Responses of spring wheat exposed to pre-anthesis water stress.
Robertson M.J. | Giunta F.
Spring wheat cv. Yecora 70 was exposed to soil water deficits during 3 phases between emergence and anthesis: early (22 days after sowing to terminal spikelet), mid (terminal spikelet to anthesis) and late (early boot to anthesis). The extension rate of the lamina and pseudostem was reduced when more than 50 percent of the extractable soil water had been extracted from the root-zone, independent of the stage when stress was imposed. Stress treatments reduced spike biomass at anthesis to 58-94 percent of that in the well-watered control, but had little effect on the pattern of biomass partitioning to the spike and the proportion of anthesis biomass as spike. Stress after terminal spikelet reduced the ratio of kernel number to anthesis spike weight by 50 percent, suggesting that reduced kernel number under stress may not be solely due to a restricted assimilate supply. The constancy of the ratio of kernel number to anthesis spike weight was shown not to hold under water stress.Show more [+] Less [-]