

Technical Abstract: Pre-harvest sprouting, germination of the seed on the spike, causes reduced grain quality and marketability in US wheat. Methods devised to induce and study pre-harvest sprouting vary significantly from one another in procedure, induction time, and/or measurement, and often fail to accurately reflect natural sprouting, which varies over years and locations. An artificial sprouting chamber and protocol with a shorter exposure time and relative humidity more relevant to field conditions was significantly correlated (P<0.01) with natural pre-harvest sprouting over three years for ten wheat varieties measured by alpha amylase activity. The alpha amylase activities of ten wheat varieties tested under the developed artificial sprouting chamber and protocol were significantly correlated (P=0.001) with those subjected to overhead irrigated field sprouting tests over three years. Four pairs of the ten varieties were genetically related but showed significantly different sprouting and alpha amylase activity. These varietal pairs may prove useful in studying the genetics of pre-harvest sprouting. While the study was performed in wheat, other susceptible crops such as rice, barley, rye, and sorghum could be tested using this method.