|SANAD, MARWA - Washington State University|
|GILL, KULVINDER - Washington State University|
Submitted to: Botanical Studies
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/21/2016
Publication Date: 11/3/2016
Citation: Sanad, M., Garland Campbell, K.A., Gill, K. 2016. Developmental program impacts phenological plasticity of spring wheat under drought. Botanical Studies. 57:35. doi: 10.1186/s40529-016-0149-3.
Interpretive Summary: Our goal was to identify the growth stage of wheat that maintained the best ability to survive and regrow when exposed to drought. We assayed wheat in the greenhouse and imposed drought at tillering, booting, flowering and anthesis stages. The tillering stage was the most able to adapt to the drought conditions. Plants seems to be able to acclimate to drought because those exposed to a longer period of water restriction exhibited less grain loss than those exposed to shorter periods. Periodic stress was more severe than constant stress. These results will provide useful information for those who are designing drought resistance experiments on wheat in controlled environments.
Technical Abstract: Although phenological plasticity plays an essential role in breeding stress-tolerant spring wheat, the impact of development on the phenological plasticity remains poorly understood. Here we examine the effect of drought stress applied at tillering, booting, flowering, and anthesis on the morphological and physiological parameters of wheat (Triticum aestivum L.)including leaf rolling, wilting, yellowing and drying; Photosystem II fluorescence (PSII); plant height; yield; seed germination rate and seedling growth. Plants were exposed to the drought stress for 7, 14, 21-days or periodically during the growth season under the greenhouse conditions. Results demonstrate the tillering stage to be the least sensitive to drought, whilst booting and anthesis stages are the most sensitive. Therefore, tolerance traits could be overlooked if the stress is applied during either booting or anthesis stages. Generally, the dwarf and semi-dwarf spring wheat varieties appeared to be less susceptible to drought than tall varieties, while the tall varieties seemed to be more adaptive to limited water availability. Moreover, the tillering stage exhibited greater plasticity to the prolonged drought. We found that periodic stress had more pronounced inhibition of yield than the continuous stress. In particular, the 21-day stress resulted in less yield loss than discontinuous 7 and 14-day periods. Our study shows the importance of the phenological plasticity in designing screens for drought tolerance in spring wheat and proposes tillering as the most informative stage for capturing genotypes with tolerance to drought and desiccation.