Dryland Wheat Domestication Changed the Development of Aboveground Architecture for a More Well-Structure Canopy

摘要

Domestication affects plant morphology and architecture.The domesticated mechanisms of different ploidy wheats remain unclear.We examined three different-ploidy wheat species to elucidate the development of aboveground architecture and its domesticated mechanism under environmentally-controlled field conditions.Architecture parameters including leaf, stem, spike and canopy morphology were measured together with biomass allocation, leaf net photosynthetic rate and instantaneous water use efficiency (WUEi).Canopy biomass density decreased from diploid to tetraploid wheat, but increased to maximum in hexaploid wheat.Population yield in hexaploid wheat was higher than in diploid wheat, but the population fitness and individual competition ability was higher in diploid wheats.Plant architecture was modified from a compact type in diploid wheats to a incompact type in tetraploid wheats, and further to more compact type of hexaploid wheats.Biomass accumulation, population yield, harvest index and the seed to leaf ratio increased from diploid to tetraploid and hexaploid due to an increase in specific internode weight and greater upward canopy density in hexaploid and tetraploid than that of diploid wheat.Leaf photosynthetic rate and WUEi decreased from diploid to tetraploid and increased from tetraploid to hexaploid due to more compact leaf type in hexaploid and diploid than in tetraploid.Grain yield formation and WUEi were associated with spatial stance of leaf and biomass shift resulting from long-term domestication and breeding practice of dryland wheat.We conclude that the ideotype of dryland wheats could be based on spatial reconstruction of leaf type and further exertion of leaf photosynthetic rate.