Effect of Varietal Difference in Root System on Hydraulic Conductance in Potatoes Under Different Soil Water Conditions and Planting Dates
2015
Deguchi, Tetsuhisa | Iwama, Kazuto | Matsumoto, Manabu | Tanigawa, Jyun
To improve drought resistance of potato (Solanum tuberosum L.), we bred four varieties with large root mass and registered them as Konyu-1 to Konyu-4 in 2007. In the present study, two experiments were conducted to clarify the effect of improved root system on plant hydraulic conductance (Kₚₗₐₙₜ) and drought resistance under field conditions. In the first experiment, Kₚₗₐₙₜ and total root length (TRL) were compared for three Konyu varieties (Konyu-1, Konyu-2, Konyu-4) and Konafubuki (check variety with small root mass) cultivated under irrigated and droughted conditions. In the second experiment, the effect of three different planting dates on Kₚₗₐₙₜ and TRL was compared for Konyu-4 and Konafubuki. Regardless of soil water conditions and planting dates, Konyu varieties showed higher Kₚₗₐₙₜ compared with Konafubuki. In addition, a close positive relationship between TRL and Kₚₗₐₙₜ was observed in both experiments. Konyu varieties also showed higher leaf water potential (ψₗₑₐf) regardless of soil water conditions and planting dates, resulting in a smaller reduction in transpiration rate per leaf area (T) under droughted condition. Present results indicated the contribution of root system improvement in potato crop to drought resistance on the basis of plant hydraulics. Improved TRL of Konyu varieties contributed to enhance Kₚₗₐₙₜ and to maintain higher ψₗₑₐf and T under droughted condition.
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