In rainfed cropping systems, crops are typically subjected to terminal stresses, which diminish the assimilation process. Information regarding safflower (Carthamus tinctorius L.) dry matter dynamics during the seed-filling period and its association with yield-forming components is lacking. Field experiments over two years were conducted to assess the influence of nitrogen (N) fertilization levels (0, 100 and 200 kg ha⁻¹), sowing time (autumn vs. spring) and genotype (two hybrids and an open-pollinated variety) on growth, assimilate remobilization, achene- and oil yield of safflower, and to identify early crop attributes as predictors of yield. Greater than 100 kg N ha^-1 were required to optimize achene yield (> 4 Mg ha^-1). On average, N promoted early growth and increased capitula and achenes per unit area compared with the non-fertilized control. The higher the availability of assimilates at the source, the greater their remobilization to sink (r = 0.823, P < 0.01), which was in turn associated with achene yield (r = 0.53, P < 0.05), provided that a critical sink size (number of achenes) had been established during flowering. Dry matter remobilization efficiency ranged between 29.5 % and 39.1 %. Under favorable conditions, hybrids exhibited higher achene- and oil yield than the variety. Oil yield was almost entirely (98 %) determined by achene yield. Autumn sowing increased the average achene yield (28 %) and oil production (20 %) compared with spring sowing. Harvest index (HI) ranged from 0.17 to 0.35 and was associated with achene yield (r = 0.703, P < 0.01). Achene yield could be predicted by measurements of dry matter at anthesis, while the estimation of biomass from plant height measurements was not applicable in safflower. Findings highlight the value of properly designed cropping systems for safflower production based on environmental variables and crop management practices, which can support high yields and improve N management.

在雨养种植系统中，作物通常会受到终末压力，这会减少同化过程。缺乏关于种子灌浆期间红花 ( Carthamus tinctorius L.) 干物质动态及其与产量形成成分的关联的信息。进行了两年多的田间试验，以评估氮 (N) 施肥水平（0、100 和 200 kg ha ^-1）、播种时间（秋季与春季）和基因型（两个杂种和一个开放授粉品种）的影响对红花的生长、同化物再动员、瘦果和油产量的影响，并确定早期作物属性作为产量的预测因子。需要超过 100 kg N ha ^-1以优化瘦果产量（> 4 Mg ha ^-1）。平均而言，与未施肥的对照相比，N 促进了早期生长并增加了单位面积的头状体和瘦果。源头同化物的可用性越高，它们向汇的再动员越大（r = 0.823，P < 0.01），这反过来又与瘦果产量相关（r = 0.53，P < 0.05），前提是临界汇尺寸（瘦果数量）已在开花期间建立。干物质再动员效率介于 29.5 % 和 39.1 % 之间。在有利条件下，杂种表现出比品种更高的瘦果和油产量。油收率几乎完全（98%）由瘦果收率决定。与春播相比，秋播增加了平均瘦果产量 (28%) 和石油产量 (20%)。收获指数 (HI) 范围为 0.17 至 0.35，与瘦果产量相关（r = 0.703，P < 0.01）。瘦果产量可以通过花期干物质的测量来预测，而从植物高度测量中估算的生物量不适用于红花。研究结果强调了根据环境变量和作物管理实践为红花生产适当设计的种植系统的价值，这可以支持高产并改善氮管理。