Spring Safflower Physiology, Growth and Yield As Affected By Different Irrigation Management Practices in Semi-Arid Conditions.

Spring safflower physiology, growth and yield as affected by different irrigation management practices in semi-arid conditions

 

Safflower is a deep rooted, stress tolerant crop that originated in desert environment and could be well adapted to the semi-arid agriculture. A field experiment was conducted to assess drought physiology and yield formation of two diverse spring safflower genotypes with or without full profile moisture. Half of experimental blocks were pre-irrigated with 160 mm of water to fill the empty profile from previous crop of corn, while other half remained depleted. Irrigation levels I₁ (75 mm), I₂ (150 mm), I₃ (225 mm), I₄ (300 mm) and I₅ (375 mm) were given to both pre-irrigation and no pre-irrigation blocks. Pre-irrigation treatment increased seed and oil yield by 28% and 29% over no pre-irrigation, respectively. Highest seed and oil yield was observed under I₅ irrigation level which was not significantly different from I₄. Higher water extraction from soil profile and lower transpiration were observed in low water availabilities. Improved water availability through pre-irrigation and higher irrigation levels increased RWC, photosynthesis and WP. Plants that received pre-irrigation treatment had higher WUE than no pre-irrigation treatment. Safflower utilized water with same efficiency even under limited water availabilities and WUE did not differ among irrigation levels or between cultivars. Biomass partitioning increased with increase in irrigation water, up to a certain level. Among all irrigation levels, lowest biomass partitioning was noticed in I_5. Results indicate that the pre-irrigation is beneficial for safflower to improve its physiology, growth and productivity. Improved head number, seeds per head and photosynthesis increased seed yield in safflower with increasing water availabilities. In general, both the cultivars responded similarly to water stress treatments.