18th Congress of the European Society for Agronomy

Phase-specific genotype-by-light interactions determine kernel number and yield potential in wheat

Not scheduled

15m

Les Dortoirs (1st floor) (The Couvent des Jacobins)

Poster Synergies between short- and long-term goals Poster session #1

Speaker

Tsu-Wei Chen (Humboldt Universität zu Berlin)

Description

Wheat is grown in variable environments and the fluctuations during critical developmental phases may have significant effects on final grain yield, especially in the context of increasingly frequent climate extremes. Therefore, it is important to understand the impacts of short-term (days) natural fluctuations of environmental variables during specific physiological phases that correspond to the formation of yield components (spike number, SN; kernel number per spike, KpS; and thousand kernel weight, TKW) and may contribute to explaining the gap between potential and actual yields in wheat. Using a novel statistical approach, we first estimated the sensitivities of SN, KpS and TKW to variations in global radiation, temperature and precipitation across 81 time-windows ranging from double ridge to seed desiccation in 220 winter wheat cultivars. Most time and cultivar specific sensitivity responses occurred in time windows corresponding to the major physiological sub-phases during spike and kernel development. Interestingly, kernel number per spike was the most sensitive yield component affected by short-term fluctuations of light and temperature, especially during the sub-phase between yellow anther and tipping and at pre-grain filling. We further tested 16 wheat cultivars differing in their stage specific sensitivity of KpS to light intensity in growth chamber experiments. Our data confirmed the sub-phase specific effects of light on floret development and kernel abortion during the yellow anther and tipping phases, and the sensitivity differed by a factor of three between cultivars. Our results reconcile contradicting findings from previous studies, reveal previously undetected effects of environmental fluctuation and provide deep insight into cultivar specific three-way interactions between phenology, yield formation and environmental fluctuations. This information can be further used to optimize yield potential.