Research establishing optimal sowing dates and irrigation can help to alleviate the adverse effects of drought on safflower (Carthamus tinctorius L.). The main objective of this study was to assess the effects of sowing date and irrigation quantity on safflower traits. Irrigation treatments were applied based on crop evapotranspiration (ET_c) at the vegetative, flowering, and capitulum development stages. Evapotranspiration increased as the number of irrigations increased. Morphological, yield and oil traits, and water use efficiency (WUE) were significantly higher in the early than in late sowing. Grain yield varied from 440 to 1,460 kg ha⁻¹ in early and from 340 to 1,240 kg ha⁻¹ in late sowing dates. Oil yield of early sown safflower varied between 188.56 and 338.84 kg ha⁻¹ and between 24.4 and 308.82 kg ha⁻¹ in late sowing. The oil yield of one supplemental irrigation in the vegetative stage (I1V treatment) was significantly lower than in treatments with two (I2VF, vegetative and flowering stages) and three supplemental irrigations (I3VFG, vegetative, flowering, and capitulum development stages) in early sowing. In late sowing, the oil yield of I2VF was higher than other irrigation treatments. The range of saving irrigation water in I1 treatments was from 57.0 to 83.0% in early sowing but with a corresponding 30.0 to 66.0% reduction in grain yield compared with full irrigation treatment. For most of the tested traits, irrigation in the vegetative and especially flowering stages improved safflower yield and WUE, and thus can be an alternative irrigation strategy for water conservation in dry regions.

中文翻译：

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红花生长物候阶段播种日期和灌溉制度对油料和种子产量的影响

研究确定最佳播种日期和灌溉有助于减轻干旱对红花（Carthamus tinctorius L.）的不利影响。本研究的主要目的是评估播种日期和灌溉量对红花性状的影响。在营养、开花和头状花序发育阶段，根据作物蒸散量（ET _{c ）进行灌溉处理。}蒸发量随着灌溉次数的增加而增加。早播的形态、产量和油性状以及水分利用效率（WUE）显着高于晚播。粮食产量在早期从 440 到 1,460 kg ha ^-1不等，从 340 到 1,240 kg ha ^-1在晚播日期。早播红花的产油量在 188.56 至 338.84 kg ha ^-1和 24.4 至 308.82 kg ha ^{-1之间变化}在晚播。营养期1次补灌（I1V处理）的出油量显着低于早播2次（I2VF、营养期和开花期）和3次补水（I3VFG、营养期、开花期和头状花序发育阶段）的处理. 在播种后期，I2VF的出油率高于其他灌溉处理。I1处理节灌节水幅度为早播期57.0%～83.0%，但与全灌处理相比，相应减产30.0%～66.0%。对于大多数测试的性状，在营养期特别是开花期灌溉提高了红花产量和 WUE，因此可以作为干旱地区节水的替代灌溉策略。