Pre-harvest sprouting resistance of soft winter wheat varieties and associated grain characteristics

Authors: Ji, Taehyun; Penning, Bryan; Baik, Byung-Kee

Submitted to: Journal of Cereal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/2/2018
Publication Date: 8/6/2018
Publication URL: http://handle.nal.usda.gov/10113/6120047
Citation: Ji, T., Penning, B., Baik, B-K. 2018. Pre-harvest sprouting resistance of soft winter wheat varieties and associated grain characteristics. Journal of Cereal Science. 83:110-115.

Interpretive Summary: Sprouting of wheat grain before harvest, so called pre-harvest sprouting (PHS), and the resultant decrease in falling number (FN), measure of the degree of sprouting, is a wide spread concern in production of US wheat and adversely affects grain quality, marketability and price. Wheat grain of less than 300 FN is subjected to considerable price reduction and often rejected for food uses, resulting in reduced income for the growers and subsequent decrease in wheat acreage. Growing wheat varieties possessing the resistance would be the definitive option for ensuring the production of wheat grain free of PHS. Insufficient efforts for the identification of wheat varieties carrying PHS resistance and breeding those varieties have, however, existed, likely due to the challenges including the variation in climatic conditions over crop years and absence of effective and efficient methods for screening wheat varieties and breeding lines for PHS resistance. An attempt was made to identify wheat varieties exhibiting PHS resistance, and wheat and grain characteristics associated with PHS resistance. Five soft winter wheat varieties were identified to possess PHS resistance and exhibited much higher FN and lower '-amylase activity of grain than other varieties when subjected to sprouting climatic conditions. Soft winter wheat varieties with red seed coat color exhibited better sprouting resistance than those with white seed coat color. The implication of hair (awn) presence in the head (spike) to PHS resistance was less evident compared to that of seed color. The genetic potential of a wheat variety for test weight (bulk density) is identified as a possible predictor of PHS resistance as indicated by significant relationship between test weight of grain produced without being exposed to sprouting conditions and FN of grain exposed to sprouting conditions. The obtained information will be helpful for wheat growers in selecting wheat varieties for planting with less concern on PHS of grain, and for breeders in screening wheat breeding lines with PHS resistance potentials. Test weight of wheat grain, identified as a grain trait associated with PHS resistance, presents a direction for further investigation of biochemical mechanism involved in PHS resistance.

Technical Abstract: The varietal differences in pre-harvest sprouting (PHS) resistance and associated grain characteristics have yet to be understood. We tested the grains of 125-166 soft winter (SW) wheat varieties grown for three years for falling number (FN), a-amylase activity, and degree of sprouting (DS) under field sprouting (FS) and spike wetting conditions, and determined the characteristics of grain produced under non-FS conditions for two years.. Eleven to 31 varieties exhibited FNs higher than 200 under spike wetting conditions, and 16 to 99 varieties exhibited FNs above 300 under FS conditions. Red wheat varieties showed significantly (p<0.05) higher FNs than soft white wheat varieties for the grains produced under FS conditions in 2015 and 2017 and subjected to spike wetting in 2017. Awned varieties showed significantly (p<0.05) lower FNs and higher DS values than awnless varieties when subjected to spike wetting in 2016. Falling number, a-amylase activity, and DS of grain produced under FS in 2015, 2016 and 2017 exhibited significant correlations with test weight (TW) (p<0.01) of grain produced under non-FS conditions in 2016 and 2017. Five awnless red wheat varieties exhibited relatively high FNs, even under FS and spike wetting conditions.