Phenological Differences Contributing to Yield in 300 Winter Wheat Lines Grown Under Water Stressed and Non-stressed Conditions

Three hundred cultivars and advanced lines belonging to the Triticeae Coordinated Agricultural Project (TCAP) Hard Winter Wheat Association Mapping Panel (HWWAMP) were grown under water stressed and non-stressed treatments in Greeley, CO, USA during the 2011-2012 field season. Water was managed using drip irrigation. The water stressed and non-stressed treatments received a total of 181 and 417 mm water between January 1 and physiological maturity, respectively. This contributed to a mean yield reduction of 48.4% in the stressed treatment.

HWWAMP entries were contributed by breeding programs throughout the Great Plains region. There were profound phenological differences within and between treatments, attributed both to diversity within the panel and magnitude and timing of water stress. Average booting, heading, anthesis, and physiological maturity dates were 3-8 days earlier under water stress. Developmental variability of all entries spanned a minimum of 12 days for anthesis and maturity dates in the stressed treatment, to 22 days among heading dates in the non-stressed treatment. Within treatments the middle 50% of plots ranged 3-7 days for each developmental stage. 

Temporal variation between treatments and irrigation scheduling contributed to unequal amounts and proportions of water available at different developmental stages between treatments. Both treatments received similar proportions of water between anthesis and maturity. The water stressed treatment received a greater proportion of water during booting, and lower proportions during heading and anthesis, compared with the non-stressed treatment. Phenotypic and genetic correlations among key physiological and yield-related traits will be presented and discussed.